Suntuf Sunlite Twinwall Installation guide and tips

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Suntuf Sunlite Twinwall Installation guide and tips

24th May 2017

See the official installation guide for Suntuf Sunlite Twin wall here,  or read on for a few other tips and tricks for planning and installing Suntuf Sunlite Twinwall Polycarbonate Sheeting.

Planning your structure

All roofing materials require some structure to secure the sheeting to. Suntuf Sunlite is no different.

The support structure for roofing purposes has it’s own terminology. Rafters run in the same direction as the sheeting, and purlins (battens) run perpendicular to these – see the image below. Sometimes the purlins will finish flush with the rafter so that the roofing sits directly on both. In other cases the purlins may sit on top of the rafters.

Suntuf Sunlite Twinwall can be installed onto supporting structures in two ways:

1. On top of purlins.  When your structure has purlins, fixing screws are placed through the Sunlite Joiners and screwed into the Purlins to hold it in place.

2. On Rafters only.  Normally there are no purlins in these designs.  H-Bar Joiners will sit on top of the rafters giving a clean appearance.  For this to be possible the rafters must be set apart to exactly the same distance as the joins in the sheet, which requires careful planning if you are building a new structure.  If your structure is already built and the rafters are the wrong distance apart, you can either put in purlins or cut the sheets down to fit to the rafter centres.  See the image below where the aluminium joiners are hidden by the rafters.

If you are building the structure make sure that you allow for a good fall or gradient. This is the slope on the roof that helps. the rain to run off into the gutter. The MINIMUM recommended fall for Suntuf Sunlite is 5 degrees. This is important for a few reasons:

1. It helps to keep your sheets clean (they will clean themselves with a good rainfall).

2. It helps with waterproofing – getting the water to flow where you want it to and not build up or go where it shouldn’t.

3. It stops water from collecting inside the sheet which can lead to dirty and mouldy sheets.

Selecting the right sheet

Once you have decided that a twinwall is the type of product that you are looking for, the next thing to do is select your colour.
Some colours will let more light or heat in, others will be darker and cooler. As a general rule, where you have light you will have heat – so sometimes you will need to compromise on what is more important to you.

Check out the table here to see the light and heat transmissions for each of the colours.

How it fits together

Sheets – The sheets are 10mm thick and 980mm wide, once they have been joined together with the aluminium Hbar and gasket they will be 1000mm (1m). Sheets are available from 1.5 meter to 9.0 m long

Hbar – Aluminium sections that are used to join the sheets together along the sides. They also provide a point where the sheets can be secured with screws. Under normal conditions you don’t screw into the the sheet – instead all fixings are secured through the aluminum sections.

Gasket – a rubber gasket is used between the sheeting and the HBar – this is for waterproofing and allowing the sheet to move within the aluminium framework during expansions and contraction.

Vented End Cap – Aluminium sections that are used to cap off the open ends of the sheets.

Lock Cap – used to hold the vented end cap into place.

Breathing and sealing tapes – used for protecting the ends of the sheets.

F Sections – Used to secure the edges of the sheets in most cases.  The ‘tail’ of the F can point down if it runs along a rafter or point up if sealing the top end of the sheeting.

Other items include:

Two Piece aluminium H bars – a few things to consider here:

They are more fiddly to put together as they have a foam on the bottom and a wedge on the top to seal the sheets in place. Both of these have to be added to the H-bar prior to installation.

They are harder to install if you have a structure with a purlin design

Polycarbonate H Joiners and End Caps – a few things to consider: They don’t provide a good water seal and may leak.  They are also not suitable for windy areas or roofing appliacations.

Installing the Sheeting

Read the complete installation guide here.


Finally, you will probably want to add some flashing to your area to weatherproof the sides of your new roof.  See the pictures below to understand the flashing involved.

105 thoughts on “Suntuf Sunlite Twinwall Installation guide and tips

  1. Hi
    I am going to make a verandah with entire roof to be sun tug greca solar grey polycarbonate. I would like to know this is good or not. If not I love to receive the ideas or commences about this.

    1. Hi Doan

      Thanks for your question. This is a hard one to answer – so i will give you a few things to consider when choosing roofing.

      The question we most get asked is around light and heat… generally people want to let light into an area but reduce the heat. When considering this you should look at the heat and light transmission figures available in the table here:

      You will also need to consider the structure that you have in place. This type of roofing will require purlins. You can see what purlins are here:

      With the greca profile the end spans should be no more than 900 mm with the mid-spans no more than 1200 mm.

