DIY Doctor

Penetrating damp or problem flat roof leaking into utility

Postby wheldcj » Sat Jan 23, 2021 9:41 am

Any help gratefully appreciated.

We have major rainwater leaks below a flat roof into utility/lean to. To give some background we have always had leaks and actually had a new flat roof in May last year to resolve. However it has made it worse.

As our gable end is very open to driving rain I don’t know if issue is water entering via roof or through cavity. To compound matters two roofers have different advice. One suggest poor roof installation is the fault and other says roof is fine and suggested rendering. Our own roofer is denying his workmanship is to blame and says our brickwork is porous.

Internally in main house we have occasional damp problems above a window. The window itself is fine so some water is entering cavity.
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Simply Build It

Postby stoneyboy » Sun Jan 24, 2021 9:53 pm

Hi wheldcj
Assuming the new roof is sound the most likely problem will be linked to rain penetrating the bricks on the gable end. Ideally a cavity tray should have been installed when the lean to extension was constructed - presumably it was not. You could try coating the gable wall with silicone brick sealer and see if this reduces the problem but there must be a lead flashing cut into the lower brick course for the sealing to be effective.
Regards S
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Postby wheldcj » Mon Jan 25, 2021 6:36 pm

Thanks Stoneyboy. I think you are right! Appreciate it
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