Suntuf Installation Guide and Tips

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Suntuf Installation Guide and Tips

18th Jul 2016

Installation of Suntuf is easy when you plan the job right!

Just keep our top installation tips in mind before you start to install your new Suntuf product.

Fall, pitch or slope?

Firstly, fall.  A five degree fall is recommended as minimum for ensuring that it does not leak, remains clean and maintains structural integrity.

A good slope helps to move water off the roof.  Flat roofs are more prone to water pooling (in sever cases) and leaking when the water cannot be dispersed quick enough. Designing in a good fall is always important at the start of a project.

All polycarbonate sheets are transparent (you can see through them) or translucent (light comes through them but you can’t see through them clearly). This means that you will be able to see, to some degree, what is on top of them.  Leaves, dirt, dust, bird droppings, etc.  The better the fall on your roof the easier it will be for these things to fall off or wash off.

Most manufactures recommend a minimum of 5 degrees (or 8.8%) fall.  This means for every metre the sheet runs horizontally it should drop about 88 mm.

Spans – Where you will need your purlins

All profiled polycarbonate sheets require purlins or battens for fixing.  These structural lengths of timber or metal run perpendicular to the fall of the sheet – see the below image for a visual explanation.  Different profiles have different spanning capabilities.  The below spans are given for a standard N3 wind rating, if you are in a high wind area you may require additional fixings and structure – call us to discuss.

Corrugated 800 mm End Spans and  1000 mm Mid Spans

Greca 900 mm End Spans and 1200 mm  Mid Spans

Trimdek 900 mm End Spans and 1200 mm  Mid Spans


Suntuf polycarbonate sheets can be cold curved.  The shape of the sheet (the profile) will determine how tightly it can curve.  If you want to determine if a sheet can cold curve to to suit your structure you will need to know the following information:

The chord: the horizontal distance from one side of the roof to the other.

The height: the vertical distance from the imaginary horizontal chord line to the top of the apex.

See the below diagram.


We can cut sheets to length for you free of charge.  Otherwise, sheets can be cut using a fine tooth circular saw, a jigsaw, or even with a good pair of scissors.  When using power tools you will need to clamp the sheet as close to the end as possible to stop vibration. Remember to allow for some overhang to ensure that water from the sheet will fall into the gutter and not onto your structure.


All materials expand and contract when they heat up and cool down, and polycarbonates move more than most roofing materials. This means that it is important to allow the sheet room to move a little after it has been installed.  This is easily done by following a few rules.

Firstly, drill an over-sized hole in the sheet for the screw fixing. Both Clearfix and OneShot branded screws have cutters embedded on the screw to save you time in completing this step – they cut the hole when you put the screw in.

Secondly, by allowing a small gap between the ends of sheets and where they might come up against another object – like a wall fascia. This isn’t as important on the barge sides as the majority of the expansion will occur along the length of the sheet.


As a rule – they are not recommended.  Silicons can act as an adhesive which can stop the sheet from moving (see above).  Some silicons can also affect the chemicals in the sheet which protect it from UV radiation.  If you can’t avoid it use a neutral cure or non-acidic silicon sparingly.  Be sure not to put it along the length of the sheet where you will see the most expansions and contraction.


Purlin tape can be used to stop creaking of the sheet with expansion and contraction. As the name suggests it is applied to the purlin prior to installing the sheet, and acts as  buffer.  It is particularly useful with painted purlins, where in hot weather the paint can become tacky and cause the sheet to stick and make more noise as it expands and contracts.

Flashings are used to seal the edges of the sheet.. There are a few different types that are common. Ridge capping is used to flash a gable at the peak of the roof. Barge Flashing is used on the sides of the structure to cover the edges of the sheet and sometimes protect the timber structure underneath. And Apron Flashing is used to seal between a vertical wall or fascia and the roof itself.  You can get a number of these flashings in polycarbonate or have them manufactured in metal.


Infills can be used between the sheet and any flashings or structure for weatherproofing.  Infills are available in the standard roofing profiles: Corrugated, Greca or Trimdek (5-rib).  An infill may be used between the the sheet and the Apron flashing on the top edge of the roof, or between the purlin and the sheet at the gutter end of the sheet to weather seal.


Back channels are normally used when the top end of the sheet is being installed directly underneath a gutter.  A metal channel C- section is combined with foam to seal the end of the sheet in these circumstances.




We supply 2 brands of screws; Clearfix or Oneshot.

One Shot screws are available in either a timber T17 or a metal Tek.  When screwing into hardwood or larger gauge metals they are the screw of choice.  They come with a cutter to pre-cut a 10 mm expansion hole into the polycarbonate sheet, and a soft rubber washer to seal the large hole.

The Clearfix screw is a  dual purpose head – suitable for both timber and metal installations. They also come with a cutter and washer to suit polycarbonate.


Store Suntuf on a flat surface away from direct light and moisture.


Warm soapy water, with a soft sponge.  Be careful not to scratch the sheet. Rinse well.  Don’t use other chemicals.

Installing the Polycarbonate

The standard installation guide covers the actual fixing of the sheets well.  Make sure you read it.  Find it here… Suntuf Installation Guide.

Allow for the sheet to overhang the lower purlin by 50 mm.

Sheets will arrive with labels showing ‘This side up’ and it is very important to install the sheets in the correct orientation. A UV layer on the polycarbonate, protect the sheet from premature breakdown.  Put it up the wrong way and you will experience decreased life for your polycarbonate.

When screwing the sheets keep the screw straight to ensure weather seal of washer. Don’t over-tighten the screws.  If you’re not using the branded screw mentioned above, be sure to pre-drill a 10 mm holes in sheet.

Install the first sheet screwing along the ‘lower (gutter) purlin’ from the outside (Barge side) towards the middle of the structure. Screw every other corrugation along the bottom purlin.  Install the sheets without stress – that is; don’t pull, tension or twist the sheets.

Next move up to the next purlin screwing across the sheet in the same direction.  Place screws as per the below diagram and continue this for all the ‘internal purlins’ or ‘mid purlins’.

Finally, Screw along the top ‘upper purlin’ placing a screw every second corrugation.

Move along to the next sheet.  Use one corrugation side lap, ensuring the lap is against the primary direction of wind/rain.  Finish the job by installing any required flashings.  Don’t forget to remove any stickers or tapes from the sheet.

Thanks for looking at our Suntuf Installation Guide and happy installing!

289 thoughts on “Suntuf Installation Guide and Tips

    1. Hi Jesse

      Yes, valley fixing is one method… generally we would recommend crest as per a standard roof install! See my response to Roy for a full rundown.

      1. I’m installing clear polycarbonate suntuf roofing on my pergola. The first panel will start with the edge or higher side of the corrugated panel up. But when prefitting the panels across to see where it ends, the last panel will finish with the lower edge or lower corrugated part down because that’s how the plastic mounts had to line up across the pergola top. Is this a problem? If so how can I correct this? Thanks.

        1. Hi Jose

          Most importantly make sure you are installing the panels the correct way up… there is a stick (or inkjet writing ) on the sheet to help you orientate it.

          Usually the sides are covered with a barge flashing, this will cover a few corrugations on the top of the sheet and ‘keep them dry’. IF your not worried about water off the side then its fine to leave as is.

          Team PC

  1. I am building a steel work shop/ shed,6×5 metres. On the north facing gable end I am going to put a horizontal 6m sheet of diffused ice and on the south side a 6 m horizontal sheet of clear (to maximise light)
    With your years of experience , please let me know the best way to fix to the steel studs
    Novice shed clad der

    1. Hi Roy

      Thanks for the question.

      I assume that you will be running the ribs on the sheet vertically, for the gable end. If not, you may find that dust/dirt will build up in the ribs of the sheet as water will not easily wash them off. But for installing, you can fix the sheet via various methods:
      1. Crest fixing – you can use the normal polycarbonate compatible screw (e.g. Clearfix or OneShot) for steel. These include a cutter which cuts a 10 mm hole in the sheet as you insert the screw. This allows for expansion and contraction in the sheet.
      2. Valley Fixing – you can also screw through the valleys of the sheet. Generally speaking this is a less watertight method, but for a vertical wall this is less of a problem. A few things to note if you choose to do this. The standard polycarbonate screws that have cutters are no good. The cutters will get in the way. You MUST pre-drill a 10 mm expansion hole. you also need to take care not to pin the sheet to the frame by over tightening.

      I hope that this provides some assistance to you.


    1. Hi Rick

      Thanks for the question. All sheets will be clearly marked with a label saying THIS SIDE TO THE SUN, this is very important to stop the sheet breaking down prematurely.


  2. Can you please advise me how to cut the trim deck roofing, we have a shed and need to add on to it to protect gardening equipment?

    1. Hi Kev

      Thanks for the question.

      We can cut sheets to length for you free of charge. Simple advise us of your requirements when you order.  

      Otherwise, sheets can be cut using a fine tooth circular saw, a jigsaw, or even with a good pair of scissors (if you are only cutting small sections or the odd sheet).  When using power tools you will need to clamp the sheet as close to the end as possible to stop vibration, and it can often be easier to cut a few sheets at a time. Remember to allow for some overhang to ensure that water from the sheet will fall into the gutter and not onto your structure.


      1. Hi.,I put the infills over the purlins and screwed the sheets over it.Do you think that it will be okay ? Also I had to make a joint cause sheets too short,at a certain point I had 3 sheets overlapping each other is this okay? Thank you.

        1. Hi Martin
          Thanks for your enquiry. Normally purlin tape would be used to run across the purlins before screwing the sheets down. This helps to eliminate the creaking noise as the sheet expands and contracts with temperature change.
          The foam infills would normally be used if you are trying to seal the area against insects etc. This should not be an issue as the foam will just squash down as required. Also the overlaps should not be a problem.
          Regards Team PCR

    1. Hi Levi

      I have never hear of this being a problem… Usually the roofing sits on top of timber rafters and purlins you would need to fix the light to some of this structure. Pending the type of bulb and the heat that it gives off you may need to consider the distance from the light to the polycarbonate. Otherwise, your electrician should be able to advise you further.

      Hope this helps
      Polycarbonate Roofing

        1. Hi Asalatha

          Thanks for the question. We generally give an estimate of $35-40 per sqm for the standard polycarbonate ranges (this includes an allowance for screws). If you have the dimensions of your area we can quote this for you.

          Team PC

  3. Hi, I want to use the 10mm twin wall sheeting to enclose a balcony on a 1st floor. What are the installation guidelines with regards to wind and distances needed in between fastening.


    1. Hi Justin

      A full answer to the question would require information on your local wind rating. For standard (up to N3 rating) fixings are generally recommended at 800 centers (through the Aluminium H bars). Under high wind situations it may be necessary to place a polycarbonate roofing screw directly through the center of the sheet. IF you thin you may need – please contact us for a copy of the high wind installation guide.

      Polycarbonate Roofing

    2. Two of the 4 suntuf polycarbonate 2400mm
      roof sheets installed by my builder for my pergola seem to be sagging towards the end of
      each panel .

