Glass Fibre roof curl.

Last summer I asked here about a 20 x 4 foot glass fibre roof on my son's house. Well, we went ahead and did it, laying OSB board and then getting one layer of glass and resin on as the rains came. This layer had some pinholes and when it set we could see water underneath the resin and puddles on top.

We dried this as best we could and on a dry day we did another layer of resin, and some days later a layer of surface tissue and resin. The weather was terrible, so the work was done at random times when he was there and the weather allowed. At the edges he used simple right angle edging rather than the type that forms a sort of small raised edge.

The ceiling beneath the old felt roof had been damaged by the water coming through that roof, so he removed parts of this and heated and ventilated the area to help dry out any remaining damp in the new roof. The area is basically a corridor and storeroom and has since been closed off through the winter.

The roof is now waterproof but he is now saying that, at the two free corners, the fibreglass is starting to take a gentle curl upwards.

As far as I know, he left expansion gaps between the OSB boards. I think it may be that the boards never have dried out fully, but he thinks it may be some problem with the conditions the fibreglass was laid in and the lack of the raised edging. He is now talking of treating the whole operation as a training exercise, ripping the whole roof off and starting again.

I wonder if anyone else has experience of fibreglass bowing upwards at the corners after being laid. Or of this OSB2 with a black weatherproof coating expanding through damp?

Reply to
Bill
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I don't know but my feeling is that the bond between the layers is not good due to damp and time between them. Is it delaminating or detaching from the OSB as a complete multi-layer curl?

The spec for the boards on our new glassfibre roof last year was for 22mm OSB3, no black waterproof coating. I wonder if that has reacted with the resin? Or if it has stopped the water that did get behind the first layer making it's way through the OSB and disipating.

It wasn't exactly dry here when ours was done, first layer one day, swept the water off and then a BFO burner to dry and warm it for the second coat the next day.

Reply to
Dave Liquorice

In my experience, fibreglass resin will not adhere to bitumen.

Reply to
Mr Fuxit

I've had a look from ground level (no access to a ladder there and he is away for a couple of weeks) and the lift is quite significant at one end. The OSB3 board we used was called Metsa Wood Roofdeck, and we took off the cellophane-like covering before we fitted it. The black on one face and sides looked like a sort of thin matt paint, and was a surprise to us at the time.

The job was rushed, delayed, rushed because of the weather, so I'm going to suggest we take a "core sample" through the bad part to see what we find.

Thanks, Dave and Steve. I'll try to report back with what we find, but it may be a few weeks.

Reply to
Bill

So many ways this could go wrong

Did you use a resin system intended for roofing?

Did you follow their application guide *to the letter* ?

Reply to
The Other Mike

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