GRP roof delamination

[Taffbats]

Hi guys

I fibre glassed my single story kitchen extension a few years ago, its is still water tight but I have noticed that slowly it is bubbling up in places and starting to delaminate, and the top coat is already looking faded and the yellow underneath is starting to show, my worry is I don't know if this will stay in one area or if it all will fail in time....so, because I don't want to rip it up and start again ..can I board over with 9mm osb board because I want to keep the weight down and then glass?
I'm also looking at other options like felting or rubber roofing over?
I was also thinking about screwing down the delaminated areas to prevent from moving and then using something like liquid rubber roofing and scrim over? but I've heard somewhere that grp roofs give off a vapour or something and prevent stuff sticking to it?

What do you think are my best options?

Thanks
Kev

 

[HERTS P&D]

Sand down the whole roof and recoat then apply a top coat.

Andy

 

[Taffbats]

Thanks Andy but what about the delamination?

 

[HERTS P&D]

Well if you sand back the delaintion areas then reapply fibre class then top coat.

The good thing is that it is still water tight, so you can wait until good weather.

Post some pictures.

Andy

 

[Taffbats]

When you say sand it back do you mean literally just sand it? Or do I cut out the delaminated area first and then patch?

 

[HERTS P&D]

I would sand it back to where it has not delaminated. Then re-fibre glass.

Andy

 

[oldbutnotdead]

As above, you need to sand the topcoat off, grind out the delaminated bit(s), patch the glass then topcoat.
When you grind the failed bits out you may find that the osb has gone soggy, usual fail here is pinholes in the topcoat allowing moisture into the glass which is a bit porous, freeze/thaw will do the rest of the damage.