      1. Hi Justin

        The two most common things to check here would be:
        1. Have screws got a clearance hole? Some screws have cutters on them to drill an 10 mm hole to allow for expansion and contraction. If a standard screw is used, then this 10mm hole must be drill as an additional step. This is to allow for expansion and contraction – the sheets can buckle or bend (sag) when it’s not done.
        2. Overhang – how much is the sheet overhanging past the last purlin (support). The max should be 150mm.

        Hope this helps
        Team PC

  4. I am building a 20m x 5m carport/side verandah structure on the side of my house. We want to include some 100% block for full shade via corrugated Zincalume sheets as well as some Suntuf sheeting. Even allowing for doors, windows etc…. do you have any guidelines for the best way to produce an even diffused light effect? Is it best to keep an even spacing of Suntuf sheets (1:1, 2:1 or 3:1) within the structure, or focus more on spacing to suit windows etc… Thank you.

    1. Hi Mike

      Thanks for the question. There is no direct answer to this question other than to point out a few considerations:
      1. The more polycarbonate the more light… it will depend on the balance that you are looking for.
      2. When considering light diffusion colour plays a large part – colours like opal will scatter the light coming through the sheets and give a more even spread of light. Clear may let more light through, but you will see clear shadow lines on the ground below outlining the joining of metal to polycarbonate…
      3. Many people use polycarbonate over windows or doors to allow light to flow into other areas as needed and find this practical – it may not give an ‘even’ light to the whole area however.

      I trust this helps somewhat.

      Polycarbonate Roofing

  5. Hello, Got a problem you may be able to solve for me. I have recently replaced the polycarbonate roofing sheets (greca profile) on my pergola which hang over guttering, but I am now noticing some water creeping back up from the ends that overhangs the gutter and drop onto the floor below. Depending on the the strength of the rain it can become quite annoying. Is there a solution to stop the water creeping back and drop straight into the gutter as intended. Any ideas would be appreciated.

    1. Hi Michael

      Thanks for the question. I would assume that the gradient (fall) on the roof is a bit low. You have a few options…

      1. Increase the fall on the roof. This would require quite some effort, but it does have the added benefit of improving the ‘self cleaning’ of the sheets. This means that when it rains, or the wind blows, dirt/leaves etc are more likely to wash off the sheeting making it look more appealing. If that sounds a bit too hard…
      2. Depending on the distance from the end of your sheeting to the end purlin, you could use infills under the sheeting to stop the water creep. Obviously it will keep creeping until it hits the infill – this may or may not help. Finally…
      3. You could add a small amount of silicon to the valley section of the roofing at the very end of the sheet in the gutter. This will effectively create a ‘drip edge’ which will help to stop the water creep. If you do decide to use this option – remember the following: use a neutral cure (Polycarbonate friendly) silicon, only apply the silicon to the sheet, i.e. don’t use it as an adhesive to stick the sheet down to the purlin. It is important that you allow the sheet to expand and contract.

      I trust that this helps.

      Polycarbonate Roofing

    1. Hi Keith

      Thanks for the question.

      If I am understanding you correctly, you have a 1 foot fall for every 2 foot run (horizontal distance traveled). This would give you a fall of about 26 degrees. With a good fall like this you should not require a drip edge… the water is very unlikely to travel back up the under side of the sheet. I trust this answers your question!

      Polycarbonate Roofing.

  6. Hi, I have an old flue in my metal roof that I want to remove and replace with a clear sheet to let some more light into my living room.

    Are any of your products suitable and can you let me know how to install them so that i doesn’t leak?



    1. Hi Richard

      I assume that you are talking about a ‘chimney’ flue coming through the roof. It is not clear if the flue is leaving the roof from within the wall of the house or outside, from a patio roof. If internally… this is not usually done as there is always a ceiling under the roofing, which of course would stop any light getting into the rooms of the house… effectively just lighting up the ceiling cavity. This would normally be achieved with a skylight which effectively creates a tunnel from the roof through the ceiling cavity to the ceiling. This ‘tunnel’ keep outs heat/vermin/bugs etc from the ceiling cavity getting into the house. In some cases the cavity may be built in. This may be a consideration…?

      Otherwise, as for waterproofing… the best solution where possible is always to replace a whole sheet so that the polycarbonate would run from the flashing on the top edge of the roof to the gutter in a continuous length. In this case you can lap the polycarbonate OVER on BOTH sides of the metal. As per usual you would need to pre-drill the polycarbonate, use a polycarbonate compatible washer and screw normally through the metal sheet on the lap.

      I trust that this helps, don’t hesitate to give us a call if you have further questions.

      Polycarbonate Roofing

    1. Hi Ray

      No, like any roofing, it shouldn’t leak if it has been installed correctly. It may just mean that some of the screws have not been put in straight, meaning that the washer isn’t sitting flush and making contact the full way around. I would start by having a look at the screws.

      Polycarbonate Roofing.

  7. Hi was is the correct overlap a corner please the veranda is in the corner of the house and thus 2 sheets will overlap at 90 degrees

    1. Hi Ron

      Thanks for the question.

      With Corrugated roof sheets (or any profiled sheet for that matter), when you are working around a corner the sheets will not overlap. You will be creating either a ‘hip’ or a ‘valley’ depending on if it is an external or internal corner. In either case you would need to cut the sheets at an angle and then use a flashing for water proofing. You would be best to speak to a local metal fabricator for these flashings.

      Polycarbonate Roofing.

  8. Hi, I have a carport with a colorbond fence 1800 high, affixed to the carport posts, I need to fill in the gap at the top of the fence (about 400mm) and plan on using some clear polycarb sheeting (Suntuf greca profile, ridges will be horizontal) what is the best way to seal the top and bottom? I was thinking of using some colorbond flashing. the sheets themselves will be screwed to the carport posts using polycarb roofing screws.

    1. Hi Heath

      Thanks for the question.

      Yes some custom flashing would be the best way to seal this. Be aware that there maybe a bit of dirt/dust visible on the corrugations of the sheets as it can build up a little when running the sheets horizontally. Be sure to face the UV side out, otherwise it can break down prematurely.

      Good luck
      Polycarbonate Roofing.

  9. Do I wait to secure the top row of screws onto the roofing sheets until I pt on the ridge cap? So the ridge cap and roofing is screwed in at the same time?

    1. Hi Bruce

      Thanks for the question.

      It could be done either way, if you screw the sheets first the screw head may make the flashing sit a little proud, a foal infill usually overcomes this. If you screw them both at once you need to ensure that the polycarbonate is still pre-drilled with an oversize hole for the screw to allow for expansion and contraction.

      If you use a polycarbonate flashing you can use the standard screw with the cutter. The cutter will cut bother the flashing and the polycarbonate.

      If you us a metal flashing, you may find that you need to remove the cutter from the screw (oneshot) or find a screw without a cutter. in this case you would need to take the extra step of pre-drilling the polycarbonate sheet.

      I hope this helps.

      Polycarbonate Roofing.

  10. How do you fix the end panels to the facia when installing under a gutter. and does it matter which way the “C” section goes ie wide side up or down?

    1. Hi Ted

      The ‘back channel’ is usually pinned against the fascia with the long side on the top. It should be used with foam for waterproofing and to allow for some expansion and contraction. There are numerous ways in which you could hold the channel in place… rivet,screw into fascia a dab of silicon etc.

      I trust this helps

      Polycarbonate Roofing

  11. If you can’t walk on the polycarbonate sheets how do you climb up to fit and fix the ridge capping to a hip roof?

    Thank you 🙂

    1. Hi Michelle

      Walking directly on polycarbonate sheeting is not recommended. In situations where you need to get across the polycarbonate it is recommended that you use a “crawl board” or in other words a plank! It should span across a few of the supports underneath the roofing to spread the load. Be sure to take care not to scratch the sheets too – you can use a blanket underneath.

      I trust this helps.

      Polycarbonate Roofing team

    2. Hi thanks for ball these helpful answers
      Can you discuss purlin or batten sizes that you would recommend
      Our house has a lot of 20mm by 50mm rough sawn battens but these are not availaableb any more it seems in local large hardwares.They are light but sturdy
      Is there a recommended batten size and type of timber

      1. Hi Michelle
        Thanks for your enquiry. The size of batten/purlin is a building code issue and will depend on the wind load as to what size you should be using.
        However on saying that generally you would need a minimum of 35mm in thickness so that the screw does not protrude through the timber.
        Hope that helps.
        Team PCR

  12. I am fixing 8 Sunglaze sheets to a pergola roof. I have all the joiner sections for the 7 mid sections, but how are the sides of the two end pieces sealed?

    1. Hi James

      Where a full sheet is used you can use the joiner again. If you are cutting the sheet a few angles, one under and one above the sheet is one method. Then the angles can be screw into place to secure the edge of the sheet.

      Kind regards
      Polycarbonate Roofing

  13. Hi.. Ive just installed the roofing yesterday, and today there are cracks running the full length. These cracks are only on the underside. They are not the whole way through. I can defininately catch my finger nail on the cracks. They are on most of the ridges that i have screwed. So im thinking over tightened. But i see they are on some ridges not screwed, but i cant catch my finger nail on these oned. They look like cracks, but dont seem to be.

    1. Hi William

      Thanks for the comment. Certainly doesn’t sound right! Over tightening isn’t normally a concern (as the sheets will bounce back into place once backed-off). I think your best course of action would be to contact someone from where you purchased the product.

      Good luck!
      Polycarbonate Roofing

  14. Just a thought. On the Grandkids cubby house ( used to be our garden shed but, what do you do?) a full size gutter wasn,t needed but a cover of some description was needed along the bottom edge of roof panels so various heads weren,t cut. Ended up fitting a strip of Back Channel minus the infill and sloping it away to one end. Looks good, no sharp edges. For the limited amount of water its fine.

  15. I am roofing a pergola attached to a 2 story house. How should I seal the flashing against the rendered wall?

    1. Hi Craig

      Thanks for your question. I assume that you are using an apron flashing? This would normally be sealed with silicon in most cases. I trust this helps.

      The team at Polycarbonate Roofing

    1. Kia Ora Quentin

      Thanks for your question. Side laps are standard, that is one and a half ribs for corrugated, one rib for Greca profile and one rib for Trimdek.

      If you are referring to end laps (as i suspect you are), you are normally recommended to lap some where between 200-300 mm. This means 100-150 each side of the row of lap screws (you always need to make sure that the lap is over a support. We have covered this (with a helpful picture) in another post see the link below:

      I trust this helps!
      Polycarbonate Roofing

  16. I would like to install panels onto an existing aluminum pergola which is attached to my house. The structure has 5 rafter beams which are 2 inch by 6.5 inch set 22 inches apart supporting 48 purlins which are 1.5 inches square set 1.5 inches apart. This is attached to the house on two sides with pillars at the outside corners. The structure has no pitch to allow for water runoff. Do you think that I would be able to use your product to cover the existing structure? Keeping in mind the beams and purlins are hollow, how would you advise attaching panels to the aluminum?

    1. Hi Julie

      Thank you for your question.

