Best Vapour Barrier for Flat Roofs

Best Vapour Barrier for Flat Roofs

This video shows me testing the vapour barrier when we did a job late last year. A primer for the vapour barrier is recommended if you are going to glue down over the top of a surface that not sound and should also be used if its cold. It sticks very well sometimes too well if you let it touch itself you have to throw it away as you just won’t get it apart.

There are four suppliers that I know off that will supply this self-adhesive best vapour barrier for flat roofs.

Only one of them will supply by the meter, and that is:

If you use our promo code LFR2013, you will get our discount  (if the promo code is not working phone and mention this site and get the new one)

Why is it the Best Vapour Barrier for Flat Roofs?

  • Vapour resistance of 2000 MNs/g.
  • Self-healing if punctured by fixings.
  • Temporarily waterproofs the roof ( can stay uncovered for up to 3 months).
  • Self-adhesive.
  • Easy to install.

Its not cheap, purchasing it by the role and by the pallet load is cheaper but is a considerable layout.

Overlapping Joints

If you are going to order this for a flat roof and your roof is say 20m² make sure you order closer to 28m² because of overlapping joints, you don’t wont to run out.

Another good thing about this vapour barrier is that it bridges small gaps, it’s designed to bridge over the corrugations on metal roofing sheets and not to break even if you step on it. The corrugations can be as wide as  150mm in some cases.

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Comments (4)

  • James Reply

    Thanks for the useful information regarding flat roofing.
    Would you recommend an expansion gap when fitting the OSB boards to a newly constructed warm roof?

    16th October 2018 at 9:56 pm
  • JOHN BAKER Reply

    which vapour barrier for warm flat roof

    29th May 2020 at 6:35 am
  • Paul Shacklady Reply

    Hi Steve, really like all your videos really good and informative. I’m just contacting you for some advice we have a flat roof I believe it’s a cold roof it’s a GDPR system. I believe it is we are looking eventually to replace this in the next few years however, the problem being is that I’ve got cladding as the ceiling and we’ve got a floor to ceiling wardrobes fitted so I can’t change the ceiling type. We have had leakage believe this to be condensation which has come through and driped through the cladding and along down the walls. I’m just looking for a solution to hopefully last a few years before we can afford to replace this roof altogether and we will probably look to replace it using the rubber system. Is it EPDM system? so we’re just looking for advice. What should l do? is there anything I can do now to to get this all sealed and prevent condensation. As you can see from the photos. Any advice would be much appreciated. Cheers thanks Paul
    Photos attached:
    Internal photos
    External photos

    19th February 2023 at 4:40 pm
    • Steven Dickinson Reply

      sorry for the late reply I get so much spam on this that is really hard to find the real people who need help. However I’m here now if you need help still please just email email me speak soon

      19th August 2023 at 8:57 pm

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