Green Building Forum - Flat Roofing Options Resitrix, EPDM, PVC? Sun, 19 Apr 2026 03:30:09 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 Flat Roofing Options Resitrix, EPDM, PVC? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=283068#Comment_283068 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=283068#Comment_283068 Wed, 02 Sep 2020 14:05:41 +0100 nickbartleet
I've been going around in circles looking at flat roofing options, from economical EPDM £6k to Single Ply PVC £22k, and struggling to make a decision as i know it is an important one. I am concerned with EPDM not lasting due to the glued seams and shrinkage which seems to be the most common complaints. I found a product that a local installer uses called Resitrix, which seems to eliminate my EPDM concerns as it is heat weldable and much thicker than other membranes at 3.2mm. I was hoping to get some insight from people who have installed flat roofs and thoughts on different products.

Here is a link to resitrix (any info from people who have used it would be really helpful).

https://www.resitrix.com]]> Flat Roofing Options Resitrix, EPDM, PVC? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=283080#Comment_283080 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=283080#Comment_283080 Wed, 02 Sep 2020 19:47:20 +0100 djh Flat Roofing Options Resitrix, EPDM, PVC? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284866#Comment_284866 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284866#Comment_284866 Tue, 24 Nov 2020 09:21:21 +0000 lineweight
Some questions

- Does one of PVC or EPDM have a clear environmental advantage?

- Again from an environmental point of view, what about fibreglass - worse or better than membrane type systems?

- Small-scale builders nearly always want to do fibreglass or built-up felt on flat roofs, instead of membranes. This is usually because they can do it themselves instead of getting in a subcontractor. It usually seems to be a cheaper option on small jobs because of this. In terms of longevity, do felt or fibreglass really perform that badly?

- Are manufacturer-backed warranties (sometimes offered by membrane system suppliers) worth the paper they are written on?]]> Flat Roofing Options Resitrix, EPDM, PVC? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284867#Comment_284867 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284867#Comment_284867 Tue, 24 Nov 2020 10:10:54 +0000 Peter_in_Hungary
What about standing seam tin. (tin = galvanized steel sheet)

Over here torched on bitumen is often used, it comes in rolls and is 4mm thick]]> Flat Roofing Options Resitrix, EPDM, PVC? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284868#Comment_284868 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284868#Comment_284868 Tue, 24 Nov 2020 11:00:15 +0000 owlman Flat Roofing Options Resitrix, EPDM, PVC? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284871#Comment_284871 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284871#Comment_284871 Tue, 24 Nov 2020 19:50:38 +0000 LF Supplier came back and sorted mainly warranty , but they helped by doing some other work.
I would say it was not really their fault, is was poor ventilation to get rid of moisture build up.

EPDM not especially thick but no leaks and a fair few seams. OSB was used for underneath layer this time.
More ventilation added etc. Insulation is under the wood layer, no vapour barrier.

This replaced a 20 odd year old fibre glass roof.

A decent warranty would seem to be worth having.]]> Flat Roofing Options Resitrix, EPDM, PVC? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284877#Comment_284877 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284877#Comment_284877 Wed, 25 Nov 2020 09:50:50 +0000 Jeff B
Admittedly I have no experience of EDPM or PVC but I would recommend fibreglass, not least because you can walk on it without any fear of puncturing the surface! Not sure if that is the case with the other materials?

Edit: just had a look at the Resitrix videos. Looks good stuff, would be interesting to see examples of actual applications.]]> Flat Roofing Options Resitrix, EPDM, PVC? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284931#Comment_284931 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284931#Comment_284931 Sat, 28 Nov 2020 20:16:56 +0000 jms452 Posted By: lineweight- Does one of PVC or EPDM have a clear environmental advantage?

Plastics with Chlorine in have nasty decomposition products and are not currently widely recycled.]]> Flat Roofing Options Resitrix, EPDM, PVC? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284932#Comment_284932 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284932#Comment_284932 Sat, 28 Nov 2020 20:32:19 +0000 djh Posted By: jms452
Posted By: lineweight- Does one of PVC or EPDM have a clear environmental advantage?