      There are a few considerations here! The short answer is yes, it could be used – but there would be a few compromises:
      1. Polycarbonate sheets are either transparent or translucent – this means that you can see through them to varying degrees. This also means that you will see any leaves, bird droppings, dirt etc on the top of the sheet. One of the reasons that a 5 degree fall is recommended is for self-cleaning of the sheets.
      2. Water run off – a flat roof is much more likely to leak, hard to flash and hard to control where the water may run off – i.e. against the walls of the house!
      3. Water pooling – if the water is not running off it can pool on top of the sheet. While polycarbonate is very strong it may sag under the weight of the water. This probably won’t be too much of a consideration for you as you have lots of purlins close together – which would most likely stop possible sagging effect.
      4. You may void parts of your manufacturers warranty.

      If you did decide to go ahead you would screw in the usual way through the crest using a TEK head polycarbonate screw (such as Clearfix or Oneshot).

      I hope this helps
      Polycarbonate Roofing.

  17. Hi,
    Have just had a new polycarbonate ‘roma’ clear roof installed (about 3weeks ago), very happy with the result, but, I can see patches of residue from the removed stickers, please could you advise how I can get the sticky stuff off without marking or damaging the ploycarbonate. Worried if I leave it too long it may harden therefore making it harder to remove.

    1. Hi Caroline

      You have to be a little careful not to damage the UV coating on the sheet. Therefore NO abrasives or chemicals. Some warm water with a mild soap and a little ‘gentle’ persistence may be the best answer. Most manufactures have stickers that are designed to not leave any residue behind… Try to get to it sooner rather than later.

      Best of Luck Polycarbonate Roofing.

  18. Condensation under polycarbonate.Rafters attached to fascia with painted timber battens.fall away from house roof.Roofing starts above existing spouting with 100mm over hang and falls away from house at minimum fall to the new spouting.I am a builder an have never had a problem with condensation under polycarbonate (Tas)

    1. Hi Reijo

      Condensation can occur on all types of roofing, Polycarbonate is no different. It is usually caused by a temperature differential on either side of the sheet. It is pretty hard to control but increased air flow usually helps.

      Thanks Polycarbonate Roofing

  19. How to connect the top of the greca roof to the gutter of my house? The gutter is at a lower position

    1. Hi Js

      There are a few ways to do this, depending on where the roofing actually finishes.

      A back channel can be used to go either under the gutter or in some cases but into it. Otherwise a custom flashing going from the top of the roofing and turning into the gutter may be needed.

      Kind regards
      Polycarbonate Roofing.

  20. Is there any professional installation service to be recommended? The proceed of installation is a little bit complicated.

    1. Hi Bill

      We are a supply only company. For most products a handyman should be able to help you regarding installation.

      Kind regards
      Polycarbonate Roofing.

  21. I currently have a roof area of 17m x 8m over my pool (skillion roof) that is covered with colorbond sheeting. I would like to get some light in and was thinking of replacing some colorbond sheets with clear or tinted polycarbonate. What is the best way to fix a polycarbonate when matching it to existing colorbond shets (using one shot screws)?

    1. Hi Damien

      Once you have matched up the profile of your colorbond to the Polycarbonate its pretty easy. One Shots are good for going through the polycarbonate only sections, but where the sheets lap with metal you will need a different screw as the cutter on this type of screw will get in the way. You will need to pre-drill a expansion hole in the polycarbonate and then use a standard roofing screw with a polycarbonate compatible washer to fix.

      We trust this helps

      Team Polycarbonate Roofing.

      1. Hi, just asking about the profiles. My colorbond is 16mm high but yours is 17mm. Is that due to the thickness of the polycarbonate and are they compatible?
        Many thanks

        1. Hi Michael

          I assume your are referring to the CORRUGATED profiled sheeting – yes they are compatible.

          Thanks team PCR

  22. I intend using corrugated polycarbonate on the south facing wall of a shelter.
    Due to orientation and location, the south wall it, is likely to have sunshine on winter mornings on the INSIDE of the wall, and sunshine on the OUTSIDE of the wall on late afternoons in summer. Which side should face out to avoid UV damage?

    1. Hi Graham

      Thanks for the question. Using a corrugated sheet in this way is not advisable as it is only UV treated on one side – the sheets are all marked on one side with “this side up”. You might want to consider a twinwall like SUNLITE as it us UV treated on both sides and is probably better suited to this job.

      If you wanted to proceed with the corrugated sheeting you would need to decide which surface would get less UV and orientate the sheets accordingly.

      Thanks – Team Polycarbonate

  23. Can I Install Polycarbonate Roofing Sheets straight onto the Rafter without purlins? (Rafter about 600 distance)

    1. Hi Deiter

      Thanks for the question. Some polycarbonate systems can be installed onto rafters. For ‘profiled’ sheets it is NOT possible – you require purlins. For Twinwall or multiwall sheets – it is possible, though some are better suited than others. This will depend on the exact distance between the rafters.

      Sunlite can be cut down to suit any size.

      Sunpal has sheets with fixed widths and rafter centers of 602 mm.

      Hope this helps
      Team Polycarb

  24. Hi,

    I have recently installed the roof sheeting to a pergola. I have noticed local water build up at the end span next to the gutter. The end span sheet is sagging down and then past the last rafter (extending into the gutter) the sheeting is lipping back up. I have checked the screws and they are generally level. Would the sag in the sheet be due to overtightened screws or the end span in the sheet being to long?


    1. Hi Deniz

      Thanks for the question. There are a few possibilities here…

      1. As suggested your end spans are to large. For standard profile you will find a list of the maximum end spans listed in the second table on the linked page
      LINK HERE – table for end spans

      2. As also suggested it may also be a screw problem – there are two possible causes here:
      a. Screw over tightening. The washer should contact the sheet without causing the sheet profile to deform, in other words it should sit pretty naturally. It seems that you have check this!
      b. Not predrilling an expansion hole (or not using screws that have cutter to do this automatically) – this can also cause the sheet to buckle (normally during the hottest part of the day).

      My guess without know your profile or end spans it that its most likely to be end spans… feel free to come back with this info.

      Hope that this helps.
      Team polycarbonate.

  25. Hi
    We have installed Greca roofing over a pergola. All good except the ridge capping (Greca profile) doesn’t sit flush once screwed onto the sheets. If we take it off & put on a non profile ridge cap, what is the overhang required from the ridge cap to the sheet? Does the ridge cap come only one width? If the ridge cap doesn’t provide enough coverage is the only option to re roof with more overhang at the top?

    1. Hi Bev
      My first thought is they have screwed down too tight which is distorting the ridge cap. So might pay to check and maybe ease off a little?
      Failing that the non-profiled ridge cap does only come in one size which is 130mm each side.
      If you are worried about the cover then you could get a colourbond ridge capping pressed up to your requirements (supplied by others) and use the foam infills to seal the profile (as you could use also with the ‘flat’ polycarbonate ridge capping. Colourbond will probably work out cheaper than the polycarbonate flashings.
      I cant attach anything through this system so I will email you some drawing separately.
      Regards Judy
      Polycarbonate Roofing

  26. What type of flashing or capping do I use if running the Suntuff sheeting along a chamfer wall longways

    1. Hi Karyn

      If I understand correctly you are looking for a flashing that will be running down the length/side of the sheet against the house?
      Your best option would be to get a colourbond apron flashing. You can get these pressed up at a local sheet metal place. You can give them
      the measurements and they can make to suit. Make the width of the flashing far enough to cover over at least one
      corrugation on the sheet to waterproof. You can then seal the metal flashing to the wall.

      Thanks Judy

  27. Can I use brute flashing tape on polycarbonate to form a water tight seal or will this damage the polycarbonate?

    1. Hi Robert

      Thanks for the question. Did you mean Byute Flash…? We recommend a Butyl Rubber for sealing in some circumstances. I can see that this product is mostly made from this, however I am not sure regarding some of the other ingredients (taken from the safety data sheet). Maybe a standard flashing with some infills – to be safe?

      Team PC

  28. Hi
    I have been asked to replace all screws to an entire roof. How ever the screws supplied are a oneshot polycarbonate fixing and the existing roof sheets are tin!
    Is this still within australian standards??
    I think the customer is trying to achieve a more durable rubber but im curious because these screws dont have the second thread to help pull the sheet to the battern

    1. Hi Sam

      My main concern here would be the cutter on the OneShot screws – this is deisgned to cut the polycarbonate and isnt really suitable for metal/tin sheets. I suspect you will have no luck getting them in.

      I am not sure if it would comply with AS.

      Team PC

  29. Hi,
    Just curious if there any any issues with overlapping corrugated sheeting by more than recommended? Ie. 2-3 full corrugated overlaps? Issues with holding water or mould, etc?


    1. Hi Adam

      Thanks for the email. The simple answer is yes. It will be dependent on fall, but dirt can build up in any lap. Sometime people will do this for ‘extra’ waterproofing on low fall situations, there is no harm – but it can look unsightly.

      Team polycarbonate.

    2. Hi Adam

      The short answer is yes, you may get more visible dust/dirt between sheets. Maybe a butyl rubber could help (this is also visible, but generally better looking). The greater the fall the less the risk, are you using extra laps due to low fall?

      Thanks Team PC

  30. I have a polycarb sheet lifting on the left edge as the screw no longer holds it. The sheet is 2/3 from front edge. Is there a way to re-fasten from the inside. I cannot reach the edge in question and i dont belive the structure will take my weight.

    1. Hi Neill

      Sorry, but if I am understanding you correctly, I don’t think what you are suggesting is possible. While it may be possible to get a screw in from below, I don’t believe that it would hole for long. Any options for a stitching screw setup with a ‘grommet’ (see below image) on the end of the screw would require a hand on the top to secure… so would still require you to be on the roof.

      Screw with Grommet

      I hope this helps?

      Team Polycarb

  31. Hi just after a little bit more guidance on the back channel, foam and roofing sheet combination installation, am I correct in saying, I secure the channel to the wall, install the foam into the channel, then butt the roof sheeting up to the foam in the channel with a little pressure against the foam then screw sheets in place. Any other advice?

    1. Hi Ross, yes you have the idea. Some people will just pin the back channel to the wall using the sheet and then silicon the back channel. you may need another set of hands to help with this method though.

      Hope this helps
      Team PC

  32. We have built a wooden frame approx cover 34m2. We have 1 beam attached to a wall and 3 more cross beams running in the direction we want to put the roof sheets (width of area…. 5.5m). Our question however, how many beams do we need for support on the longer side of the structure… i.e approx 6.2m .

    Area to cover: 34m2 (5.5m long x 6.2m wide) i know we will need about 10 sheets of 5.5m. Will placing beams 1m apart in the width suffice?

    1. Hi Michelle

      Thanks for your question.

      The answer will depend on what product you are using. I will assume that because you have comments on this particular post that you are referring to a profiled sheet i.e. corrugated, greca or trimdek profile.

      If I understand you correctly, you will have rafters 5.5 m long (this is the direction of the fall on the roof) and your purlins will need to be 6.2 m long (these run perpendicular to the length of the sheeting)… see below for clarification. So you need to know what spans the purlins are placed apart

      Roof structure

      This information can be found here. Look at the second blue table – you need to look at the “Maximum Mid Spans” and “Maximum End Spans” – these will change pending the profile.

      Hope this helps

      Team PC

    2. Hi. At the overlap of each sheet, do you place an extra screw in this edge or can you skip it and keep to your screw placement in every 3 or 2 corrugations?

