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Roger Roger is offline
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Default Damp patch on wall

The message
from "TMC" contains these words:

First thing to find out is where the damp is coming from.


Is there a pipe buried in the wall that is leaking?


As it was originally the external wall is it 9" solid brick or is there a
cavity?


If it is a cavity wall it is possible that something is bridging this
cavity
and collecting moisture, though where the moisture is coming from is
another
matter, maybe a leak into the top of the wall?


The damp has to come from somewhere and as it is only a small patch on
both sides of the wall it isn't condensation. Ergo it must be coming
down from somewhere above within the wall. It is quite possible for
water to find its way through voids within the wall and pool at the
point where its flow is restricted or barred but as it would take the
line of least resistance the source doesn't have to be directly above
the damp patch.

If it is rain water then in times of drought the patch should dry out or
at least get dryer. However it could be a pipe that passes through the
wall somewhere above that is leaking into the wall.

If you have defective guttering/downpipes that should be fixed as a
matter of course regardless of whether it is causing your present
problem. Obviously it would be a boon if fixing the drainage fixed the
problem but the defective pointing would need attention too.

--
Roger Chapman