Plastics with Chlorine in have nasty decomposition products and are not currently widely recycled.
and just to be clear - the C in PVC stands for chlorine and there's no C in EPDM.]]> Flat Roofing Options Resitrix, EPDM, PVC? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284939#Comment_284939 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284939#Comment_284939 Sun, 29 Nov 2020 13:24:25 +0000 jamesingram PVC usually get a bad press,
Greespec as ever lays it out neatly
https://www.greenspec.co.uk/building-design/flat-roof-coverings/

I use fibre glass if there's any sort of fiddly detailing and EPMD for anything that's straight forward and not likely to be walked on. These are for just small domestic work'
I know a contractor that fits Restrix commercial and raves about it. I'm tempted to get him on my next project that suits it.

Best roofing solution
1.reclaimed tiles or slates
2. wooden shingles certified source
3. natural slates (local)
4. clay/cement tiles (local)
for flat roof see greenspec above]]> Flat Roofing Options Resitrix, EPDM, PVC? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284953#Comment_284953 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284953#Comment_284953 Sun, 29 Nov 2020 19:45:44 +0000 lineweight Posted By: jamesingram
Greespec as ever lays it out neatly

The problem I have with greenspec is that it never really gives you an objective answer (perhaps because that's impossible).

For example, if I compare PVC with EPDM,

- EPDM has 3 positives and 4 negatives listed
- PVC has 3 positives and just one negative.

One reading of that might be that EPDM is more problematic, but I don't think we are supposed to consider the pros and cons listed each to be equally weighted. It's mentioned for PVC that for "many designers" it's rendered "unacceptable". But this information isn't really very useful - what am I supposed to do with it?

Of course, I could spend a day, or a week, reading up on PVC and all the arguments pro and against, and come to my own conclusion. But the fact is that no specifier or designer can do that for every single product and material they come across. Even if they were technically competent to do so and make a good judgement, there's not the time to do that and also actually design or build anything.

I don't know what the solution is. But looking at Greenspec often doesn't leave me feeling any more confident about making the best decision.]]> Flat Roofing Options Resitrix, EPDM, PVC? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284954#Comment_284954 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284954#Comment_284954 Sun, 29 Nov 2020 20:00:37 +0000 djh Posted By: lineweightlooking at Greenspec often doesn't leave me feeling any more confident about making the best decision
I agree but TBF I don't think the problem is specific to Greenspec. In any complex decision it is quite normal that there's no 'best' way to balance the various factors against one another. Every person or organization has to make their own judgment. All that others can do is point out the various factors and illustrate what their relative importance might be.

Price is probably the most controversial factor. It's a primary factor for most people and a strong influence in the prevalance of UPVC windows, for example. Yet some organizations, such as Which, think they're doing us all a favour by ignoring price as a factor.

For myself, I read up enough to convince myself that PVC is a bad choice where there are alternatives. YMMV.]]> Flat Roofing Options Resitrix, EPDM, PVC? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284966#Comment_284966 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284966#Comment_284966 Mon, 30 Nov 2020 10:40:36 +0000 lineweight
That's not to say it isn't useful.]]> Flat Roofing Options Resitrix, EPDM, PVC? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284969#Comment_284969 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=284969#Comment_284969 Mon, 30 Nov 2020 11:40:49 +0000 jamesingram
Yes the pro and cons need to be weighted differently. Personally I feel informed broadly enough generally to do this.]]> Flat Roofing Options Resitrix, EPDM, PVC? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=285018#Comment_285018 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=285018#Comment_285018 Tue, 01 Dec 2020 23:03:50 +0000 Mike1
I've a (very) small tower roof to do next year, and for that I'm currently inclined to go for mastic asphalt, if the cost is reasonable, with an inverted design (insulation + tiles on top).]]> Flat Roofing Options Resitrix, EPDM, PVC? https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=285020#Comment_285020 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16699&Focus=285020#Comment_285020 Tue, 01 Dec 2020 23:08:18 +0000 lineweight Posted By: Mike1Whatever the material, the installation seems to be the key.

This is why anything with a meaningful warranty is so attractive.]]>