      1. Hi Michelle
        The overlap must always be screwed down, so no you cannot skip it. This will disrupt the 2-3 pattern so you must add an extra screw if required.
        Team PCR

  33. Hi,
    We recently installed corrugated polycarbonate roofing on our pergola but used too few screws. I’m wondering if we can get up on the roof to add more screws. If we lie across the rafters so the weight is distributed would that be ok? Ie. how much weight can they take?
    Many thanks!

    1. Hi Josie

      This can be done, the use of crawl boards is recommended. This is a plank that spans across a number of supports to distribute your weight. Be sure not to scratch the plank over the sheeting.

      Hope this helps

      Team PC

  34. Hi,

    I recently used your one shot steel screws on a metal/tin roof on the advice of a Bunnings worker. After reading the packaging etc I see these screws are for polycarbonate sheeting into steel. The screws went in fine and straight and the washers are sitting tight. What are your thoughts on this long term?

    Thanks in advance.

    1. Hi Peter

      Thanks for the questions. We are not confident on our answer to this one. In theory the screw should be ok… we were all a bit surprised that you managed to get the screws in! The problem would be that to change them you would need to consider how to manage the larger hole that the screw would have cut in the metal sheet. Maybe not worth worrying about?

      Sorry we can be of more help with this one.

      Team PC

  35. Hi, just a question, I am installing Suntuf over a pool pump and filter setup. and being only a small structure, what is the maximum length that can be installed without any support under the polycarbonate? It would only be a couple sheets wide. Screwed front and back with a slight fall?
    What is the best colour for best UV block out as there will be no sides/ walls, only a roof over the equipement?

    1. Hi Peter
      Thanks for your enquiry. Maximum span would depend on the profile of the sheet you would be using. Do you have a preference? What would the length of the span be?
      All the polycarbonate provides 99.9 UV protection regardless of colour. Different colours then reduce heat and light so probably just pick a colour that is going to match whatever you have around.

      Regards Judy

      1. Hi Christina
        Just to clarify is the flue of the wood stove going through the Suntuf sheet?
        Thanks Judy

    1. Hi Christina

      Suntuf has a long term service temperature of 100 degree C. It would depend on the flue system – but you would need to ensure that the temp stays below this. There maybe laws around this also you need to consider?

      Thanks Team PC

    1. Hi Dwane

      We cover Suntuf products in Australia – you question is probably best answered from someone in the US – they will be able to guide you on local warranties etc.

      Thanks Team PC Aus!

  36. Hi there,
    I have just installed 5 sheets on the pergola roof and 3 of them have buckled at the overlap towards the top of the panel, closest to house roof. The screws are not overtight as they are the self-cutting type. Now I do’t know if there will be leakage if it rains.
    I’m not sure how it happened but it looks terrible! Please advise.

    1. Hi Rose

      Thanks for the message. it is hard to suggest things without seeing the sheeting. The main areas of concern would normally be over tightening the screws (this can still be done with screws with cutters). basically you should be looking got good contact with the washer without deforming the profile of the sheet. Are both sheets clear of the cutter on the screw – maybe they have been caught? The other area may be making sure the sheets have been laid square – this may be why it is out on the one end more?

      Hopefully this may help. Good luck!
      Team Polycarbonate

  37. We have a pyramid pergola with thatch covering. We are thinking of ditching the thatch and replacing it with your product. But we’re not very clear as to how we would “cap” the structure at its apex. Any suggestions?

    1. Hi Alan

      This type of capping is usually referred to as a ridge cap olong each of the sides. The ‘cap’ section would probably be best to see a local metal fabricator – the would bee able to bend you something to suit.

      Team polycarbonate

    2. Hi Alan

      Thanks for the question. For this type of ‘flashing’ you are best to speak with a local metal fabricator to have something folded in metal to fit. We can also supply foam infill for most products if required.

      Team PC

  38. Hello,
    I’m building a flat roof verandah attached to the back of my house.
    Fall is 5 degrees and I’m using corrugated clear poly.
    The end wall of the house is flat continuing up as an end gable.
    The gable is fibre cement sheet, the lower part of the wall is colourbond corrugated steel sheet which will be under the verandah. There is a 600mm eaves at this end of the house .
    The main support beam attached to the house id 140mm x 35 mm Treated Pine.
    What do your recommend for sealing the poly sheets at the house end,
    Metal Back Channel 40mmx 20mm with foam infill….
    Apron Flashing ( Corrugated ) with foam infill.
    Verandah length is 6000mm ( 6 Metres )
    Obviously Metal Back Channel will be the most cost effective .
    The verandah is on the opposite side of the house to the normal prevailing weather side.

    1. Hi Laurie

      Thanks for the questions. You are correct the back channel will be cheaper option. The PC apron probably makes life a little easier as it will be flexible enough to account for the pitch. you will have a small gap behind the back channel due to the pitch – this can be siliconed for water proofing. If you get the profiled apron you won’t require the infills. There is no wrong way from what you have suggested – clearance sometimes dictates which way you would need to go.

      Thanks Team PC

    1. Hi Toni

      Would would suggest around 250 screws for this area – this equated to approx 8/sqm.

      Thanks team PC

  39. Hi, we built a timber-framed, polycarbonate sheeted roof over our deck about 8 years ago. In heavy rain water drips from the two hips. The drips appear to be coming from screw locations. The screws are those with the cutter and rubber washer. On inspection the rubber washers at most screws are severely cracked, and sometimes missing. How long are these washers expected to last? I have tried to remove a screw to replace, but with the cutter in place it is difficult to remove the screw. What now?

    1. Hi Bob

      Thanks for the message. These washers will of course deteriorate, but I have never heard of them being problematic that early. AS you suggest the best course of action would be to replace the screws, some care would need to be taken.

      Unfortunately there is no easier fix that I am aware of.

      Thanks team PC

  40. I am going to use polycarbonate roofing panels underneath my new deck to keep the area underneath dry. I do not want to use perlins, as leaves will become trapped, so I am planning to rip some pressure-treated pine with constant slope and attach along the length of the joists, then attach the panels to that. Sound reasonable? Also, joists are on 16″ centers, and the 12′ panels that I need are 26″ wide. Suggestions for how to handle the overlap?

    1. Hi Jamie

      It really depends on what sheet you are looking at using. A profiled sheet (e.g. corrugated or greca) wont be suitable – if I am understanding your email correctly. These types of sheets require the support of purlins, otherwise they will sag.

      If you are look at a twinwall like a sunlite, this would be possible. However you would need to rip the sheets down so that they join on your ‘rafter’ or timber.

      I hope this helps.

      Team PC

  41. Hi, I am in the process of designing an outdoor area in Melbourne, size being approx 8m x 8m using PC sheet (corrugated or greca) for roofing. Given the temperature range where we can have +/- 20 degrees during a 24hr period, is it ok to use OneShot screws on a sheet of 8mtrs in length or do you advise larger fixing holes. Also can I assume that if a PC sheet at 8m in length can expand by approx. 20mm @ 0-40 degrees, it will then expand by half that for +/- 20, as we would never experience a temperature variance of 0-40 in Melbourne, the norm being +/-10-15 degrees. Thanks.

    1. Hi Peter

      Thanks for the great question.
      When installing longer sheets (over about 7m) drilling an over sized hole is good practice. The OneShot screws are designed to cut a 10 mm hole. You would need to drill the sheets with a 12 mm bit, then use a ‘normal’ screw (without cutter) with a Polycarbonate compatible washer, to cover the hole. I trust this answers your question.

      Thanks Team PC

  42. I have recently installed Laserlite 3000 Grecia pattern to our patio. However I unwittingly selected too light a shade colour & consequently the light penetration can be too great particularly in bright sun light conditions. Is there a paint product available that can reduce the intensity of the UV rays and still allow reasonable light penetration.

    1. Hi Geoff
      Sorry to hear about your problem… There is nothing that we are aware of that will do this. Generally speaking painting poly sheets is not advised. Maybe you could use some shade cloth to help?

      Let us know if you need anything else.
      Team PC

    1. Hi Ken

      No more or less than any other style of roofing. It will largely depend on structure and installation. Low pitched roofs are always more prone to leaks (no matter the roofing material). When installed correctly, all of these systems should be leak free.

      Trust this helps
      Team PC

  43. I am installing the polycarbonate suntuf panels to the roof of my greenhouse. I am using the closure foam on the top, bottom and sides. The supporting cross sections going through the middle, Can I directly screw them to the wood framing or do I need the foam between the panels and wood? Thank you for your time

    1. Hi Ryan

      Thanks for the question. I believe from your email you are referring to infills. These are foam pieces shaped to suit the profile of the sheet. They are not required. A cheaper option if you did want to do something is purlin tape. This is a flat foam tape (sticky on one side). It is used to reduce creaking and cracking of the sheet as it expands and contracts. This is particularly useful if you have painted timber purlins. But again it is not required.

      We hope this helps.
      Team PC

  44. I’m having problems with mould. Is there any method of preventing this by treating new sheets or removing the mould once it has grown on the sheets?

    1. Hi Bruce

      Thanks for the question. There is no pre-treatment that I am aware of that will help to prevent the growth of mould.

      Generally, the simplest cleaning method for polycarbonates is a mild detergent with a cotton cloth or soft bristled broom (rising thoroughly afterwards). I have also attached the chemical resistance document which may guide you if your require something to kill mould. See here.

      I suspect that you are past the design stage, but a steeper fall is also useful here. Trimming any trees etc if they are shading the roof area, allowing more sunlight onto the sheets can also assist. Regular cleaning may also prevent buildup.

      We hope this helps

      Team PC

  45. Hi
    I’m am installing a suntuf clear corrugated roof including flashing.

    In regards to the flashing and attaching it to a weathertex wall am I right in assuming I have to cut a line along the entire span of flashing to put that little lip of the flashing in before I seal it with sillaflex.

    Do I then drill the flashing into the wall and then on top of the sheets into the Perkins?

    Sorry for the questions there isn’t much out there on flashing installation.

    Kind regards

    1. Hi Gabriel

      We can’t comment on the weathertex sorry! Certainly the flashing is secured to (on top) of the sheet and into the wall. If you are using any silicones be sure to use a polycarbonate friendly on (neutral cure). Were you using metal or poly flashing… metal will expand and contract less. If using poly shorter strips help.

      Team PC

  46. What sort on material (if any ) can be placed as close as possible to the underside of clear suntuf sheeting during summer season?
    Or is this something which would reflect onto underside and create probs?

    I was thinking of something thin,light in colour,low in thermal mass like fibre cement.
    Maybe even with some sort of thin insulation medium if it is do-able.
    Shade sails under the sheets is partially helpful but I think it’s an ‘after the horse has bolted’ bandaid

    1. Hi Colin

      Thanks for the question. There should be too many worries with solid products (such as fibre cement) or shade cloth etc… the only consideration is reflected UV. Depending on your sheets they may be UV treated on 1 side (facing up) which means if they are exposed to reflected UV they may deteriorate more quickly.

      We trust this helps

      Team PC

  47. What is the best way to attach the sheeting at the house end of the sheet (within the back channel) as where I am installing it, it is very windy so I want the added stability. Can you use a long pot rivet ?