      We trust that this help you!

      Team Polycarb

      1. Hi, Rick here and I’m a DIY enthusiast…
        Can this product be used as a wall on the end of a decking area to fill the void and create an indoor / outdoor Type of feel?
        I will be framing up the end area to ensure adequate support for the sheets, similar to if placing this product on the roof…!!

  2. Hi, do I need to use a dust tape on the ends beneath the end caps and do I use the rubber gasket on the edge panels that slot into the F channel?

    1. Hi Brett

      With the Sunlite system only the H Joiners use rubber gasket. The F sections and End caps slot directly onto the sheets.
      The dust tape is not required.

      Thanks Judy

      1. Hi Judy,

        the installation guide recommends taping the ends to prevent moisture and insects to get into the twin wall sheets. Which method is now the best to use?

        1. Hi Chris

          Which product are you using? The Sunlite doesn’t recommend taping the ends (in the Australian installation guide), however the laserlite Twinwall (formerly sold as Makrolon) does.

          Hope this helps. You can download the installation guide from each of the product pages, here:

          Laserlite Twinwall

          Thanks Team PC

        2. Which twinwall sheet would have better thermal benefits? The 8mm or 10mm? Thank you. Im looking at using inside glass windows up high in odd shape feature windows to reduce heat in summer. Hopefully!

          1. Hi Chris

            In a twinwall or multiwall sheet the thicker sheet will have a better U value (insulation).
            Team PC

  3. Hi there,

    I have a rafter only pergola frame. The rafter centres are 1000mm.

    Would it be possible to use the twin wall sheet without purlins?

    I have 70mm fall in 1m.



    1. Hi Matt
      Sunlite Twinwall is designed for rafter centres of 1m therefore eliminating the need for purlins unless you are in a high wind area. If using F sections on the 2 outside edges then the distance from the middle of the last internal rafter to the outside edge of outer rafter should be 995mm.
      It is recommended that you have a minimum of 5 degrees in fall which is 88mm per m so you are a little under the minimum recommended.
      Regards Judy

  4. Hi. I’ve constructed a Pergola using Twinwall Polycard Sheets. I’ve used the F section in the ‘up’ position underneath an existing gutter. Unfortunately, when the gutter overflows (which is common in Queensland, Australia) I’m getting water behind the F section and the header beam and into the Pergola room. To stop this water I’m intending to install some aluminum self adhesive tape as apron flashing to seal underneath the gutter between the vertical wall and the pergola roof. Could you recommend a product? Would 150mm x 10m Consolidated Alloys Weatherproof Byute Flash be suitable? Geoff

    1. Hi Geoff

      We are not sure if this product is compatible with the Polycarbonate itself (you do need to be careful with some chemicals). Maybe you can seal it to the top “tail” of the F section in this instance?

      Thnaks Team PC

  5. Hi Team PC.

    Very good advice, aside from a possible chemical reaction I think the glue would have been far too strong for the Polycarbonate, so I used the 100mm Byute Flash product on the top ‘tail’ of the F section. Works a treat. Thankyou. Geoff

    1. Hi Greg

      Thanks for the question. No, generally for higher wind applications the one piece system is preferred, for two reasons. Firstly, the profile width on the one piece is 65 mm (compared to 50 mm on the 2 piece), this means that there is more sheet engagement in the H Bar. Secondly, the is no way that the single piece will come apart, we have seen the 2 piece joiner do this. Depending on the wind loading it may be necessary to secure the sheeting using additional method – the installation guide refers to screwing through the middle of the sheet into a purlin.

      I hope that this answers your question.

      Thanks Team PC

  6. Hi I’m just wondering how well silicon will adhere to the twin wall sheets ? I’d like to use it as a divider in an aquairum so l need to silicon it to the glass. Thanks

    1. Hi Glenn

      Yes, normally we would recommend a neutral cure, or polycarbonate friendly silicon. Normally we would recommend this due to expansion and contraction of the sheeting – but in your case may work.

      Thanks Team PC

    2. Hi Glenn. I have purchased all the materials to close in my patio. Not the roof. Sides only. I really don’t know how to put it all together. Can go to a website,that will help me. Cheers

      1. Hi Geoff

        We are not sure who Glenn is…. but if your looking for an installation guide you can find them on our website.

