Condensation inside disused chimney causing damp issue in ceiling + how to insulate on internal side?

[Mike]

8 hours ago, GeoffSmith said:

I decided to test them with a moisture meter while I was there, and the inside of every brick I could reach was a consistent 18% moisture. The other side of the bricks, and all bricks outside of the chimney registered 6-8%.

'Moisture meters' don't measure moisture, they measure electrical resistance, so no comment on the specific figures. However the presence of the previously mentioned hygroscopic salts would no doubt account for the difference between the inside and the outside of the brick, since they would change the electrical conductivity/resistivity (and be mainly present on the inside).

 

8 hours ago, GeoffSmith said:

Oh, and the bricks could be removed with nothing more than a wiggle

Yes, that does happen. I guess lime mortar would have been used, with as little lime as as the builders could get away with.

 

Edited September 11 by Mike