    1. Hi Greg

      I am not 100% sure what you are meaning here. Maybe adding additional screws to the last purlin is the best option? Otherwise usually the sheeting would simply sit into the back channel (into foam) which could be secured to the wall.

      Hope this helps.
      Team PC

      1. Thanks for your reply, the problem I have got is that the back channel is larger than the sheeting, I got back channel for the ribbed format and the sheeting is the corrugated one and I cant exchange any of it so I was thinking of attaching the sheets some how into the back channel (against foam) to make it more secure, as the area I am doing is approx. 25 mtrs long.

        1. Hi Greg

          Ok, a little tricky! Riveting would probably not be great over time due to the forces of expansion and contraction that it will experience.

          Maybe another strip of foam to sit above the corrugated sheet – between the sheet and the top of the channel? You can get infills that would work ok – but i think it may still be loose in the back channel depending on the actual dimension!

          Hope this is of some help.

          Team PC

  48. I’m installing a new roof of 6/11 m lengths of Spandek with a strip of polycarbonate half way across. The poly is in 2/6m lengths so I need to over the 2 sheets 1/2 way along with an approx 1 m overlap (saves cutting the poly to shorter lengths. How should I seal the overlap to prevent water ingress. I’ve seen some sort of tape in my travels through the interweb, plus a mention of silicone, or a Sikaflex type non-silicone. Which is best?

    1. Hi Steve

      Thanks for the question. Silicone or Sika is NOT a good idea. Polycarbonate will expand and contract and these can damage the sheets. We recommend the use of a sealing tape (which we can supply) either side of the screw line.

      In regard to the sheet lengths, we would normally recommend trimming the excess from the sheets, this will always give the cleanest look. We can always trim these to length for you if this makes life easier.

      I have added a link to the full installation guide for your reference.


      Let us know if we can help with anything else.

      Team Polycarb

  49. Hi
    I have a corrugated suntuf roof on a pergola and need to cut a 150 mm round hole into the roofing for a flu from a range hood exhaust fan. What is the best way to do this?

    1. Hi Paul

      Thanks for the question.

      For a cut like this, you best bet would be a good pair of scissors! Start the hole with a drill is probably easiest. You will find it quite easy to cut with scissors.

      We trust this helps
      Team PC

  50. Hello
    We recently had a bad hailstorm in Sydney which has put some holes in my existing roofing. I want to replace it with a Suntuf clear polyC panels. Apart from removing old sheets and replacing with new, is there anything I need to consider

    1. Hi Shah

      Thanks for the question.

      Mostly its pretty straight forward… you may also want to consider new screws, depending on the age the washer may have also become brittle. Depending on the what the flashing is made from, you may be able to reuse it.

      Other components that may be useful are purlin tape and infill (if required).

      Remember to be careful when removing old sheet – they can be brittle. Do not stand on them.

      Team PC

  51. Can you have gyprock installed under a polycarbonate roof or are their building standards that dont allow this?

    1. Hi Catherine

      This is something you would need to confirm with your local building authority.


  52. Hi There,

    Is there such thing as lipped roof panels? normally i would use glass for roof panels and add a 70mm lip to the outer pane. is this possible for Polycarbonate roof panels?


    1. Hi Marshall

      Thanks for the question… there are some panels that have ‘lips’, though we are not sure about what you mean.

      You are probably best to seek a supplier in the UK (we are in Australia), as it seems like you are in the UK?

      Team PC

  53. Hi, I had a 3.2 x 3 m steel pergola installed in my courtyard by a builder in January, with polycarbonate roofing. It is constantly making a cracking noise when it heats up every day for nearly 2 or more hours, no matter if the sun is out or not, which is very annoying. Can you advise if this can be fixed by the builder, as its still under warranty. What should I tell the builder to do to fix the problem. Hope you can help with this enquiry. Many thanks

    1. Hi Sue

      There are 3 potential causes/solutions that we may suggest.

      1. Noise tape – used on purlins to reduce noise as the sheets expand and contract – this is usually more important on painted timber.
      2. Screws over tight
      3. No expansion hole around the screw. (not using self cutting screws or failure to pre-drill holes for screw)

      Polycarbonate will expand and contract which can lead to noise. If you think it is excessive you may want to check the above.

      Trust this assists in helping to resolve the problem.

      Team PC

  54. I need to fix my hail damaged skylights that are made with poly-carbonate Greca profile that flush mounted onto metal roof with matching profile .
    My problem that all Greca profile poly-carbonate sheets I find on-line have 76mm between the ridges, where my old roof and skylights are approximately 90mm between the ridges.
    Please advise where to find the old Greca profile poly-carbonate sheets or if they don’t make it anymore what’s the alternative

    1. Hi Mark

      I would suggest that the product you have is not Greca, but could be Spandek (metal), with the poly equivalent being SPANTUF. Please check the below profile drawing to ensure that this will match.

      spantuf profile image

      Trust that this helps?

      Team PC

  55. Hi, I am having a new pergola roof area 8.12Mx 3.6M to attach my South side backyard brick wall in Sunnybank Qld and bought 11 sheets SUNTUF STD GRECA CLEAR 3.6M. Is 11 sheets is right enough for 8.12M ? I have prepared 6 Dulux Weathershield painted purlins for 5 spans intervals , is it wasteful and too many holes on carb. roof to have 4 spans enough ?
    I read your installation guides and conclude that ; I have to bend my upper body forwards about 760mm the farthest to drill the screws in mid spans ??, it looks a bit difficult to keep the drill machine perpendicular to purlins although I am 175 tall.
    My friend told me to coil the sheet from side I am afraid it can’t be that .
    Why don’t you have a detail illustrated pictures for this?

    1. Hi Francis

      Thanks for the questions.

      11 sheets is correct for the structure width of 8.12m, each sheet has a cover of 760 mm once you account for the overlap.

      I am not sure 100% what your spans are but the mid spans on Greca profile can be 1200 mm with end spans 900 mm. If I understand you correctly your spans will be approx 900 mm – which is fine.

      In most occasions (with the use of a ladder) installation is done by leaning over.

      Let us know if we can assist further.

      Team PC

  56. I am installing a polycarb apron flashing on a pergola roof butts up against the house and does not have enough pitch. The pergola roof is metal. Will i need to predrill expansion holes in the apron flashing or will expansion not be an issue with such a small piece of polycarbonate? most of the polycarb will see the sun.

    1. Hi Ryley

      You are correct, as the pieces of flashing are generally smaller they will have less expansion. We do however recommend that you still use an expansion hole to be safe.

      Trust this helps
      Team PC.

  57. Hi I have installed 1piece of suntuf corregated polycarbonate tinted sheet in the roof to allow light into our bedroom because it is dark. There is 1 batten or Purling not sure what it’s called but the piece of timber the polycarbonate is screwed to that is visible and condensation drips at the batten. How do I stop this ? Could I use the corrugated foam infill ?
    Thanks in advance.

    1. Hi Jason

      Thanks for the message. There is no easy solution to this – it is caused by a difference in temp inside and out. I don’t believe that a foam infill will stop this.

      Maybe a piece of twinwall a little below the corrugated sheet (still lets light through) may help to reduce the chances of condensation forming on the sheet?

      Trust this helps
      Team PC

  58. I am planning to put a roof over an ‘L’ shaped verandah using Sunlite 10mm twin wall sheeting . One leg of the ‘L’ will be 4000mm wide and the other leg 1800mm. Both will be approximately 6000mm in length. The sheets will be fastened to Alyspan 100 x 50 steel patio rafters on 1000mm centres. The fall will be 5 degrees, perhaps a little better. As a hip will be created, can you tell me what is the best way to seal this?

    1. Hi Harry

      Thanks for the question. Essentially, you will treat the raked edge the same way as the top side edge of the sheets. There are a few option here pending your circumstance. Then get a ridge cap folded to suit and screw this to the h bars at each junction.

      Trust this answers your question. Give us a call if you need anything else.
      Team PC

  59. I have a pergola with laserlite sheets along the back of the house (10m length x 4m width) it is about 10 years old. the sheets are fine but since last year if found they the end towards the house has stared leaking from the gap. I assume the silicone at that end has come off sue to expansion and contraction – how can i fix this is it from under the pergola or on the laserlite sheets and can i stand on a timber sheet on the laserlite sheets – Thanks in advance

    1. Hi Edwin

      Thanks for the question. There is a good chance that you are correct regarding expansion and contraction. Ideally, silicon is not used in this method – a back channel or apron flashing is generally the norm. Fixing it is probably a hard task. Given its age it is possible that you may crack the sheets when using a crawl board. Given this the only solution may be trying to access from below?

      Team PC

  60. I am installing suntuf roofing sheets on a pergola using one shot screws. I have noticed that a couple (so far) of the screw holes have developed a small radial crack during the drilling process. I am not sure what is causing this (too fast or too slow drilling? too much pressure?) however can these cracks be repaired, say with silicone, and if they can’t be repaired are they likely to propagate resulting in an unsightly, leaking sheet?
    kind regards

    1. Hi Tim

      Thanks for the question… not an easy one to answer via internet. There is a sweet spot with speed and pressure. A mid speed is generally good without too much pressure. You need enough speed to ensure that the cutter will still work and cut itself.

      Hope this provides some help?
      Team PC

    1. Hi Tim

      Sorry, nothing that we can suggest in terms of repair… Did the washer cover the area?

    1. Hi Brad
      Thanks for your enquiry.
      While there is no adverse effects from the water collected off polycarbonate (i.e. leaching of chemicals) manufacturers will generally advise not to use due to other foreign items being on the roof i.e. bird droppings, dirt etc.
      Regards Team PCR

  61. Hi,
    I need to install leafstopper aluminium gutter gaurd over some corrugated sheets on my pergola, what would be the best way to attach the saddles that hold the mesh to the sheets?
    The saddles are tech screwed to the colorbond sheets.


    1. Hi Ant

      Maybe a stitching screw could be utilised? Someone will contact you with details.

      Team PC

  62. Hi, I am turning my shed into a greenhouse and would like some recommendations on the best suntuf roofing if anyone can please help

    1. Hi Shannon

      There are a few option. Most people will us the suntuf range of profile sheets as a cost effective way of doing this. Sometimes the sunlite can also be used – though more expensive. Thge main consideration is colour pending on what you are growing and how much light you need etc.

      Feel free to contact us if you want to talk about this more.
      Team PC

  63. I have a pergola measuring 16′ 4″ by 15′ 2″. I recently replaced the original polycarbonate roofing (Suntuf) using 26 inch by 12 foot pieces. The roofing company used the 15 foot 2 inch side to lay the sheets longways. To cover the remaining 3 feet+ they cut 4 foot sections and placed them under the 12 foot sheets. This morning, we had rain and the roof leaked in a couple of areas. I noticed that Michael (November 23, 2016) had the same problem. I read the suggestions and wish I could use the 1st option. The slope is not the greatest. Question: Can I use Loctite PL Premium 10 fl. oz. Polyurethane Construction Adhesive to stop the leaks? OR is there another adhesive I can use?

