Our house is circa 1860. There was obviously a long standing chimney dampness problem when we move in as both stacks were crumbling towers of dust. However, hubby has rebuilt stacks to exacting standards - flashing, brick work and flaunching. I would have expected the damp patches to dry out (albeit very slowly). But, the damp meter we have got indicates that the damp patches worsen with heavy rain. Stacks are open, so was considering a cowel - but internet research suggests that this won't solve the problem. House was also re-roofed and the stacks must be water-tight. Chimneys are not currently used and I suppose ventilation could be improved slightly but still the rain-related ingress is worrying. Any suggestions would be gratefully received - Thanks

flossy, August 2010

If the work done by hubby, has been good, then it is likely that water ingress is from non use of the chinmey and rain water is running down the inside of the old flu, which may be broken or cracked,allowing the water to enter the wall.
COVER the pot with a piece of lead, solid top cowel etc, and this should sort the problem.

Davymac, August 2010