leaking fibre glass flat roof

28 Nov 2010
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West Glamorgan
United Kingdom

I have recently fibre glassed a flat roof on a new dormer loft conversion I am building and i have just notice today that the sterling boards are extremely wet in places! I have no previous experience with fibre glass but i felt with a bit of research it was possible to do it myself(maybe not eh!). I carried the work out when it was dry and I used 1 layer of fibre glass matt which i soaked thoroughly in resin, when the resin was slightly still sticky but not quite set I then poured and rolled out the top coat. It looks and feels great from above but is obvioulsy leaking in places. Any ideas much appreciated. Thanks
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is it the underside of the boards is wet? If so, could it be condensation?
Thanks for your replies. I did wonder if it was condensation but the joists are well ventilated and the borads were really wet from underneath but it did sem to be concentrated on the left and right sides.....I wonder if it is anything to do with the moulded raised edges and mabybe it is tracking along them somehow. I am thinking about giving it another thick top coat to see if that does anything.
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How does the water drain from the roof and is there a drip edge designed into your fibreglass roof. There are lots of ways water will ingress and usually they are caused by poor design. Without looking at what you have done it will be difficult to comment on how to solve your problem. Any chance of some pictures??
yes, can get some pics. I have got a proper moulded raised edge on either side and a proper moulded drip into the gutter at the front. Admitadly i did not have enough of any of the moulded pieces and in a panic I ploughed on regardless hoping i could mould some fibre glass to continue these pieces on and not have gaps. It kind of worked cos i shaped some lead to follow the shape of the moulded edges and fibre glassed over the lead. It looks ok but could this be my problem? At the very back of the roof I have ridge tiles bedded in mortar sitting over a continuous strip of 11" lead that is shaped over a batton of 2 x 1. This area is bone dry inside. My problem areas are the sides for some reason.
put some pics in my images for you to see. its been raining here now for 36 hours and no sign of water through the roof. Really confused , think it maybe condensation cos since i took down celotex from between joist there has not been so much as a drip of water. What is weird though is there is plenty of ventilation cos I have a 2m x 1m hole where the window is going and no soffits yet?

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