        Give us a call if you cant find what you need and we can email one to you. We would need to know what you have bought!

        Team PC

  7. Hello,
    Just a few questions regarding installation, on the protective plastic it tells to install VU side up , this is printed on both sides , is there a certain side that has to be facing up ?

    1. Hi
      The sheet is actually UV protected on both sides so it doesn’t matter which side faces up.
      Thanks Team PC

  8. Hi there PC
    Please could you advise me on recommeded LOSP purlin dimensions as I may have to fasten to them

  9. Hi, im using the one piece H bar with rafters spaced 1m apart and the plan is to meet underneath the gutter. I have 17mm spacing between the top of the beam and under the gutter so it is hard for the F section tail up. Would it be ok to seal with the tape and run the sheet into the gap hitting the fascia and sealing above with silicone? So top end will have no capping

    Kind regards

    1. Hi Jonathan

      Great question. In these circumstances the use of the F section is not simply too hard to install (without taking off the gutter – which could be an option). As it would be mostly protected, i would probably lean towards sealing up the end of the sheet as you suggested. You should always try to leave a small gap from the fascia to allow for sheet expansion. You could look at using end cap to help seal the ends of the sheets too.

      Using silicon like this is usually not recommended – as it will interfere with the expansion and contraction of the sheet. you may be better off using some foam for water proofing!

      I trust this help. All the best

      Team PC

  10. I am doing a 16mm poly roof 9 mitres long is it possible to join 3 x 3 mitres sheets together on ends with out leaks on a low pitch

    1. Hi David

      Thanks for the question. Generally, while technically possible it is NOT advised to join any twin or multiwall sheeting along the fall. In practice it is too hard to waterproof and keep the sheets looking clean. The only way that this maybe achieved is by altering the structure and adding a step. This would mean that each section of roof would fall onto the one below it and there was physical gap between panels.

      9.0 m sheets are available in a range of products and while harder to handle and work with, probably preferable in this case.

      Hope this helps
      TEAM PC

  11. Hi
    I already have a 3600 mm wide roof, which I am going to have to extend another 600 mm. A one piece sheet would be ideal using it crosswise from the underneath the end of the existing roof. I know it’s not ideal, or recommended, however it would make the job a whole lot easier, and visually ok in this case. Is it possible to seal both ends to avoid moisture, dust get into the inside of the panel?
    Kind Regards

    1. Hi Laz

      As you point out this is not the recommended way of doing it. We certainly know that sometimes, costs and ease dictate what actually happens… Yes, sealing the sheets would be a good idea. Make sure they are clean and DRY before you seal them… You could add some silicon to the open ends of the sheet for the purpose as a work around.

      Hope this helps
      Team PC

  12. Hi,

    I have a pergola with rafters 650 apart. I live near the coast so it can get windy. Can I use the H bar for each rafter and not put in the purlins? Can I cut the sheet up to fit 650 width?

    1. Hi Peta

      Yes, what you are suggesting is possible and actually an advantage for higher wind areas… The down side is the waste from the off cuts of sheet.

      Trust that this helps, thanks

      Team PC

  13. i am intending to butt twinall sheets up to custom orb steel sheeting on a pergola[ free standing] . any suggestions about how to seal it well at the butted joint?thanks James

    1. Hi James

      Thanks for the question. There is no straight forward answer to your question.

      Basically… it maybe a lot easier to lap with a polycarbonate CORRUGATED sheet to match what you have on your pergola already.

      Otherwise, if you wanted to use the twinwall, you would need to use some aluminium extrusions to ‘picture frame’ the sheet and then seal & flash between the metal roof and the Aluminium extrusions to waterproof. Depending on how you are planning to place the twinwall sheet you may need to think about where the water goes as it runs down the corrugated sheet and hits the edge of the twinwall… You may need to flash back to the high side if its not running the full length.

      Hope this helps
      Team PC

  14. Why Sunlite system doesn’t require rubber gasket at F sections and End caps but laserlite does require rubber gasket? Without gasket, I afraid water can penetrate through F section and water can drag and wet through the bottom panels.

    Laserlite provided plenty nice drawings. Their End (C) and internal (H) channels has an isolated room for fastening. I think this will give us a better guide where fastening won’t punch through the poly panel and water can flow internally if leak through fastening. However, Sunlite doesn’t provide drawing for their F sections. In their installation guideline, the sketch of their F section didn’t show any isolated room and require (995 from edge to first centers). So, I feel the fastening can punch through the panel.

