GRP roof - best time for work - and is it any good?

[KateMoss]

I recently made some enquiries about replacing my felt flat-roof with GRP. One roofer told me that he could fit GRP but it shouldn't be done in January as it needs a few dry days to complete the job, he was also a quite sceptical about how good GRP was anyway and said that he had heard of 'lots of problems' with it; his favoured material was torch-on felt.
Another roofer said GRP was the best material and he could do it as soon as he got one dry day (in January).
I was originally very keen on GRP but am now beginning to have doubts.
Could anyone comment on the above please?
Thanks.

 

[cotswoldbuilders]

Torch on is better than grp, so is epdm.

 

[oldbutnotdead]

I'm just doing a GRP valley (its a wide valley- 2m ish x 10 metres) to replace the failed lead. Trying to do it this time of the year is iffy- you need a dry (ideally sunny) day to put the resin down and (depending on how big an area you're covering) you need a dry day to put the boards down (resin won't bond to damp boards)

You do need a solid deck. GRP is good stuff but if you flex it often enough across an edge then it will crack (my main experience with the stuff is motorcycle fairings but the chemicals are the same). Long term I can't tell you how well mine has worked but so far the valley has been absolutely watertight since I did the resin. Just need a dry sunny day to get the topcoat on...

If yours is an easy flat roof (as in no awkward up and down slopes, sticky out bits etc) then EPDM is probably a better bet. I prefer to avoid hot work wherever possible- keeps the risk assessments managable!

 

[Xenon]

Another roofer said GRP was the best material and he could do it as soon as he got one dry day (in January).
.

He's not a roofer.

 

[KateMoss]

Thanks for the useful replies, I am edging towards torch-on felt as it seems to have least number of serious negatives according to my research. One more option has cropped up though - bonded Alwitra Evalon-V single ply membrane. I can only find sales promotion material which of course is very positive and would be very grateful for any comments on this solution if anyone has experience of it. Thanks.