My apartment that I have lived in since it was built (now 18
months) has developed marks on the painted plaster board. I only
noticed these marks after about 15 months from when the apartment was
first built. The only way to describe them is that someone has put
there fingers in grease and created a speckled effect all over the
wall. It has only happened on the walls that are on outer walls but
these are not Westerly facing (apparently this wall is normally the
coldest and attracts moisture). I did have a picture frame on one of
these walls and after taking it off the back of it was covered in
The apartment is under NHBC 10yr (not that it counts much) and
I’ve had the builders out but they have been unable to explain
it apart from lack of ventilation \ drying. They recommended treating
it with a stain block type substance and decorating but I'd rather
sort out what the problem is, any ideas?
It does sound like ventilation/condensation. What to you do to
ventilate? Do you keep window trikle vents open? Do you open
windows? Do you use an extracter fan in bath/shower room and
extracter hood over hob when cooking?
However, I am surprised that a new place would get condensation
over the last 3 months. I wonder if there's no insulation in the
outside walls, and/or if you have some abnormal source of water
vapour in the building. Is there a damp smell? Might be worth
spending a couple of quid on a humidity guage (a cheap greenhouse
one would do) so you get some idea what the humidity is inside
My guess is a bridged cavity or failed damp proof course. If the effect
stops at a certain height, then it may be the DPC, if not, it is more likely
a bridged cavity. This could be lack of care not to drop mortar on the ties,
or could be an inappropriate insulation material (such as open cell foam)
that allows water to pass through. If the entire wall is coated, then the
insulation is more likely, as the bridged wall ties would cause a very
The effect does not stop at a certain height, although it is quite bad
at one particular spot at the top of the wall. Previously I mentioned
it was speckled in this instance it is constant mark for aprox 5cm
wide and 500cm long.
I live on a 1st floor apartment so I'll check with my downstairs
neighbour if they have suffered a similar effect. The only I can
mention is that my neighbour across the landing suffered a similar
effect as well.
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