Christian McArdle wrote:
Can the injection not be done from the outside?

It is done from the outside. However, it requires the plaster inside
to be replaced, as it will be damaged and contaminated with salts or
something. Besides, it creates additional work for the damp proofing
specialist.

OTOH, you seem to suggest the the inside floor is lower than the
outside ground. That would require tanking up to above the DPC layer,
as there would be no protection against rising and penetrating ground
damp below the DPC layer.


Indeed I'm coming to this conclusion. The back of the house has concrete
all round up to the walls so that tanking job would be a major hassle (ie
expense) as the concrete would have to broken first. Is it done with a
mastic, or something more solid?


Of course, if it is condensation, rather than penetrating or rising
damp, none of this will help. However, the fact it is concentrated
solely in the very bottom of the wall might suggest a penetrating
problem. However, I suppose it could just be the proximity of the
cold ground that causes a condensation problem.


No, I think you're right. The plaster shows years of tide marks so it does
look like it's coming from the ground.


I assume you don't have/do anything silly, like unflued gas heating or
constantly drying clothes indoors?


Nothing like that unfortunately.

Anyone know a reputable damp specialist in North London? Don't laugh.

J