Help with external rendering / sealing

31 Oct 2021
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United Kingdom
We have a wall that is letting in some water around the outside of a window. Please see attached images of inside and outside. I believe it's the brickwork and/or render around the window on the outside. The timber lintel is exposed. We recently sealed the coping stones above and the chimney repointed which helped significantly (see additional photos) but during heavy rain, it still lets in some water and the plaster inside gets damp. Could anyone suggest how to treat the wall/lintel outside?

Many thanks for your help.


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Last edited:
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24 Oct 2020
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United Kingdom
I'd get up and fill the cracks in roof masonry with polymer mastic. Really need to seal that and see how things go as I can see cracks. Mask either side of crack to keep tidy. If that works get up next year and sort out properly.

Storm dry on the outside walls.

Plan B is to cover the outside wall temporarily to see if that sorts out the problem but always start at the top and work down . Frustrating at times tracking down water leaks
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