    The length of the panel can be up to 9m but joiner can be up to 7m or 6m only. So, some internal purlin requires two fastening. What is the minimum edge spacing for the joiner and how could we seal the joiner together to prevent water penetrate between two joiners? Gasket can be long as 25m but it could cover the side of panels but no the center of joiner.

    At last laserlite provide wind capacity tables but Sunlite did not provide any tables. Does it mean Sunlite is a cheap and nasty product where laserlite provided better quality?

    1. Hi Chun

      Thanks for the great questions and comments! We are always happy when people take time to read the installation guides and consider what will work well for them. I can answer a few of your questions below:

      You are correct – Laserlite product use more gaskets and Sunlite less. They have different methods of dealing with waterproofing.

      As you have correctly described, when installing the Laserlite Multiwall it is recommended to cover all four edges with a gasket to seal and assist with waterproofing. The Laserlite also utilises sealing and breathing tapes on the open ends of the sheets to help seal the ends. Generally, we refer to this type of system as a ‘closed’ system, trying to seal up the sheet everywhere. When installed correctly this provides a good barrier and clean, waterproof sheet. It is important to ensure that all gaskets and tapes are cut fit snugly during installation.

      The Sunlite system use less gaskets. The Sunlite can be generally described as an ‘open’ system. The aluminium end cap is a ‘vented’ piece it has holes in it to allow the movement of moisture and air. There are no gaskets or tapes used to seal the ends of the sheets. Please see the below picture for clarification:

      Sunlite VENTED end cap

      The F section, used on the barge edge does not require a gasket. It is a snug fit onto the polycarbonate sheet. There are little ‘teeth’ on the aluminium section for waterproofing. In our experience, this system also works well and does not leak. See below image.

      Sunlite Barge F section Detail with screw position

      It is important to note (as you have done) that the sheets should not be screwed directly. This is why both systems have aluminium sections to hold the sheet in place, which allows for expansion and contraction of the polycarbonate sheets. All screw will go through the aluminium ONLY. Please note that to screw the F section into place the screw should come from the side (as per above image – see red positioning). Therefore there is no penetration of the sheeting.

      Both Laserlite and Sunlite systems have sheets that are longer than the aluminium extrusions – meaning that when using long sheet they will need to be joined. When joining an aluminium section a simple butt joint is fine. With a neat square cut there is a very minimal gap that could be waterproofed with silicone (aluminium only). It is important to run the gasket the full length of the sheet in one continuous piece – this is true for either system.

      Where you have a purlin or batten design any joins in Aluminium sections will need to be over the purlin.

      Both systems have published data sheets that address wind loadings (which are similar) – give me a call or email if you require these for either/both systems. Generally speaking (using standard installation) neither of these products is best suited to high winds areas. If you are looking for a product with high wind loading capacity you may wish to consider some of the other products on our website which may be more suitable.

      Both of these products are quality. They have both been around for a long time and are covered by very good warranties. They simply use different methods for their recommended installations. There are pros and cons associated with each. Please feel free to give us a call if you to discuss these in more detail.

      Thanks again for the thoughtful questions!
      Team PC

  15. Our new home (1970’s) has a polycarbonate roofing like this one here. We want to use your product to replace the existing roofing which has now gone a bit mouldy due to holes after a large hail storm.

    What is the best way to remove the old polycarbonate panels, and do you recommend we use brand new fittings between the panels too?

    1. Hi Amy

      Thanks for the questions. Usually they will need to be removed starting from one side. You will need to be careful – old polycarbonate can be brittle and you can go through them – don’t walk on them!

      Depending on the age and the fittings it is possible to reuse some of them any aluminium bars usually clean up pretty well!

      WE trust this helps

      Team PC

    1. Hi Daniel

      An alum blade on a drop saw is best, most blades will cut however. Failing that a jigsaw or hacksaw will also do the job.

      Team PC

  16. Hi, the area where I wish to install the roofing only has a 3 degree fall. Will this preclude me from using the product?

    1. Hi John

      All polycarbonate sheets are recommended at a minimum of 5 degrees. We do advise that when using any ‘hollow’ sheets (such as sunlite, laserlite multi etc) that this is adhered to. There are products that are better suited to lower pitches.

