Fibre Glass Roof Leaking from an Edge

[Sajid Patel]

Hi

I would be grateful if someone could advise me of a solution to seal the edges of my roof to prevent water seeping in through the edges.

I have a Fibre Glass roof over my loft all over except for the part that slopes down. The party walls are raised on both sides by some 6” above the Fibre Glass roof with beading installed to terminate the roof under the beading. The top of the party wall is finished with coping stones and sloping part of the roof has lead at the edges where the roof terminates with the wall.

The issue I have is water is seeping at the edge of the roof and on to the walls and ceiling inside. See attached picture with red dotted lines in which you can see water marks on the ceiling and the area of the leak. I have included another picture with the roof area directly above this. It’s the picture with yellow dotted lines and measure tape.

It appears to me that water on the flat roof is running towards the back of the roof and possibly getting through under the lead (where lead meets the roof). However, internally the water mark damage is showing to be starting from at least 3 feet before the sloping part of the roof. It is then possible that water is also seeping through the small gaps between the roof where it terminates and the party wall? These gaps have got silicone in it but it appears it has not stuck well in places where it was previously bonding to fibre glass.see attached picture with arrows marked blue and purple.

what is my best cost effective solution to seal the edges all around and to seal the part of the roof that meets lead? I don’t want to go through huge expense of installing lead at this point in time.

thanks and look forward to some advice

 

[catlad]

Firstly slates need soakers and why haven't you gone over the wall with the grp?

 

[Sajid Patel]

Hi Catlad

This was all done as part of the loft build by the builders 6 years ago. I wouldn’t know about soakers or why they didn’t go over the wall. At the time I had zero know how GRP so I guess they did what they did and got away with it. Can’t get hold of them now which is typical of some builders.
Thanks

 

[HERTS P&D]

Did you hire Cowboys or Indians?

Andy

 

[Sajid Patel]

Neither Andy - Overall the work is satisfactory and to high standards so I won’t write em off completely but they sure got it slightly wrong with the roof. Thanks

 

[catlad]

The easiest thing to do is cover the copping stones with lead sheet.

 

[Sajid Patel]

Thanks catlad. That’s an option.
would something like Cromopol Resin or Liquid Rubber work? the gaps I am sealing at worse 2-3mm.

 

[oldbutnotdead]

That upstand from the grp shouldn't be sealed to the wall- should have a cover flashing over it (lead as per @catlad much the best solution). Your flexible paint options (you forgot Acrypol) might work and might not, grp is tricky stuff to bond to (silicone doesn't bond at all), some of the solvents may react with the grp topcoat (check their suitability before purchase/use)