    1. Hi Don

      Thanks for the question. If I understand your message correctly, I think you have a similar – but different, problem to Michael. While we are not familure with that particular adhesive, the general advice would be NO. Polycarbonate sheets will need to expand and contract as they heat and cool so this is not recommedned. In Australia (i am also guessing that you are not from around here) we have a butyl rubber strip for waht we call end laps? maybe this is also available there? This rubber goes between the sheeets – but still allows them to move.

      I hope this is of some assistance for you.
      Team PC

  64. What is the maximum distance I can space my rafters. I will be using clear corrugated sheeting.
    This is to cover a grow site, so I need as much light as possible, and accordingly don’t want to cast shade with the rafters.

    1. Hi Sean,

      Thanks for the question.

      Corrugated panels are installed on purlins, your maximum end span should be 800mm and maximum mid span 1000mm.

      Hope this helps.

      Team PCR

    1. Hi Sean

      Thanks for the question. Yes, certainly. Infact clear polycarboante are used all over the world in commercial greenhouses. Depending on what you are growing, there are colours that diffuse the light if required.
      Polycarbonate greenhouse
      Greehouse green crops
      Polycarbonate Roofing  greenhouse Lettuce

      Team PC

  65. Hi – We have a detached pergola (used as a car park) that has a lattice “roof”. I was thinking of adding polycarbonate to keep the rain off. However, I’m discovering that to add the 5 degree drop, this will be more of a project than I realized. The pergola is about 7.3m x 7.3m. If I used NO drop, the “rafters” and “purlins” are already in place – but of course, leaves and dirt will collect on the polycarbonate. Other than needing to be sprayed off occasionally, would laying the polycarbonate flat be a real problem on a detached pergola that DOES NOT need to be truly weatherproof? (Lifetime of the polycarbonate, etc.). It also won’t look as nice, but may do the job… Thanks!

    1. Hi Dan,

      Thanks for the question! The are a couple of issues with having no pitch on your roof. As you’ve mentioned the leaves and dirt will collect on the roof as the wind and rain isn’t able to blow/clean them off regularly. Another problem is water will pool as it can’t run off and this can cause leaking or sagging of the panels. If you have a low pitch on your roof, regular cleaning is recommended. Installing the panels outside of the manufacturers guidelines may void your warranty.

      Many thanks
      Team PCR

  66. Hi there, I have to cut a hole for a downpipe which runs in one of high corners of the polycarbonate sheeting. What is the best way to seal around this downpipe to avoid water leaking through?

    1. Hi Adam,
      Thanks for the question.
      You will need to use flashing to prevent leaking around the downpipe. If you are installing a profile panel such as corrugated you could use apron flashing with infills underneath or for a flat panel you could source a custom flashing from a local metal fabricator.
      Hope this helps.

      Team PCR

  67. Hi,

    I have a 5 degree corrugated polycarbonate roof over a swimming pool, and it is great! However the overlaps get dirty and are difficult to clean. Is there any solution? I was thinking maybe a bead of silicone to stop detritus and moisture getting between the sheets . But then this would make cleaning impossible, and besides I see you don’t recommend using silicone with polycarbonate. Any thoughts?


    1. Hi Alban,

      Thanks for the question.
      You can use butyl rubber (which will be visible) between the overlaps and as mentioned it is generally not recommended to use silicone but if you do it needs to be neutral cure or non acidic.
      Hope this helps.

      Team PCR

  68. Hi, I am replacing my old fiberglass panels with Suntuf. The old panels are in the Greca format and I want to replace them with corrugated sheets. Will there be any issues with spacing or flashing? Joe

    1. Hi Joe
      Thanks for your enquiry.
      You would need to check the purlin spans on your roof to make sure they are within the recommendations for corrugated sheets i.e. end spans 800mm max and mid spans 1000mm max. If you previously had a Greca profiled flashing then of course this would not fit Corrugated profile.
      Regards Team PCR

  69. Hi,
    I’m installing polycarbonate trimdek roofing – onto recently painted battens. The roofing area does not receive much sunlight so I do not expect too much movement in the sheets. I will use the Clearfix self-drilling screw. I’ve installed a number of additional battens such that they spaced very close together. My question is if I install anti-noice tape, is it ok that I just install it on every third batten rather than every single batten (which would be quite onerous)? Alternatively, I’m thinking of not using any tape at all.

    1. Hi Craig
      Thanks for your enquiry. Polycarbonate does expand and contract and the amount of expansion will depend on the length of the sheet i.e. the longer the sheet the more expansion.
      To install purlin tape on every third batten would defeat the purpose of the tape so would be all or nothing.
      Purlin tape does help to eliminate the creaking noise as the sheet releases from the painted surface. It’s not a must just an option.
      Regards Team PCR

    1. Hi Toque
      Thanks for your enquiry. Maximum overhang will depend on what sheet you are using but the most common would be a maximum of 50mm past the last purlin.
      Thanks Team PCR

  70. Hi there
    I need to flash Greca profile sheets against a fibro gable and they will run with channels parallel to the wall rather out from it as I have seen in your diagrams. What is the best method of flashing in this case? Obviously I can’t use the apron flashing to fit into the channels, so I was wondering if I could use your barge capping to prevent leaks in this case?

    1. Hi Rob,

      Thanks for the question.

      Unfortunately we don’t have a suitable flashing we can supply in this instance.
      You will need to source a custom flashing from a a sheet metal company in your local area.

      Team PCR

    1. Hi Corey,

      Thanks for the question.

      It would depend on the product that you are using? Generally (in Australia) you can increase the roof spans by 10% for a vertical (wall) application.

      Team PCR

  71. Three quick questions:

    Context: I have a open air pergola with flat roof in warm weather (100 degrees fahrenheit or 38 degrees celcius) during summer. Planning to use the following roof panel.

    1. What do you use for fall/slope, is it wood mostly or is there a ready made strip like below

    2. And what do you use the closure strips above for? Is it mainly to seal the sheet closer to wall/flash?

    3. I couldnt find Purlin tape on homedepot, not sure if its required for this type of panel.

    1. Hi DP
      Thanks for your enquiry. As you are in the State please contact
      Phone: 1-800-999-9459
      Address: 9735 Commerce Circle, Arcadia West Industrial Park Kutztown, PA 19530, USA
      Products and installation vary from country to country so you need to check with them.
      Regards Team PCR

    2. Hi DP
      I can see from your enquiry you are located in the US.
      Please contact Palram Phone: 1-800-999-9459
      Address: 9735 Commerce Circle, Arcadia West Industrial Park Kutztown, PA 19530, USA
      for details as stock and installation varies from country to country.
      Regards Team PCR Australia

    1. Hi Garry

      Not sure what you mean by wall flashing – could this be an apron? – generally all polycarbonates will require an expansion hole. A OneShot screw will do this for you if you’re screwing through the rib/crest of the sheet. If you are screwing the pan or a flat part of the flashing you may require a standard screw with a EPDM washer – and PRE-DRILL a 10 mm oversize hole.

      Give us a call if this does not make sense.

      Thanks TEAM PC

  72. We have just replaced old (16yrs) and damaged polycarbonate roofing on our pergola. We have used 4.8m corrugated sheets with one shot screws. The fall on the pergola is just under 5 degrees and we noticed the previous installer had siliconed the overlap of the sheets. We have lived here for 6 years and up until recently there were no leaks in the roof, we could sit under in all weather. Recent hail storms changed that, hence replacement of the roof. We have fixed the sheets with a 1.5 corrugation overlap, on some sections the overlap is sitting up and there is a 5mm gap. It doesn’t appear that the screws have been over-tightened. Any suggestions to prevent water ingress other than to use silicone?

    1. Hi Gary

      Thanks for the question.

      A few things here:
      1. It may be worth checking that the screws have cut the sheet properly on the laps. The sheets should sit together well on the laps, where you have a 5mm gap makes us think that there has been a problem with the screw. I would check to make sure that the cutter has cut a clear hole in BOTH sheets and that the cutter itself is clear and not ‘pinning’ either sheet in the areas where you have the gaps. A screw that is not straight, or not been secured without enough speed may cause this…

      2. Silicon is not advised in these situations (as you have alluded to). Generally if you have a 5 degree fall and the laps look good, you shouldn’t have too much trouble. The best product to use if you are still concerned is a butyl rubber. The down side of this is that it is black and you will see it.

      We trust this helps!
      Team PC

  73. Do you have a basic certified training for installation Panels and corrugated sheeting and cold store installation according to European code ?

  74. We are considering a polycarbonate roof over an arbor under a number of large fir, pine and cedar trees. Should we be concerned about water dripping from the trees and bringing chemicals from the trees onto the roof?

  75. we are working on installation of 10mm Solid sheets but the parent material in 15mm thick section , i want to know screws that can go in to 10mm sheet and 15mm thick pipe , and hold together on top vertical open side ..?

    1. Hi Bala

      You will need to allow for expansion and contraction of the polycarbonate. In the case of screwing you would need to have an over-sized hole in the polycarbonate. If i understand your question correctly – you may need to look a a different method as you will not be able to hold them together this way.

      Team PC

  76. I’m looking to replace my pergola roof with Suntuf poly sheets, the original roof butts up against the outside face of the gutter of the house and does not have flashing (just has a bead of silicone stopping leaks…)
    Can I install C-channel and foam on the end of the new poly and butt it up against the gutter? Will this be waterproof enough?
    Or should I install metal/poly apron flashing with foam underneath?

    1. Hi Jake

      You could go either way,but the back channel (c section) is quite well suited to this situation. You could silicon the back channel to help waterproof.

      Team PC

  77. Hi, I’m using corrugated polycarb sheets as a weather barrier around the back deck (i.e. as a wall, instead of a roof). In the gap between the roof beams and the deck rails, do I need to fix the overlapping sheets together somehow (like, with a rivet), or is that unnecessary? Thanks, Brett.

    1. Hi Brett

      Generally this is not required. Rivets are not advised in any case as they do not allow room for expansions and contraction of the sheets. If you do require the laps to be pinned together a stitching screw is you best bet – you would need one specific to the application (to allow for previously mentioned expansion).

      I guess that you probably have a 1.0-1.4 m unsupported span? If so, this is probably a little over-spec for the sheets – the end spans should be no more than 800 mm… Though given its a wall you do have a 10% margin and probably less problems if your happy to push your luck!

      Trust that this helps.
      Team PC

  78. Hi we are putting a dark poly sheet over our decking. Can you advise if when standing on the deck would then look dull in colour of grey because of the darker sheet above. I am wondering if we should have a lighter sheet above for a more natural coloured light when using the deck but do need UV / heat protection

    1. Hi Chenee

      Thanks for your enquiry.

      Yes a dark colour will darken the area. By using a lighter colour it will reflect the natural light and look brighter.
      All the colours (including Clear) provide 99.9 UV protection. But the actual colour of the sheet allows different amounts of light and heat trasmission so if you look at the brochures under the colour range chart it tells you what those figures are for both light and heat.

      Regards Team PCR

  79. Hi there,

    Ill be installing a few plycarb twin wall panels to extend and existing colour bound roof. Since the exisitinfroof has its own metal fascia and a gutter, would in general installers mount the end alliminium cap to the metal fascia directly or is there a metal plate of some sort that is used as an intermediate support ?
    Ill be putting 6 panels on 1m spaces wodden rafters.