      With the hollow sheets the problem arises if water gets into the internals of the sheet it will not get out (due to low fall) and will become unsightly over time.

      Normally, we would suggest a profiled sheet, or a solid sheet. While the guides will still recommend 5 degrees we know from experience that they are less problematic. Feel free to give us a call if you wish to discuss further.

      Thanks Team Poly

  17. Hi, After about 15 years I am due to replace 10mm twin-wall sheets on my pergola as there are several small holes through the top layer only.

    The existing system has a poly-carbonate ridge capping which worked fine although I had to put a join in it. What do you recommend for ridge capping of the roof that has 16.4 degrees slope either side ?

    Being a pedantic engineer it seems that, at the H-sections, the sheet will sit slightly higher than at the F-section due to the thickness of the rubber gasket. Is this correct ? It has some bearing on my next question.

    Do you have any recommendations on filling the gap between the sheet and the purlin ? I did use some sticky backed foam but it has crept out in several areas and become an eyesore. I may try without it next time but don’t know if there are other consequences apart from giving spiders homes.

    Given that the sheets will attach to purlins spaced at 900mm I believe that the H-section aluminium is the only choice for joining the sheets since the 2-piece system is not as strong and would be difficult to close in the unsupported parts between purlins. Do you agree ?

    1. Hi Russell

      Thanks for the well thought out questions!

      As for ridge capping, there are polycarb version available, however many people do use custom colorbond flashing. This way they can be bent to the exact required angles & lengths.

      You are correct the sheet will sit about 1-1.5mm proud due to H bar/gasket when compared to F section. If using the F section on the barge side, you can account for this by adjusting before screwing off.

      The gap between the sheet and the purlin does not require any filling… there are nil consequences (apart from potential homes)!

      You are also correct with the 2 piece system (generally we don’t love the 2 piece anyhow) – it becomes a 2 person operation on purlins one below supporting the H bar to bang the top piece in! There are some benefits to the 2 piece H system, however, in most cases the one piece is easier to use and more secure, making it the better option.

      Trust this helps!
      Team PC

      1. Thanks for the comprehensive replies. It is refreshing to deal with someone who knows their stuff and doesn’t skip things. I thus don’t have any more to ask at the moment.

  18. Hi

    What is the recommended minimum size for rafters for “rafters only” installation to attatch to the structure your 2.4 m long, 8mm SUNLITE Multiwall Polycarbonate Sheets?

    Thank you for your professional assistance and best regards


    1. Hi Richard

      Thanks for the question – however, there isn’t really a minimum size, this is really a question for your builder as it is more of a structural question (taking into account local wind loading, codes etc).

      Hope this helps
      Team PC

  19. I’m using your SUNLITE Multiwall Polycarbonate sheeting as part of the roof and wall cladding for the pool equipment storage area. This is not a normal rafter – purlin roof but a welded steel frame. I’m not able to use your f-section or any of your other fasteners so can I put screws through the sheeting to secure them straight onto my steel frame ? I will be using the double sided tape too between frame and sheeting but I’m afraid this tape alone is not strong enough to hold the sheets in place.

    1. Hi Peter

      Thanks for the questions.

      You can screw directly through the sheets but please note a few things; Firstly, it’s not ideal as it call all water ‘access’ to the centre of the sheet – which over time can make it look unsightly. Make sure that your screws go in straight and that there is a good seal between the washer and the sheet. Secondly, you will need to pre-drill an oversized hole around the screw to allow for expansion and contraction.

      I think you will run into trouble using double sided tape…

      Hope this answers your questions!
      Team PC

  20. Hi
    I have a twin wall polycarbonate roof over an existing verandah that is well passed its prime and I would like to replace it with same, as in suntuff, the existing one has a run off bend about 300mm from end, can suntuff be rounded off to provide the same profile and does this need to be done professionally or can a very handy, very experienced diy possibly manage it?
    Many thanks in anticipation.

