Laserlite Multiwall Installation Guide with Tips

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Laserlite Multiwall Installation Guide with Tips

12th Mar 2021

See the official Laserlite Multiwall Installation Guide here,  or read on for a few other tips and tricks for planning and installing Laserlite Twinwall Polycarbonate Sheeting.


Laserlite Multiwall will require some structure to support the sheeting and aluminum joiners.

Laserlite multiwall is only recommended for RAFTER INSTALLATIONS (see image below) – here you cannot see the H Bars from below as they are sitting on top of the rafters.  If you are using rafters only, the rafters should have 1070 mm from the centre of one to the next. If you have rafters that are closer together you can still use this design – but you will need to trim the sheets down to suite the spacing.

IT IS NOT RECOMMENDED for Purlin design (see second image below) – here you can see the red smaller purlins running across the rafters – the rafters hides every other H bar, so you can see some H bars in between.  The H bars will be screwed to the purlins.

If you are in a high wind area chat to us about what can be done.


The main design feature that is often overlooked is PITCH – a good fall on your roof will help in a number of ways.  Firstly, it helps to keep the roof looking clean. Because you can see through it, it is particularly worth thinking about.  Secondly, it stops any moisture from sitting in the sheet.  This can lead to the sheets becoming dirty inside – making them look bad. Thirdly and finally it helps with waterproofing!

The minimum recommended pitch is 5 degrees – this equates to 88 mm of fall (drop) for every metre in length of the sheet.  For example, a 4.0 m sheet will need to be 352 mm lower at the gutter end to achieve adequate fall to keep the sheets looking good!


One of the most common questions we get is about light and heat transfer.  This will come down to the colour that you choose.  Click the table HERE to see a comparison of the colours available. The rule of thumb is that the more light you have – the more heat you have.  Sometimes it will be a conflicting priority.


The sheets are 10 mm thick and 1050 mm wide, when installed with the H Bars (one or two piece) they will have 1070 mm centres. Sheets are available from 1.5 m to 9.0 m long.

Sheets are joined using an Aluminium H Bar – these can be one or two piece.  Under normal conditions all of the screws that hold the system down will go through the H bar.

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

Aluminium Edge Bars are very similar to H Bars – but they have one side of the H closed off.  They are used on the sides of the structure to make the unused edge look tidy.

Sealing tape –  applied to the bottom (gutter) end of the sheet to cover the open ‘flutes’.

Breathing tape – is applied to the top end of the sheet to cover the open ‘flutes’.

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

Find the Laserlite Multiwall Installation guide here.

Answers to the most common questions:

  1. The sheets are UV2 – they have UV protection on BOTH sides, this means it does not matter which way up the sheet goes.
  2. There are 2 DIFFERENT gaskets.  One for the end cap and one for H Bars.  It will make it very hard to put the system together if you have them mixed up.
  3. Sheets should run with the open flutes running WITH the fall.
  4. If you have trouble getting the the sheets and gasket into the aluminium bars (firstly refer to point 2), you can spray a little soapy water onto the gasket to reduce friction during installation.


Once the roofing has been installed you may choose to add flashing to assist with water proofing. See below images for the main types of flashing that you may need to consider.  All of these are provided by others (we don’t sell them).

Have any questions or need a quote?
or call us 1800 506 454

31 thoughts on “Laserlite Multiwall Installation Guide with Tips

  1. Hi im just about to install clear polycarbonate roofing to my pitched roof pergola, wondering how i fit the roof capping if i cant stand on the poly materials ?

    1. Hi Paul
      Thanks for your enquiry. It is most important you do not stand directly on any polycarbonate sheeting. Use a crawl board (plank) which should extend across 3 rafters to spread your weight across the sheet. You may also want to put something under the crawl board so that it does not scratch the sheet.
      Regards Team PCR

  2. The aluminium H bar used to connect two 10mm twinwall polycarbonate sheets together. What type of screws do you recommend to use to attach the H bar to treated pine timber rafters to avoid electrolysis with the aluminium. Also the size of the screws?Cheers Ray

    1. Hi Ray
      Thanks for your enquiry.
      For screwing into timber you would need a 12g x 50mm screw for the 1 piece H Bar, zinc plated so electrolysis won’t be a problem.
      Regards Team PCR

    1. Hi Leonard
      Unfortunately no we don’t have any videos for the Laserlite Multiwall installation.
      There is a (printed) installation guide on the website and I will email you this and a step-by-step guide as well that may help.
      Regards Team PCR

  3. Hi
    Just confirming, is the breathing tape applied to to low gutter end of the sheet and the blocking tape to the high top end as in your instructions?
    installation guides for other brands say that the the opposite- ie breather at low gutter end and blocking at top high end.

