On 10 Sep 2005 12:24:47 -0700, wrote:

In 1994 I replaced a coal boiler with a gas combi. In 1999
water was running down the living room wall. After eliminating
the obvious candidates, slates, flaunching, pointing, flashing
etc I was left with only one option - the flue (the products of
combustion are carbon dioxide and water). This proved to be the
case. It had been damaged on installation and, for five years had
been pumping water into a 75cm shale wall with soil/lime mortar.
The flue was replaced.
.
Six years on, the wall is still not completely dry despite my having,
this year, chopped off and repointed the bottom metre of external
rendering and run a 2kw fire and a dehumidifier in the sealed room for
8 - 10 hours a day.

Are you sure you don't have another source of damp?

DG