Which Thickness of Rubber Roofing Membrane Should I Buy? (1.2 mm or 1.5 mm)

You might be wondering which thickness of ClassicBond EPDM will be most suitable for your replacement rubber roof project. It’s a good question that we get asked a lot. As always, it depends on the specifics of the job. Watch our short video to help you decide which is best for your project.

Video Transcript

Another short video today – we’re going to be talking about the differences and the
similarities between our 1.2 standard membrane and the 1.5 premium.

So we get asked this on a daily basis; what thickness does my EPDM membrane need to
be? Hopefully, this video will answer these questions.

So first of all, both membranes are perfect for your residential and your commercial flat
roofing and standard roofs, like your garden rooms, extensions, dormer roofs, things like that.

So they’re both installed exactly the same way – the 1.2 and the 1.5 and your water-based adhesive on your main deck is standard, and your contact adhesive around your perimeter.

So if nothing’s going to be installed on the EPDM after it’s been installed then we would normally just recommend the 1.2 membrane . This works out a little bit more cost-effective for our customers.

We will however recommend the 1.5 membrane if a particular product is going to be going on top of it after it’s been installed. So this could be decking, ballast, screeding before you put tiles on or green roofs.

Some of the contractors that buy from us do use the 1.5 mm on all their work, they do feel that it does lay a little bit better with that added thickness it also covers up lumps and bumps a little bit better as well. Having said that, lumps and bumps shouldn’t really be an issue as both of the membranes are designed to be laid onto new decking boards.

Just to touch on the weight of the membranes as well, the 1.2 weighs just over 1.5 kilo per square meter and the 1.5 weighs just over 2, so a typical 20 square meter roof will weigh 30 kilo for if you’re using the 1.2 membrane and 40 kilo if you’re using the 1.5, so just bear that in mind when you have got larger roofs to do, you might want to split them down because of the weight.

So just to finish, they’re both BBA certified and they’re both fire rated the 1.2 has an AB fire rating and the 1.5 is an AA.

Ready To Order?


Order your EPDM flat roofing system by selecting the required length and adding to the basket, or simply give us a call on 024 7666 7234 .

ClassicBond 1.2 mm

ClassicBond 1.5 mm

Water Based Deck Adhesive

For further information on our EPDM Rubber Roofs, take a look at our FAQ’s

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