    1. Hi Lucy
      Thanks for your enquiry. I take it you are talking about the sheets being bullnosed at the ends? If so the answer is no – polycarbonate cannot be bullnosed.
      Some companies do heat bend the twinwall (so not a DIY job) but this would void the warranty.
      Regards Team PCR

  21. Due to restrictions in our gated community we are not allowed to roof our battened pergola. Is it possible to locate the polycarbonate roofing under the rafters. (Cutting them to size and using the u chanels to keep them in place between the rafters?) thanks

  22. I have 9 sheets of 10mm twin wall poly sheets at 2meters long. I am using the H section one piece joiners. My question is can I do away with rafters and perlins over the 2 meter and screw the top and bottom ends of the H section only. The H section appears to be very strong and ridged.
    Walter Zammit

    1. Hi Walter
      Thanks for your enquiry. Although the aluminium joiners are sturdy, you will still need either rafters at 1m centres OR purlins at maximum of 1200mm spacings. So for a 2m span you would need to add 1 mid purlin.

      Regards Team PCR

  23. I am building an attached pergola style roof over my back verandah. It will have hips and valleys, and will join the existing building at each end. Imagine an ‘L’ shaped building, then, instead of the verandah roof simply extending in a single plane from one of the walls, imagine that the verandah roof line is also L shaped, so the two together create a square. So I will have a hip on the outer fall, and a valley on the inner fall (which feeds into an existing drainage point), and at either end the verandah roof abuts the building walls, with the fall of the verandah roof running parallel to the building walls. I assume that where the verandah roof runs along the building wall I can use an F section tail up, with either flashing over the top or a silicone seal between the F section and the wall. What I don’t know is what to do at the hip and valley: I am going to end up with a triangular section of sheeting at the bottom end of the hip fall and valley falls, so how do I fasten off this edge? Basically, how do I deal with hips and valleys in a twinwall rafter only installation?

    1. Hi Lee

      Thanks for the question.

      The F Section can be used against the wall if desired. Though it should NOT be fixed to the wall, as you will need to allow for some expansion and contraction of the sheeting. You will also note that pending your pitch it angle away from the wall. It can be used to create a drip edge that you can flash over.

      For the hip it is recommended to use the F sections on either side with the tail pointing upwards- then flashing over the top.

      For the valley, the end cap is used (as per a normal gutter end) all sheeting should be secure using H bars (joiners). You may need to cut the tip of the triangle and add a small section of H bar to make sure you get good hold down.

      Trust this helps – let us know if you have any other questions.

      Team PC

  24. Hi Team PC,
    I want to install on a pergola with the downside facing the house so will drain into existing gutter, in other words, sloping up from the house.
    Do I just use the same end cap and lock cap as you would for a downward sloping pergola? Also, is this a bad idea for a west facing structure for wind purposes (in Adelaide which is classified as not a high wind area)?
    Many thanks,

    1. Hi Matt

      This is not uncommon, and is fine with this product. End cap locks will still be used at the gutter end of the roof.

      Generally, the direction of pitch is of little consequence (for loading). You may want to look at the wind loading data at the back of the brochure.

      The only other consideration is the sun -western facing with an high side gives the afternoon sun more opportunity to ‘angle in’?

      Hope this helps!

      Team PC

  25. Hi there,

    We have purchased the Suntuf Sunlite 10mm Twinwall sheeting and can’t find breather tape anywhere! Do you stock this and can we purchase this from you?

    Thank you.


  26. Hi! I want to replace an existing Twinwall pergola roof with Suntuf Sunlite. The pergola frame is 3.5 x 3.5m. Can the polycarbonate sheets be cut lengthwise, for example four 3.5m sheets cut to approx. 870mm wide to fit with the H Bars and give four even-width panels measuring 3.5m total width? Thanks!

    1. Hi Patricia

      Thank you for the question. Yes the WIDTH of the Sunlite sheet can be cut down to change suit your rafter centres (approx. 870mm). This will need to be done on site.

      Team PC

  27. Hi
    I want to use the 8mm sheets to cover the gap between my existing patio and fence.
    The area is 10mtrs long and 1300 wide at one end, tapering to 900 at the other end.
    I will need to join 17 sections of the 8mm sheets and I’m wondering if the 8mm Polycarb H Joiners will be strong enough?
    I have good anchor points for the top & bottom end caps.

    1. Hi Brian
      The rails will be too far apart – recommended maximum spacing for the 8mm Sunlite is 850mm (depending on wind load) so you would need to add a mid rail for support.
      Regards Team PCR

  28. I have installed the 10mm twinwall with rafters at 1000mm ctrs. Awesome product and looks and performs amazing. I am looking at wanting to install a cast iron fire place. Can I flue through the sheets?

