re roofing with fibreglass and resin

[news]

I wonder if anyone has experience of placing fibreglass over an existing flat roof?

I have a building which is simply a flat roof fixed between rendered brick walls. The problem is the steel profile sheeting was laid too flat and the gutters of the adjacent roofs overflow, the subsequent deluge overwhelms the flat roof and water gets in via the overlaps. I have painted these with resin sealant but this hasn't survived the movement of the panels over time, I also think some water is getting past blown render.

I am considering just tanking the roof and up stands with fibreglass but wonder if this should be applied directly or a membrane used to allow for differential movement?

AJH

[Tim Lamb]

In message , [e-mail] writes

I use butyl sealing strips under the laps and then stitching screws at

18" intervals. OK for rain splash but not guaranteed for immersion.

Can you not sort out the gutter issue?

I think there are roofers specialising in glass fibre work but I have no direct experience.

[Peter Parry]

About 5 years ago I helped a friend replace a leaking felt roof on a flat roofed garage and kitchen extension with fibreglass laid directly onto the boarding underneath the felt we stripped off. One side was the house wall and we used a fillet trim similar to

to make a neat join to the wall. No problems at all with it since.

[Andrew Mawson]

I have two experiences of fiberglassing roofs:

First experience entirely positive, I formed a box valley between the house and a garage I'd built. Made the channel shape in exterior ply, and laid two (or may be three?) layers of resin and fibre matting - worked superbly

Second experience partly positive. I had a leaking PortaKabin roof - galvanised overlapping flat sheets. The plan was to sheath it in fiberglass so I bought a kit and went at it. Day was overcast, sheets were cool. I measured their temperature and mixed the resin accordingly. Started off fine, went down well, until the clouds cleared, the sun beat down and the sheets got very hot very quickly. The resin set before I could flatten it down properly and it looks a right mess (luckily it's not visible unless you climb up there!) however it cured the leaks and we've had no rain in for two or three years now :)

Andrew

[news]

I had used a fibre reinforces acryl paint

The problem was exacerbated by a build up of leaves effectively damming the furrow of the profile sheet, so after a recent deluge the gutters overflowed from the two adjacent roofs and the flat roof probably had 50mm of standing water on it, water that did flow off the lower edge overfilled the gutter, which was half filled with debris and seeped back into the void between the joists and ran back between the roof sheets and ceiling.

The infill was amazingly poorly though out but it currently provides

60m2 of storage and I cannot find a home for the bits and pieces in order to start again.

I need a solution which doesn't require more than annual cleaning. I will fit deeper gutters and drop them by a couple of inches.

AJH

[news]

Looks don't matter, no one can see it. So the thermal expansion of the steel wasn't a problem? It looks more promising, espaecially as one of the guy's father is a GRP boat builder.

AJH

[news]

Yes I've seen decks sheathed in fibreglass so I know it's ok with wood, I was a bit concerned about laying it direct onto steel.

I think I'd lay it right up the walls to the eaves as looks don't matter.

AJH