    1. Hi Arek

      Thanks for the question.

      Generally the end caps shouldn’t be fixed to the fascia. They sheets will be secured to the Rafter through the HBARs. Then flashings should be used for waterproofing.

      Team PC

  80. Hello poly roof experts,
    I’m laying out the framing for a 26×5 (feet) Suntuf canopy at a 14+ degree pitch alongside our house and plan to use the polycarbonate Suntuf wall connector (apron?) with the horizontal lap siding on the house. In order for the connector/flashing to fit correctly, what is the required distance between ridge plate and the lower edge of the siding? Any pointers for installation of the wall connector would be appreciated.

    1. Hi Peter

      Please see attached images. I suspect that these will assist with your query, though Im not sure what you are trying to ask… sorry.

      These are set size option. In some circumstance you may find it easier to have something bent up at a local sheet metal fab. To suit exactly what you need.
      Corrugated Wall Flashing APRON
      APRON flashing angle
      APRON flashing height
      APRON FLAHING tail length

  81. I have just installed new roofing sheets with a 5 degree fall, it appears that when it rains the water will leak and it appears that it leaks at all of the joints, it seems like it gets sucked under the joints. is this possible ?

    1. Hi Warren

      Thanks for your enquiry. Can you let us know what type of sheet you have installed i.e. a profiled sheet (corrugated) or a twinwall/multwall?
      Thanks Team PCR

    1. Hi Dianne
      We can supply foam infills for the Ez Glaze and then you can either use a polycarbonate ridge flashing (which we can supply) or a normal colourbond ridge (which you would need to get from a metal supplier).
      The infills will sit in-between the sheet and the ridge to stop the wind blowing any rain back up under the capping.
      Regards Team PCR

  82. unlike corrugated polycarbonate sheets trimdek has a fairly flat ridge, do they need special flat neoprene washers unlike the standard washers that have the corrugated profile? I ask because I used the latter washers and as they are not fully flat they somewhat distort the poly if too tight and seems to have gaps if too loose. I’m noticing a bit of buckling in places (all have 10mm expansion holes) Please advise

    1. Hi Joe
      Thanks for your question. The washers supplied with the One Shot or Clearfix screws are the same regardless of profile. If the sheets are buckling, especially on the overlaps, I would suggest you check to make sure the cutter has drilled through both sheets, not just the top sheet. The other thing to check would be the screws are not on an angle. And yes it is a fine line of not screwing down to tight or too loose.
      Regards Team PCR

  83. Hi there,

    How do you secure the infills at the front of the Greco profile roofing to get a snug fit? Given the flexible nature of the foam, I’m assuming you can’t screw through the foam. On the other hand I assume you can’t glue them to the roofing thereby inhibiting the expansion capability of the sheeting. Any suggestions? I couldn’t draw a conclusion from the image on the installation guide.


    1. Hi Lynn
      Thanks for your enquiry. Normally you would screw through the infill when installing the sheet.
      You could glue the INFILL to the FRAME but never to the sheet itself.
      Hope this clarifies for you.
      Regards Team PCR

    1. Hi Pete
      No unfortunately there is no profiled flashing for Trimdek profile. You would need to use a colourbond flashing and either scrib it or we do have the foam infills that you could use to seal between the sheet and apron flashing.
      Regards Team PCR

  84. Hello,
    I am planning to install the twinwall polycarbonate on my pergola with the area of 16m2. I already have the 2.4x1m twinwall polycarbonate sheets and I know how to connect the width 1m with another 3 sheets of 1m using the H- connector. However since my sheets are only 2.4m long and not 4m long, my question is how do I connect the 2.4m sheet length with another sheet to make up to 4m in length? Looks like I can’t use H connector as the water will be trapped here. Can you please advise how I can connect another sheet that runs down the gutter?
    Thank you

    1. Hi thanks for your enquiry. Unfortunately you cannot join twinall sheets in length. As you have pointed out the water would be trapped where the join is.
      You would need to purchase 4m long sheets.
      Regards Team PCR

  85. hi trying to replace damaged 5 rib polycarbonate roof on patio just wanting to know the best way to get in between the tin roof and the timber batton.

    1. Hi Andrew
      To access the sheets you will need to use a ‘crawl’ board – a plank of somesorts – put across the sheets to spread your weight. You should never walk directly on the polycarbonate sheets. You can then unscrew the damaged sheets and replace.
      Regards Team PCR

  86. Hi. Currently have old greca installed and want to replace with corro. It is a simple curved roof. Chord 3600. Height 500. Need to know sheet lengths please. Is it long enough to curve? Is greca or corro better for curving?

    1. Hi Graeme
      Thanks for your enquiry. Corrugated and greca have the same cold curving radius which is a minimum 4m. If the chord is 3.6m and the rise .5m then this is actually outside of the miniumum radius at approx 3.5m so would void warranty on the sheet. Over a chord of 3.6m the maximum rise would be .42m to be within guideines.
      Regasrds Team PCR

  87. G’day, is it possible to curve a flashing? We have a curved section over our front door which is currently covered by (what looks like) perspex. It is in need of replacement and I think it’ll be easy enough to lay a sheet of polycarbonate lengthways over the existing frame. One end of the sheet will need to connect to a brick wall. Currently the gap between the edge of the perspex and the brick is filled with silicon – it’s OK but not ideal. Any suggestions would be appreciated.

    1. Hi Callan
      We only supply polycarbonate flashings in ridge, barge or apron so these would not be suitable for you.
      You may need to get a colourbond flashing curved to suit the application.
      Or if you decide to use silicone just make sure it is a neutral cure/non-acidic so it doesn’t damage the polycarbonate sheet.
      Regards Team PCR

  88. I have an alfresco roof section of poly carb sheets in a gable arrangement, ever since the Melbourne golf ball hail damage of Christmas day 2011, having had all the poly carb and clear ridge cappings replaced under my home insurance, the section of poly carb roof leaks when it rains around the ridge line areas.
    The clear ridge capping is a flat style profile, I am of the opinion the water is making its way under the ridge capping and working its way down along the underside of the roof sheets
    Is there a way I could rectify this problem?

    1. Hi Maurice

      I believe that you require an infill. It is a closed cell foam that sits between the flashing and the roofing for waterproofing. We will need to know what profile sheeting you have, contact us at and we can assist further.
      Team PC

  89. Hi there, I’m in Canberra, can you tell me where I can purchase the ridge capping in Greca solar grey? I have purchased the sheeting but can’t find the capping in this colour. Thanks

    1. Hi Steve
      Thanks for your enquiry.
      Unfortunately Ridge cap in Grey is not available. The only option in the polycarbonate is Clear or you can use a standard Colourbond one if you prefer (which we do not supply).
      Regards Team PCR

  90. Hi guys,
    How do you recommend installing flashing around corners?
    I have a square column which the corrugated sun turf has been installed around.
    The installers just used silicon but it has deteriorated, is looking shoddy, leaking and I need to make it water tight again.
    Many thanks

    1. Hi David

      Thanks for the question. If I am understanding you correctly – the best way to do this would be with APRON FLASHING and or a PAN flashing (up hill of the column).

      You will need to get something bent up to suit.

      Team PC

  91. i have a 4 mr long wooden wall running alongside my pool. The wall has almost reached its use-by date and i am thinking of replacing it with a steel framed wall clad with either colorbond sheeting or suntuf sheeting which is the preferred option. I read that the uv protection is only on one side of the suntuf sheeting. Does the other side of the sheeting need some sort of protection from the sun?

    1. Hi Lindsay

      Thanks for the question. You are correct, some polycarbonate sheets only have protection from UV on one side. This means that if you expose the non-protected side to UV it can cause the sheet to breakdown prematurely. This can happen with walls or where UV reflects off another surface. Generally all ‘profiled’ sheets (Corrugated, greca or trimdek) are UV1 (one sided protection), most twinwall, multiwall and solid sheets are UV2 (both sides protected).

      Trust this helps
      Team PC

  92. I have a flat pergola 6000mm wide and would like to install a curved roof. Question I’m having difficulty finding an answer to is the minimum curve centre height. A curve does not have a fixed pitch and any information always talks of maximum, not minimum.

    I would like to have a maximum height at mid-span of 230mm to minimise graded batten sizes.
    So question is what is the MINIMUM base-to-apex height for a compliant curved roof using corrugated profile?

    Thanks in advance. Jason

    1. Hi Jason

      Thanks for the question.

      With regards to the minimum height for the curve – you should be looking to maintain at least a 5 degree (average) pitch. If we understand your question correctly, the ‘chord’ will be 6000mm (referring to the image below)
      Curved polycarbonate roofing

      In this case the minimum ‘height’ (referring to the image above) should be AT LEAST 263mm.

      There are of course maximum limits too – this has more to do with how well the sheet can curve – in your case you have plenty of ‘wiggle room’.

      We hope that this helps. Feel free to give us a call if you have further questions.

      Team PC

  93. Hello,
    we are looking to line the underside of poly sheeting to block out the light. I am looking at using roof sarking. Do you think this will have any effect on the roof sheet integrity?
    Regards shane

    1. Hi Shane
      Thanks for your enquiry. I don’t think the sarking will have any detrimental effect on the polycarbonate but you may get a build up of water/condensation between the two.
      Not sure how that would effect the sarking? You may need to make sure it can escape.
      Regards Team PCR

  94. it appears to me that all fixing to sunlite/ sunturf twin-wall polycarbonate sheeting is through the accessories but not onto the sheeting itself ? Is it possible to screw fix through the sheeting, directly onto the timber joist below? also because of my existing pergola profile and size , I am intend to lay the twin-wall sheet (with the channels ) running left and right instead of top and bottom. Any foresee problem and suggestion?

    1. Hi Hanh
      Thanks for your enquiry.
      You are correct – under a standard install the twinwall sheeting is held down by the gasket/H Joiners/F sections. It’s best to avoid putting a screw directly through the sheet as once you put a hole in the sheet it becomes an entry point for water to seep in. If you do need to screw the sheet directly, the hole needs to be oversize to allow for expansion and then you need to be very careful to seal the screw hole to make it water tight.
      Installation with the sheets and joiners running left to right is NOT an option. The gasket/joiner will create a lip which means the rain will be running down the sheet and into the gasket. The cells in the sheet and the joiners should always be running top to bottom with the fall/pitch of the roof.
      Regards Team PCR
      Regards Team PCR

  95. Hi there. Can you tell me which colour after the clear let’s in the most light please? Also in regards to heat and it being too hot, would you recommend using the clearest for a large pergola (approx 94 square metres) ?

    1. Hi Catherine
      Thanks for your enquiry. Generally we would not recommend Clear for an area you are wanting to sit under. However you need to weigh up your situation i.e. how much natural shade do you have? How much direct sunlight will you get? How high is the roof? How much ventilation – is the area open to the breeze or enclosed on the sides? It may be suitable in certain areas.

