GPR roof

[thuynh7]

I had a GPR roof installed on a wooden cabin a few years ago by a builder that insisted on doing it rather than a felt roof. He's since gone bust but I've paid to get it repaired twice now by two parties and still it leaks, it's costing a lot of money and the internal ceiling is all moldy and totally destroyed. Realistically what's my cheapest option, also can you felt over a GPR roof? The cabin is only 4m x 5m

 

[oldbutnotdead]

Is the GRP definitely leaking? The internal ceiling going mouldy and rotten smacks more of condensation/ventilation issues. Is the roof warm deck or cold deck? Is there any ventilation at the eaves?

Is this a flattish roof or some sort of complex shape?- reason for question, as long as the roof deck was properly installed (to be rigid) then GRP is dead easy to install and to repair. Clue- if you stand on the roof it should either not deform at all or it should deform as a single unit (unless it is a large cabin and there are expansion joints in it). Mimimum thickness of deck for GRP is 18mm OSB- if your deck is thinner than that then GRP isn't going to work.

And felting over it- I'm not sure how well torched felt would bond to GRP- my suspicion is not very well so you'd probably want to stick some 8mm OSB or similar down first. Or you could look at EPDM

 

[thuynh7]

It's just a flat roof, I think the OSB was quite thin, hence all the problems I'm getting. The internal ceiling leaks quite a lot when it rains. I think I will give EPDM a look.

regards