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Stuart Noble

wrote:
Stuart Noble wrote:
Ed_Zep wrote:

This is an internal wall, though.
Then it's either rising damp which the dpc should cure (claim under the
guarantee if it doesn't dry out in the specified time). Or you have a
plumbing leak. Is this a kitchen or what?

Causes of damp on internal walls, in order of likelihood:

1. condensation. Cause: interior RH too high. Solution: find cause/s of
high RH and fix em.

Not very likely in the current weather conditions I'd say and, even in
winter, usually due to a lack of heating.

2. Faulty roof or rainwater goods dumping water onto the wall.
Solution: clear gutters and hoppers, check rain drainage works ok, or
fix roof.

Possible if there's a leaking valley or something on the roof but that
should be obvious at the top of the wall

3. Salt contamination: this tends to happen to chimneys mostly, but can
also result from iron pipe fixings or spillages. Solution: remove and
replace plaster

4. Peeing: animal or small child peeing on wall. Solution: retrain.

5. Rising damp: it does exist but is rare. If every other cause has
been ruled out, and every necessary measure taken, inserting a dpc just
might work. Almost all rising damp diagnoses are false.

Agreed, but rising damp has to be considered on a wet internal wall in
the middle of summer. I'd be looking for a leak but we don't as yet know
the OP's setup.

NT