[Eichhörnchen]

It's a shame that Antze has left us as he'd surely know the answer to this.

The guys who put up my in-laws' 8X6' garden shed covered the roof with fibreglass. Now I've never seen this before; it's a continuous sheet of thin fibreglass (maybe 2mm) over a gently sloping flat timber roof, but they haven't created an overhang after wrapping it over the edges of the roof. If I'd covered this roof with felt, I'd have left an overhang of a couple of inches all round to shed the water. They've instead just cut the fibreglass level with the lower edge of the timber roof's frame.

Anyway, there are no cracks in this roof but it's leaking inside, and I think that maybe water is getting sucked in along this outer edge by capillary action (Moira's father was a fish farmer, used to building all kinds of systems to handle and contain water, and his favourite saying was "Water will always find a way").

My question is: if I run a sealant all round to seal the edge of the fibregass to the timber, what would be the best sealant to use? I don't want one that's going to be incompatible with the fibreglass, that's the main thing.