DIY Doctor UK DIY Forums

Hello,

I have had a problem with penetrating damp every time it rains for about 6 months now on the bay window wall. This will appear as dark patches on the wall within about 8-12 hours of it raining depending on how "heavy" the rain is. The patches appear in a concentrated area at either side of the wall but too high from ground level for rising damp. I have been through all the possible solutions that I can find online but the problem still persists.

So far the below work has been carried out and completed and then checked for the standard of work which is all good:

:- New Felt and Eaves trays installed with all broken tiles removed and replaced with new ones on the bay window roof.
:- Patch pointing work on the bay window wall including the removal of the virgin media box with this filled in with mortar.
:- Windows re-sealed and ensured there are no gaps for water to enter the wall/windows.

The house has solid walls with no cavity and has brickwork similar to Flemish Bond, the house was built in approximately 1905. It was repainted (Externally) about 2 years ago but this was done with the same paint and by the same person as previously and has never caused any problems previously to my house or any of the neighbours who use the same person.

I am at a loss to how the water is entering the walls or if it could be potentially down to cold spots or anything else. However the only solution currently is to turn on the dehumidifier whenever it rains but ultimately this needs resolving sooner rather than later and is costing a lot in electricity bills in the meantime (Not mentioning the damage to the wall).

Any advice/help with this would be greatly appreciated.

Thanks,
Andrew.

We would like some pictures please, to give you an accurate diagnosis

Hello,

Please see attached pictures:

I hope this is helpful.

Thanks,
Andrew.

damp patches usually occur when water tracks down from a crack or penetrates through the wall.
In this case, if its not the window then it could be the sill it sits on. It may be water holding on the edges of the sill and tracking back, Try chiseling out the mortar each side of the sill and filling with silicone, And spray the wall with aquaseal silicone solution