Fibreglass roof leak!

Block99 · 20 Feb 2020

Hi.
I have a fibreglass flat roof that is only about 8 years old. We have recently noticed the corner of my bedroom is damp. I've been up on the roof and it looks like the external corner isn't sealed. But I'm not an expert!!!

Can anyone look at this photo and tell me if it looks right??

Thanks

johnny2007 · 20 Feb 2020

Not a roofer, but surely that corner is letting water in.
Looks like they used a heavy hand of topcoat instead of fiberglass AND then topcoat.

Block99 · 20 Feb 2020

So could I just seal that gap up with something?

bobasd · 20 Feb 2020

its wrong - the edge trim and the field are wrongly applied.
any possible original corner trim piece seems to have broken away.

see "fixmyroof.com" youtube videos on how to do the job properly and there's sure to be other vids about repairs.

or you can use flash band to give a temp repair. do that immediately and then think about your next move - but you must stop water entering your roof.

your long term problem is that that roof was wrongly installed and is now beginning to fail - starting with the edge
trims lifting off.

Rufus Raintight · 21 Feb 2020

Is it possible to upload a side-on view and another corner of the roof for comparison? Do you have a guarantee for the roof?

Depending on how they've been trained fibreglass roofers will more than likely not use pre-formed corners instead they will make them on-site with resin and glass and then topcoat over it once cured, which is cheaper for them. That corner can't have been like that for 8 years or you would have had seen problems before now, has something come away from the roof?

It can be fixed by abraiding the surface and applying more resin, glass and topcoat, but as said above a temporary repair needs to be done ASAP, get a few quotes in from roofers who can actually see the roof and are going to be able to assess it better.

Vinty · 21 Feb 2020

Good advice above.
I did a contractors course with this company many years ago.
https://polyroof.co.uk/contact-us/
They manufacture preformed edge and corner trim for GRP roofs.
Contact them and maybe they can advise and supply you with what you need.
The only problem i can see is that if damp has got under the glass deck it could cause a problem.
Polyroof used to have their own approved contractors list although i don't know if that is still the case.
The advantage of using their approved contractors was that you got a genuine guarantee if anything went wrong.

FrodoOne · 21 Feb 2020

Block99 said:
So could I just seal that gap up with something?

If that is where the water is getting in - YES.

Since you have taken those photographs it seems that you have relatively easy access to the problem area.

I have no idea as to how that roof was constructed but, if it is fiberglass and when dry, the obvious thing to do is to place a piece of fiberglass mat underneath the existing surface material (with some material underneath that, to stop any adhesion to the substrate) and mix an appropriate amount of two-part epoxy resin to soak into the fiberglass and the existing material, to make a watertight layer and join.
(Some epoxy resin materials may require painting to avoid deterioration due to ultra violet light.)

If you do not wish to do that (because of the trivial cost of a quantity of two-part epoxy resin or some such objection), you could use some waterproof material underneath the existing surfaces and seal with a silicone sealant.
That would last as long as the life of the waterproof material concerned and/or the silicone sealant.

Good luck.

Rufus Raintight · 21 Feb 2020

FrodoOne said:
I have no idea as to how that roof was constructed but, if it is fiberglass and when dry, the obvious thing to do is to place a piece of fiberglass mat underneath the existing surface material (with some material underneath that, to stop any adhesion to the substrate) and mix an appropriate amount of two-part epoxy resin to soak into the fiberglass and the existing material, to make a watertight layer and join.
(Some epoxy resin materials may require painting to avoid deterioration due to ultraviolet light.)

Epoxy?

That would be total overkill for something like this and you would still need to purchase the topcoat to match the existing finish. You can get a GRP roof repair kit that includes the glass, polyester resin, catalyst and topcoat (to match the roof) for under £50.

oldbutnotdead · 21 Feb 2020

Is there another corner on your roof that hasn't failed- be interesting to see how that one was finished.
Best bet atm (as others) is do a temporary repair with flashband/acrypol, try and leave an airgap under the repair so any trapped water can evaporate out.
When doing grp rooves like that i've always mitred the trims then mat, resin, topcoat- the manufactured corner trims are fine if your corner is true 90 or 45 degree but less useful in the real world.

catlad · 21 Feb 2020

Acropol is a perfect diy solution for that job with some fibreglass bandage.

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Fibreglass roof leak!

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