      What type of sheet are you looking at using? Profiled sheet i.e. corrugated, twinwall, multiwall etc? Link below to the website
      If you have a look at the type of sheet you want then look at the brochure/colour charts for that product, that will tell you the light and heat figures as per colour.
      Regards Team PCR

    2. Hi Catherine
      Apologies for the late reply your enquiry has just popped up in our email today.
      We wouldn’t recommend using Clear over a large area. But on saying that you would need to consider your situation i.e. how high the roof is, is the area well ventilated, does the area get a lot of natural shade?
      These can all influence the colour choice. If you look at the brochures light and heat transmission is shown for each colour. After Clear generally it would be the Opal, Cream or Diffused Ice.
      Web page link for the different options
      Regards Team PCR

  96. What is recommended for patching/repairing/sealing small holes located in the valleys of the polycarbonate suntuf roofing panels? More specifically the roofing was originally fastened using zinc-plated truss head screws without washers (i.e. the wrong screws) in the valleys of the panels instead of at the crowns. To minimize the amount of damage to the substructure that is sure to follow if left this way, what would be recommended as a possible permanent repair assuming panel replacement isn’t an option?

    1. Hi Bailey

      Thanks for the enquiry. There is no recommended way to patch sheets in this manner.

      Pan fixing is not the standard but is sometimes done. Maybe, the screw can be replaced with an appropriate screw with polycarbonate washer – the sheets will need to be drilled 10mm holes.

      Trust this helps
      Team PC

  97. Hi, if we need to stand on top of the installed polycarbonate sheets as a working platform to do some rectification works above the polycarbonate roof, is this ok if we lay down some plywood boards? What would the weight/load limit be?
    Note that the polycarbonate roof is about 14 years old.

    1. Hi Alex

      You should NOT stand on polycarbonate sheets. The manufacturers state ‘crawl boards are required to spread the load and need to cross at least 3 structural points’.

      From a practical point of view – pending what the sheets are and their condition you may need to be careful not to cause damage to them. Given their age this is certainly possible.

      Team PC

  98. Hi,

    I am looking to install approx 4.2m long corrugated sheets on top of an existing frame which only has 195x145mm rafters, no purlins are currently installed. For some reason during the original installation the rafters weren’t spaced evenly and some of the spans are up to 1600mm between rafters whilst others are only 1000mm.

    I was thinking of installing steel or aluminium roof battens like these across the rafters to act as the purlins and spaced at your recommended spans. Can you confirm that the only issue from your side is the spacing of the purlins for the end and mid spans and I just need to confirm with the batten manufacturer that their product can withstand the 1600mm gap? Given that the battens are built to take tiles or roofing sheets I would imagine polycarb sheets shouldn’t be an issue!

    1. Hi Ben

      Thanks for your enquiry. Yes you are correct. It’s fine to install the sheets onto metal purlins as long as the spacings for the purlins are within the required maximums. The spacings can be found on the brochures
      and will vary depending on the type/profile of sheet being used.
      Regards Team PCR

  99. Hi guys.

    I am installing a Greta profile sheet to an existing stand alone pergola. The entire roof actually sits within a deep (230mm) fascia on all 4 sides. It starts close to the top on one side and about half way down on the other (in to a box gutter). I am happy with fixings and spans an fall etc.

    My question is about trying to flash it at the ridge and sides. I don’t really have enough of a vertical surface on the fascia to flash it properly. Could I use a back Chanel and foam insert to all three sides? Any other ideas?

    1. Hi Tim

      Thanks for the question. I believe that best practice would be a ‘parapet flashing’. We can supply infills for the top edge to help waterproof under this. This type of flashing would need to be bent to specs by a local sheet metal fabricator.

      Trust that this assists with your question.

      Team PC

  100. I’ve a pergola that surrounds one side of the corner of the house. How do I cover it with polycarbonate sheets at the corner?

  101. Hello,

    We are designing a verandah and want it to have the polycarbonate roofing on the entire verandah however we have two valleys. Do you create custom and/stock polycarbonate valley flashings? Can you provide any guidance on how to detail the valleys using polycarbonate?

    Many thanks.

    1. Hi Sarah

      Thanks for the questions!

      Valleys are fine. There is no standard of the shelf flashing that we have available for this. We usually recommend a custom Colorbond flashing to suit your length, pitch, colour etc.

      The finer details change may change slightly pending the product being used… please contact the office if you require further info.

      Team PC

    1. Hi Tony

      Yes, all screws should have expansion holes. They will of course require poly style EPDM washer to suit. This is the info advised in Australia, I would not expect that it would change for SA.

      Team PC

  102. Hello,
    I have a 476sf aluminum patio structure attached to my house, though between roof and patio I have a 3½” gap × 25′ in length with fireplace, and patio roof mounts obstacles to go around thus can’t be one piece.
    Also both sides 12′ long vertically that need waterproofing wind blows rain in probably need 2/3 sheets each side, again vertical will still allow water in unless the flashing I’ve been reading about would take care of this?
    I am curious if you have non corrugated/or flashing to cover the gaps on vertical installation for the 3½” gap being I read not to use corrugated horizontally for wall type installation, I believe because of dust etc.
    I need to attach the 3½ gap to aluminum patio structure and galvanized gutters to have water flow into gutters instead of my patio area, though it’s kinda curved a little bit hoping this material is a little plyable.
    I am literaly stuck on stupid how should I go about this?
    The 12′ sides will be easy at top of roof/patio though bottom will be dirt/cement patio slab not sure was going to do some brick/stone blocks for seating though same issue with attaching how could I make this work? I am a decent diyer though haven’t ever drilled or used cement bolts, I will if needed first time for everything, just first time somewhere that won’t be noticeable lol 😆.
    Thanks ahead of time for any input, or materials I could use, as far as between seams on both applications.
    This is all jumbled so I hope you understand what I’m trying to do.
    I’ve tried plastic but to thin and didn’t last, now tempted to use boat vinyl if all else fails at least for the 3½ gap.
    Thanks again 😊,

    1. Hi Barbara

      Thanks for the questions. It sounds like you have a fly-over style roof, and you are trying to waterproof the gap.

      The Sunlite range (twinwall) maybe something to consider. Its not normally suggested to run it horizontally, but in cases like yours (if we are understanding correctly) it may give you the easiest option.

      Hope this helps.

      Team PC

  103. Hi,
    I am looking to install polycarb sheets on an existing pergola frame which looks to have about the main rafters at a 2-3 degree slope. Part of the frame has existing polycarb sheeting which appears to function correctly when it comes to getting rid of water – no issues with leaks or pooling I can see. I note the recommended slope is 5 degrees. Because I will be introducing purlins on the frame section that doesn’t have sheeting I have the ability to increase the slope further. Normally I would use just 70x35mm timber – my question is over a 3m section in one area and a 4.2m section in another area can I put deeper purlins e.g. 90x45mm at the top of the slope to increase the slope some more? I know the sheets can be curved slightly but I don’t want it to look like too much of a “step change” at each purlin as it’s not a curved roof profile. Note that at the bottom end I could put the end purlin flush with the rafters so I could go to 70x35mm for the mid span purlins and then 90×45 (or deeper) up the top.

    Also note that if the main reason for the 5 degree slope is cleaning, all roof areas are accessible for occasionally getting up there and using a water pressure cleaner etc to remove any leaves and debris etc.

    1. Hi Ben

      Thanks for the question.

      Yes, graded purlins can be used. Generally they would need to be gradually graded down to match the desired fall. Just to clarify – you would NEED intermediate purlins to support the sheet also – at varying heights.

      Alternatively EZ-Glaze can go to 3 degrees and can be used for a RAFTER ONLY install (if they are 600mm centres and no wider than 50mm).

      Please note that you should not walk directly on Poly sheeting – you would need to use a ‘crawl board’ spanning at least 3 structural supports. With this in mind always consider that the steeper the pitch the less cleaning required.

      Team PC

  104. Hi, I want to bend standard suntuf sheets , but rather than convex in a typical curved roof, I want to go Concave. I am guessing the principles are the same. What is the maximum ‘height’ from a chord of 3.2 m …?
    Thanks in advance.

    1. Hi Lester

      Thanks for the question!

      Suntuf has a minimum cold bed radius of 4.0m, so with a chord of 3.2m the max ‘height’ would be 0.3339m (refer to the image below):
      Cold Bend Radius - important terminology

      Maybe pointing out the obvious… but some consideration of the practical ‘fall’ will be important here, i.e. the orientation of the sheet to ensure water run off.

      Give us a call if you need anything further.

      Team PC

    1. Hi Eric

      In most cases custom colorbond flashings are used. These can be provided from your local sheet metal fabricator.

      Hope this Helps
      Team PCR

  105. Hi There,

    Suntuf 92770 Polycarbonate Plastic Horizontal Closure Strip, 2′ L x 1-3/16″ W x 7/8″ H

    Can you supply this strip to install laserlite.


    1. Hi Jafar

      This product is not stock in Australia. There is a foam version – usually used for waterproofing purposes. Feel free to give us a call if you need further assistance.

      Thanks Team PCR

  106. Hello, I’m looking at installing on a pergola that is flat. Do you have any advice on how best to create the 5 degrees Fall necessary? I was thinking of installing a timber step to drill in to to artificially create the Fall necessary.

    1. Hi DJ

      It depends on the product that you are planning. Stepping the purlins down is sometimes done. Otherwise for a rafter only installation and raked rafter can be used also. Might be best to consult a builder for some advice here.

      Team PCR

  107. Hello, I recently had a contractor build me a deck with pergola with the clear corrugated panels on top. To get enough height and slope, the pergola sits on top of some roof risers that are attached top of the roof, with maybe a 1 foot gap between the roof and the pergola (for air flow). I live in a valley that gets very strong winds, and when that happens, the panels rattle and creak with every gust. I was unable to sleep because it is right outside my window. I’m wondering if this is to be expected? Or could this be fixed? I know we don’t want to overtighten, but I would love to somehow secure the panels down even more so they don’t rattle with strong winds.

    Or, if this is what would be expected given the material and the openness of the pergola, is there a different, more solid/sturdy, clear roofing panel you would recommend?

    Thank you

    1. Hi KC

      There are potentially a few options that may assist with this. There are purlin tape or infills that can be put under the sheets with may assist in reducing any noise the maybe created. Otherwise, you may want to look at screwing every corrugation on the top edge.

      Hope this assists
      Team PC

    1. Hi Gary

      Assuming that you are talking Corrugated or Greca then yes this is fine.

      Let us know if you have any other questions.

      Team PC

    1. Hi Lyn

      We don’t have a lot of experience in this area… it is possible… keep in mind that polycarbonates are quite flexible and can scratch… but are extremely strong…

      Team PC

    1. Hi Frank

      Thanks for the question, all the polycarbonates that we sell are warrantied against hail – there are limits pending the age of the sheets and size/velocity of hail. Warranty information can be found on the Installation and Download tabs for each product page.

      As polycarbonates are exposed to UV over years they do become more brittle making the more susceptible to hail damage.

      Team PC

  108. I need to replace 2 sheets of 33 y.o. rusted-out, colorbond corrugated iron, verandah, seafront location, salt-zone 1, know I’ll never get a good colour match so wish to use polycarbonate. Do they both have the same corrugation profile?

    1. Hi Gordon

      Yes standard corrugated iron will match corrugated polycarbonate. I have attached the profile drawing HERE for reference.

      Let us know if you need anything else.
      TEAM PCR

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