Laserlite Installation Guide and Tips

We have one of the most extensive range of polycarbonate products in Australia. Our team of experts are second to none and can advise you on the best solution for your project.

Laserlite Installation Guide and Tips

16th Jan 2023

Laserlite Installation Guide and Tips

Laserlite sheets are easy to install.

But it’s always helpful to have a few extra tips to make the job even easier and make sure it’s done right.

So, we’ve put together the ultimate Laserlite Guide for you! It’s the Official Laserlite Installation Guide (linked below) + a few extra tips we’ve gained over our 25+ years experience as roofing consultants. 

You’re welcome! 🙂 


Laserlite Corrugated, Greca and Trimdek sheeting is designed to be installed at a minimum pitch of 5 degrees. This means that the sheet should fall 88mm vertically for every meter horizontally, as a minimum. 
Having more pitch can be beneficial in keeping maintenance to a minimum, as the sheets will naturally ‘self-clean’ better in rain.


There are a limited number of Laterlite polycarbonate flashings available. And clear polycarbonate flashing is the only option.  For this reason, Laserlite polycarbonate roof sheets will often be paired with colourbond flashings.  As the pans of Laserlite polycarbonate can not be turned up to assist with waterproofing, closed foam ‘infills’ are available to be used with flashing to ensure that you can achieve a waterproof finish.


Purlin tape (sometimes called noise tape) can be used under Laserlite polycarbonate sheets.  It sticks to the purlins to reduce the creaking and cracking that occurs as the polycarbonate expands and contracts.  Purlin tape is particularly recommended for painted timber structures.

Back Channel is a Colorbond C section used with a closed cell foam at the top edge of the sheet to assist with weather proofing when installing the sheets against a wall.  The foam allows for expansion of the sheet.  This is particularly helpful when there is a tight clearance for the end of the sheet (often under an eave). 


As Laserlite polycarbonate sheets expand and contract as they heat and cool, an oversized hole is required for each screw. This allows the sheets to move during expansion and contraction.  These holes (usually 10mm in diameter) can be drilled with a drill prior to screwing. Alternatively, the ONESHOT branded screws available with Laserlite products will cut the hole as the screw is driven in, saving time and effort.  This type of screw is designed to be used in the CREST (high part) of the sheet.


laserlite Installation Guide and Tips - Screw info


Generally, you need to be cautious using silicones on polycarbonate products.  There are two main reasons for this. The first is that polycabonate sheets will expand and contract a lot more than other materials. This means that silicones often don’t last and can sometimes damage the sheets as they tear apart. Secondly, some silicones are not compatible with polycarbonates.  If you need need to use a silicone on Laserlite polycarbonate it must be acid-free or neutral cure.

How many sheets?

Laserlite sheets will have an effective coverage of 760mm in width. This allows for the overlap between sheets already. 
For example, if you you have a structure that is 8.0m wide, you need to divide 8.0 by 0.76m.  This would mean that you need 10.53 sheets. Which of course means you’ll need to round up and order 11! 😉 

We can help you work out sheet coverage. Contact us for a QUOTE.


We offer a free cutting service when you order your Laserlite polycarbonate sheets. If you are cutting on site, a fine tooth circular saw is the recommended method.  If you only have a small amount of polycarbonate sheet to cut, you may find it easier to use a solid pair of scissors or sheers.

Structure and spans

Any Corrugated, Greca or Trimdek sheet must be installed on purlins (sometimes called battens).  These will run across the sheet.  

Roofing Terms for quoting

The distance between the purlins are referred to as spans. In normal conditions, spans are broken into end spans and mid spans – see below image for reference. 
It is important not to exceed the spans below.  In high wind areas these spans will need to be smaller.  The spans can be found in the official installation guide (linked below).

Purlin spacings for Laserlite Polycarbonate


Always store Laserlite polycarbonate sheets flat and in the shade. The sheets will usually be delivered rolled (like a cigar). It’s ok to keep them rolled if you are doing your job in the next few days (but make sure they are stored in the shade, not left out in the sun!). Any longer and they should be stored flat. Make sure that they remain dry and are never stored wet.


Cleaning is best done with warm soapy water, rinsed off thoroughly. Don’t use abrasives on the sheets as they will scratch.


Be sure to read the Laserlite Installation Guide in full. It outlines the step by step process of screwing the sheets to your structure.  If you have any further questions about what is required to install your Laserlite polycarbonate sheets to specification, don’t hesitate to contact us. We’re here to help!   

If you are looking for a QUOTE on Laserlite polycarbonate sheets you can fill out the form here and we’ll get back to you.

24 thoughts on “Laserlite Installation Guide and Tips

  1. Hi,

    I hope you can help. We are being told it is OK to drill a hole through the body of the Laserlite mutiwall and screw through this hole to a rafter below with silicone to prevent water ingress. This is in addition to using the ‘H’ bar system.

    Frustratingly we are now experiencing water collecting within the body of the panel and dependant on the day the heat causes the waters to bubble and whistle.

    can I ask for your professional report as to if this is an acceptable practice as we have seen that other panels not dissimilar to yours ‘Ampelite’ make is very clear that every effort should be made to avoid fixing through the sheets.

    Your help and advice would be greatly apprecaited.

    kind regards
    Chris Slaughter

    1. Hi Chris

      In some circumstances you can screw through the sheet directly into the structure below. This is normally only recommended in a high wind area and if possible other methods are the first port of call, as you have mentioned. This hole is usually recommended to be 10mm in diameter to allow for expansion and contraction. Generally speaking we would usually explore other products which may be better suited to these applications.

