Hi there. The front wall of my circa 1880 terrace house has developed small dark patches about 3' up from the floor. I know that the wall had a damp course put in in 1984, and that this damp course was treated again in 2004. I'm not suire whether the dark patches that have appeared are damp or not, and I would be really grateful for any advice about this. Could this be residual damp from pre1984?Or could there be aproblem with the plaster? I have checked the plaster on the outside of the wall, and it looks fine.

In article ,
robtiffen writes:

Hi there. The front wall of my circa 1880 terrace house has developed
small dark patches about 3' up from the floor. I know that the wall had
a damp course put in in 1984, and that this damp course was treated
again in 2004. I'm not suire whether the dark patches that have
appeared are damp or not, and I would be really grateful for any advice
about this. Could this be residual damp from pre1984?Or could there be
aproblem with the plaster? I have checked the plaster on the outside of
the wall, and it looks fine.

You haven't provided enough information.
What's "the plaster on the outside of the wall"?
Do you mean render, and is it original or something
which has been added at some point?
What's the decoration on the inside?
Why/how was the damp course treated again last year?

--
Andrew Gabriel