    1. Hi Simon
      Thanks for your enquiry.
      No, the breather tape is applied to the top/high end of the sheets and the block/sealer tape is applied to the bottom/lower end of the sheets as per the installation instructions.
      Regards Team PCR

    1. Hi Michael

      It may depend if you have one piece or 2 piece H bars. One piece H Bars would make this almost impossible (sorry) without disassembly and reassembly… 2 piece will require taking off/loosening top section before carefully pushing sheet back up. Remember safety first – to access the roof. Generally, crawl boards are needed.

      This would indicate that the end cap has either not been used, or installed incorrectly – it should be firmly attached to the H bar and Edge bar at every junction – this will stop this from happening.

      Trust this will help.
      Team PC

  4. Hi, are the multiwall sheets sliding directly in the edge bar, or do you need the H profile at the first rafter, which is then blocked off with the edge bar?

  5. I am using Laserlite 10mm multi wall for a awning over the entrance door. I want to have a 50mm over hang over the bottom roof batten and need to know how to integrate the ‘H’ bar and its gasket with ‘end cap’ and its gasket.

    1. Hi Terry
      You will need to cut the end cap GASKET to fit in-between the H Bars and then fit end cap onto the end of the sheet/gasket. The end cap then fits OVER the H Bar so you then rivet the end cap onto the H Bar. Then drill a small weep hole on the underside of the end cap where it meets the H Bar.
      Link for Installation instructions below:

      Regards Team PCR

  6. Hi,
    Q1: The installation instructions describe how to use the Aluminium End Cap on the bottom sealed end of the sheet. How is the top end of the sheet fixed to a wall to allow the Breather Tape to breath?

    Q2: I have a height problem and wish to use a 2 degree slope. Is this possible?

    1. Hi Peter

      A1. The system is usually NOT fixed to the wall – an apron flashing would be recommended to seal. End cap is used on BOTH ends.
      A2. No, 2 degrees is NOT recommended. You may have trouble with water pooling, leaking and dirt mold inside the sheets.

      Let us know if there is anything else we can help with
      Team PC

    1. Hi Glenn
      Thanks for your enquiry. Laserlite products are not made in Australia, they are manufacturer in Indonesia.
      Regards Team PCR

  7. Hi
    Q1.can the top end cap be in long lengths like the bottom end cap and does it get screwed to the h bar as well and are the h bar cut to the exact same length as the multiwall sheet

    1. Hi Riccardo

      Thanks for your enquiry.

      The Laserlite aluminium end cap comes in lengths of 6.5m so yes you can install this in one continuous length. If you have more than 6.5m then the join should be at a junction with the H Bar.
      The end cap will be riveted to the H Bar. The rubber gasket that fits inside the end cap would need to be cut into sections to fit in-between the H Bars on each sheet.
      Fasten the Aluminium End Cap with a screw to the H-Bar. On the underneath of the Aluminium End Cap drill a small weep hole where it meets the H-Bar.

      Regards Team PCR

  8. I’m filling in the the edge of the patio roof to the fence line then vertically down to the top of the fence with multiwall.
    Can I join all the sheets with H bar but only? Then screw them at the top of the sheet and the gutter end of the sheet? The maximum distance in the length is 1400mm. I have no rafters.
    The same with the vertical section with a drop length of 750mm.
    Thanks Sonya

    1. Hi Sonya

      Thanks for your enquiry.
      Under the manufacturers installation guide, you must have rafters underneath the H Bars to screw down onto. So no, you cannot span the Bars
      from top to bottom.

      Regards Team PCR

  9. I am having trouble forcing the end cap over the gasket. I have tried a soapy solution (windex) and still have problems. Is there a better lubricant?
    Thanks Peter

    1. Hi Peter

      Do check that you have the correct Gasket (sorry we have to ask!). Also make sure that the gasket is cut to individual pieces and applied to the sheet only (not over the HBAR).

      Assuming that you are going that, it usually is a snug fit. I can not comment specifically on windex, we would usually recommend a standard dishwashing liquid as your best bet.

      If you have further problems, get in contact and we can try to assist further.

      Team PC

  10. I have had 10mm twinwall Lsaerlite installed recently and the gasket at the underside of “H” section keeps coming out. Is this an installation problem? The installers just trim it with a knife

    1. Hi Peter

      If it is the Laserlite Multiwall – the gasket should be a C section. Yes, i would be concerned if it was ‘coming out’ and being trimmed. Probably not fitted correctly when installed. It should sit neatly top and bottom.

      Team PC

  11. we have 15m long sloped roof that we would like too cover.. I can not say I looked everywhere but quite long time with no result.. Panels come up to 9m long.. how do I connect them on the length..

    1. Hi Thomasz

      It really depends on the type of panels that you are looking at.

      Most profiled sheets (e.g. Corrugated, greca, trimdek) simply overlap. If your are looking at other styles of sheet then they will usually require a step in the roof so that one is lower than the other.

      Give us a call to discuss what might be appropriate.

      TEAM PCR

    1. Hi Rick

      Generally circular saws (most manufacturers recommend a fine tooth blade), otherwise a jigsaw also works.

      Team PCR

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