      However, silicon should NEVER be used to seal around the screw. In this case a bonded washer is recommended.

      Feel free to give us a call to discuss.

      Team PCR

  2. Hi
    Could you please tell us is it possible to grow a ornamental grapevine under a polycarbonate roof please.. Our deck is 4/2 mts north facing. We really just need the protection from the rain in the winter but still won’t the grapevine in the summer. I would love your opinion please..thank you Helen

    1. Hi Helen

      Yes, this should be fine. We are not experts in plants, however, polycarbonates are used all over the world in commercial greenhouses for growing all sorts of plants.


  3. Hi.
    When using laser lite on a new deck roof, is there any requirements to say you need to lay wire netting or similar under neath it for safety reasons?

    1. Hi Wade

      Thanks for the question. Generally, for domestics purposes the answer is no – this may change of the roof height is over 3m. It is best to check with recent Australian standards to confirm.

      Thanks Team PCR

  4. We have had a new polycarbonate roof installed We have continuously called plumber back for leaks Leaks at the over lap of sheets He has replaced screws and adjusted screws but now wants to use silicone as a barrier between the sheets to fix the problem We are not sure after reading that silicone should never be used and also we wouldn’t be able to clean when it gets dirty We have been reading and see that there should be an overlap of 2 -3 corrugations We have 1

    1. Hi Michael

      Thanks for the question.

      So the assumption is that all of the screws are straight and that the is a good seal with the large dome washer…

      Normally, a single corrugation is sufficient for overlap. This assumes that you have a minimum 5 degree pitch! Often these sort of leaking problems are caused by low pitch. Corrugated roofing is not a great profile for low pitch applications for this reason.

      If you are dealing with a lower pitch then adding extra lap may assist, otherwise we usually recommend a butyl lap sealing tape rather than silicon. Silicones must not only be compatible with polycarbonate, but often dont allow for the expansion and contraction of polycarbonates, hence the tape recommendation.

      Let us know if you have any questions.


  5. Hi there
    Just wondering if you have any advice on how we can stop water dripping through from the gap between the end of the laser light sheets and top eave on the house. I think the sheets may have been installed with not enough overlap so the rain drips through to the ground underneath.
    We are placed the foam corrugated product in between but still a problem.
    Can you apply a silicone to further support the foam product or any other advice ?

    1. Hi Brad

      usually the foam infills do a good job at waterproofing in these circumstances. maybe an additional ‘apron’ style flashing may assist…? Its hard to say, maybe email us some photos and we will see if there is anything that stands out the we can suggest.

      Team PC

  6. Hi there,

    We have a new roof installed by a builder. But it creaks something terrible in the wind. How can we stop this from happening?


    1. Hi Hetty

      Probably worth checking that the sheets have been predrilled with 10mm expansion holes. Noise is usually related to expansion and contraction rather than wind. The installation guide describes how they should be screwed down.

      Otherwise, purlin tape (noise tape) can assist in reducing noise.

      Give us a call if you have any further questions.

      Team PCR

  7. I am searching google for advice on the expansion of 8 meter long laser lite corrugated roofing. Over that length expansion will be significant. (I plan an opal colour) I guess a larger than 11mm hole would be obvious. There is the option also of making end lap joins with shorter sheets using the butyl tape but that is just asking for problems I suspect.
    I suspect installation at moderate temperatures may “centralise” expansion?
    I cannot find any guidance. Long skylight sheet runs appear to be used in factory roofs or is that another type of product?
    Regards, Ashton

    1. Hi Ashton

      The max expansions rate of polycarbonate is 3mm per 1000mm. It will expand and contract based on temp, so moderate temps will give you some midpoint…

      In practical terms, a larger hole is advisable one sheets start getting above around 7m in a single length. Transportations is another consideration of course… as longer lengths are more expensive to move and handle. As a general rule, use a single sheet where possible, but as you have stated they can be joined if required.

      Let us know if you have any further questions.

      Team PCR

  8. Hi, Is it recommended to install the sheets hard up against the wall, when covering a pergola which is mounted off a wall ?

    1. Hi Ange

      There are a few standard methods for this, pending on type of sheet:
      1. For corrugated sheets – a back channel can be used. This is a Colorbond(R) C section with a closed cell foam insert. It allows for easy waterproofing and tolerates the expansion and contraction of the polycarbonate.
      2. Leaving a small gap and sealing with an apron flashing. Aprons can be purchased in polycarbonate, or more commonly folded in Colorbond(R).

      Let us know if you need anything else.
      Team PCR

          1. Hi Ange

            This will be ample. The max expansion is 3mm/1000mm, it wont all be in that direction also. Make sure you have oversized holes for the screws too.

            Team PCR

  9. HI I have had Laserlight roof installed , it is 4 mts long, how much fall should this have ? they have 90mm fall in the 4 mts. Thanks

    1. Hi David

      All Laserlite products are recommended to have a minimum pitch/fall of 5 degrees. This equates to 88mm fall/drop for every meter in horizontal distance… so a 4.0m long roof should have a minimum fall of 352mm!

      I hope this helps!

      Team PCR

  10. Hi ,
    Can you tell me where I can get uv protected washers. My first laserlite project came with black washers and these are still going strong. My next project came with grey washers and 5 years ago I replaced the washers because they disintegrated , they have now gone again and are leaking water.

    1. Hi Laurie

      That’s quite unusual. We can supply washers, swapping them over can be tricky pending the age of your roof and the types of screws you have. Feel free to give us a call if you need washers.

      Team PCR

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