    1. HI Adrian

      Thanks for the question – I’m afraid its very hard to give a straight answer. Most polycarbonate products will have a service temp of around 100 degrees Celsius. There are many factors that will determine the temperature of the Flue at the point where it passes through the roof… it would need to remain below this temp.

      Hope this assists
      Team PC

  29. Hi I wish to run my multiwall sheet horizontally as I’m attaching to a window awning 900mm long is it ok to run horizontally

    1. Hi Mark
      Technically no it is not as it is against the manufacturers install guide. The problem is if the sheets gets any moisture in it, could be through condensation, the water will not run out and then you can get mould inside the sheet which will look ugly. If you want to do it that is your call but just be aware of the possible problems.
      Regards Team PCR

  30. My question is a simple one I HOPE! I need to directly screw the twin wall panel onto aluminium purlins. Water proofing is not an issue as this is in internal ceiling application. What screws and method to use to insure that the screw head does not penetrate or leave a dent the panels?
    Any advice or help available please?

    1. Hi Julian

      You can use any screw that is suited to your structure. However, we would still recommend pre-drilling an oversized (10mm) hole for each and every screw. This allows for the sheet to expand and contract. Usually you would use an EPDM washer to go over this larger hole. As for not denting the panels – this will require not over tightening the screws – the EPDM washer assists with this.

      Team PC

  31. Re the twinwall product, Bunnings shows the product with a sealed bullnose at one end. Is the end cap still required?

    1. Hi Geoff
      Thanks for your enquiry. The sealed ‘bullnose’ edge is the SIDE of the sheet not the end i.e. top or bottom. The sheet still needs to be sealed as per the installation instructions. If you need a quote for supply of all materials email us with your details, size of area etc, on the ‘request a quote’ link on the website.
      Regards Team PCR

  32. Re the accessories (e.g., H-Bar and Edge Bar), where can we view the colour options? Is there a best colour to go with the Clear multiwall sheets? The frame of the vergola is monument. Thanks!

    1. Hi Marvin
      Thanks for your enquiry. The aluminium for the Laserlite Multiwall system is available in Mill (raw aluminium), powdercoated Black or White or Anodized Aluminium. You would be able to see samples at the warehouse so let me know
      what State you are in and I can let you know the address.
      Regards Team PCR

  33. Is it possible to install this roofing onto an aluminum structure? We are building and are getting aluminum unroofed pergolas. Our builder said he can prepare the structure to allow for roofing in the future. We would like multiwall so would like to know if there are any other considerations (beyond pitch and width of rafters) we should be aware of to assist us with planning for this. The pergola might be a L shaped – hopefully this doesn’t add to much complexity.
    Thanks so much.

    1. Hi Steve
      Thanks for your enquiry. Yes the sheeting can be installed on either timber or metal structures. Once you decide what product just have the rafters installed at the correct centres to suit the sheeting.
      You will find this information on the product/installation instructions on the website. As with any celled sheet, minimum pitch of 5 degrees is important. If you have an L shaped area you will end up with a hip or a valley in the corner. The builder/installer will need to supply the suitable flashings for this.
      Regards Team PCR

  34. Hi
    I have clear corrigated roof sheet, they drip with condensation on cold morning’s.
    If I replaced them with your twin wall sheets would I still get the condensation raining on everything on a cold morning.


    1. Hi Paul
      Thanks for your enquiry. Twinwall sheets may improve the situation but unfortunately doesn’t mean you want get any condensation.
      I will email you a sheet with some info.
      Regards Team PCR

  35. We are installing Sunlite Twinwall and the installation manual says to apply the breather tape at the top and sealing tape at the bottom, however the instructions on the sheets themselves (on the protective plastic that you peel off after installation) state the opposite: that the sealing tape is at the top of the sheet and the breather tape is at the bottom. I feel the latter makes more sense as it enables any moisture to make its way down the sheet and out, whereas the sealed lower end will not permit air or moisture to escape.
    Can you please confirm what the right installation method should be?

