We have purchased an old detatched property built approx 1930`s, it has 3 chimney`s, 2 on external wallls, and 1 internal. After heavy rain, large damp patches appear on the 9" solid internal walls, around the area of the chimney breasts,and on both sides of the internal chimney breast. The lead flashings have been replaced, the chimneys have been re-pointed and sprayed with water sealer. The original roof, is obviously passed its sell by date, but the attic, although cold, is dry, with no evidence of leaks. The external walls are rendered at bedroom level and brick at ground floor level.
We have had the roof inspected by several people, and opinions range from leaking render to a complete new roof. I should add that the chimney`s have`nt been used for years, and we were aware of damp patches when we bought the property, although we had no idea how difficult it would be to eradicate the problem.
I can believe we have a leak in one or two places, although i have sat in the attic during heavy rain and have seen no leakages, but cant understand how 3 chimneys in 3 sperate bedrooms are showing damp patches after heavy rain.
We are considering demolishing the internal chimney and removing the plaster on the affected walls of the other two chimney`s and painting on bitumastic paint, then replastering.
If anyone can advise us how to beat this problem, we would be eternally grateful

1) Could you tell us what sort of caps, if any, are on the chimney pots?

2) Could you get us external photos?

John

We have had a log burner flue installed in one chimney, and a gas flue in the other,they are fitted with the recommended caps, will take some photos and add them to the description.

The latest idea to stop the damp on the chimney breast, is to fit a lead dpc tray to both chimneys. The possible problems in doing this, could be the fact that the chimney breasts are exterior, and also that both have stainless flue liners fitted. A bricklayer friend of mine thinks it unlikely that a waterproof seal can be achieved, as the tray is normally fitted to a clay liner. Does anyone know if this can be done?