    Will any moisture trapped in the sheets evaporate over time? (We had wet weather upon delivery)

    1. Hi Nicole
      Thanks for your enquiry. I have confirmed with the manufacturer that the instructions on the film are not correct.
      Please follow the written instructions on the installation guide – see attached page 6 refers – so Breather at the TOP and Sealer on the BOTTOM.
      Regards Team PCR

  36. Hi, I am wanting to install polycarbonate over a deck but it will only have a fall of 3 degrees. Can you advise what is best product to use please. Thank you

    1. Hi Joanna
      Thanks for your enquiry. With all polycarbonate it is recommended you have a minimum fall of 5 degrees. This allows adequate water run off and helps with self cleaning of the sheet.
      If you only have a 3 degree fall then the recommended sheet would be Ez Glaze which is a 3mm solid sheet. Link attached for your reference:
      Email us if you would like a quote for supply.
      Regards Team PCR

  37. Hi,

    Had our Twinwall installed recently on rafter set up.
    There is leakage from the H-bar with gasket fitted on several areas along the rafters.

    What do you advise in this case?

    Please reply directly to my email address thanks.


  38. Hi There,

    I would like to use the twinwall product to enclose the end of our gable alfresco. Do you have specific installation instructions for vertical install?

    1. Hi Jono

      There is no specific installation guide for a vertical installation.

      However, just think of it as a very steep roof – all the same rules apply!

      Give us a call if you have any other questions.

      Team PC

  39. Hello Team,
    I have a pergola that I want to roof in twinwall. the pergola is segmented with an upswept angle. Due to the geometry I calculate there will likely be a very slight curvature across the width of the sheet, maybe a couple of mm. Will this be a problem. Also the end sheets will need to be cut at an angle to the length. Again any issues with this.

    1. Hi Geoff

      It maybe worth considering a 2 piece H bar for this circumstance, pending the angle involved. A one piece HBar requires pushing on from the side. Again, pending the angle it can be done but can be tricky. You would need to be very careful not to ‘kink’ the sheet.

      A rake cut on the end of the sheet is not a problem in most cases.

      Team PC

  40. The rubber gasket in the H joiner channel is tight with the sheet inserted. I had to do it on the ground rather than on the rafter. What will make rubber sit on sheet neatly & slide easily?

    1. Hi John

      Apply the gasket to the sheet and push into the bar. If your having trouble, a spray bottle with water and a little dishwashing liquid can assist in reducing friction getting the gasket into the bar.

      Trust this is useful
      Team PCR

  41. Hello, I have a 2 x dome roof patio’s that I want to re-sheet with suntuf, I would like to enclose the end of the Patio, Is there anything you recommend following the radius of the 90 degrees join or do i need to get special flashing made. Also do you have any recommended installers I am in Perth.

  42. Hi, installing some twin wall pc sheet on a greenhouse. Should the UV side go on the outside as you would for a pergola or should it go on the inside to let more uv in for the plants?

    1. Hi John

      All of the twinwall that we sell are in fact UV2 – this means that they have UV coatings on BOTH sides – it will not matter. Regardless, (we are not plant experts) we understand that UV is not required for most plants to grow – they rely on other parts of the spectrum.

      Team PCR

  43. Hi Team PC
    Can you please tell me which H section is stiffer, the one-piece or two-piece? I was planning to use twin walled PC along the sides of a carport, approximately 1.5 sheets in width running horizontally along the carport. I was going to use H section at the very top, which is attached to timber for the entire length, then an H section for the join between the top and bottom rows. The top row is a full width sheet, the bottom row 1/2 width sheet. I was going to use H section along the bottom to give it some rigidity for the sheets between the carport posts.



    use H section at the top

    1. Hi Steve

      Thanks for reaching out with your question.

      This is a good question – we are not entirely sure of the correct answer… the one piece bar is 65mm wide while the 2 piece is only 50mm width.

      Some more observations regarding your plan:
      1. Twinwall sheets are not meant to be run horizontally… the risk being that if water/moisture gets inside the sheets it will not clear out (with the help of gravity)
      2. H bars are considered ‘non structural’ the maximum they would normally span between structural supports is 1200mm
      3. The 2 piece system requires banging together – this can prove difficult when there is nothing behind the underside of the H-Bar as they can flex, making it difficult to engage.

      Give us a call if you want to discuss further.
      Team PC

  44. Hi,
    I’m looking to sheet a 1.4m wide lean-to at the side of our house. The roofing will join up to a painted timber facia that is roughly 60mm below the underside of the gutter. Would a heavy-duty mastic be of ok to seal the joint or is a type of apron flashing needed/preferred?

    1. Hi Dirk

      Preferred option would be an apron or Back channel (C channel). Many ‘mastic’ style product are not compatible with polycarbonates.

      TEAM PCR

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