hzatph wrote:
"Martin Bonner" wrote in message
ups.com...
I have a Victorian-Edwardian terrace house with lath-and-plaster
ceilings. The ceilings have cracks in them ; what a surprise!
However, in one corner of the dining room (near the back window), the
cracks have brown stains running along them - perhaps half an inch
wide. I've just repainted the ceiling and the stains have come
straight through the paint.

Any idea what the stains are, and how I get rid of them?

Notes:
- The paint was Farrow and Ball casein distemper, which is close to
being the least impermeable paint known to man.
- There is no sign of damp in the room above, or on the external
wall. The ceiling doesn't feel damp.
- There is no down pipe in the vicinity
- There are one or two places where the vertical mortar lines are
missing (any one got a circular tuit going spare?)

As has been said these are water stains. The only way we managed to
paint over was by using an primer or oil based paint to seal them and
then emulsion over the top. Emulsion alone of any thickness was not
successful. Deal with the water ingress (which may be old and dealt
with already).

HTH

A better solution to the fix is...

Gouge out the surrounding area with a 3 edged profile scraper and fill with
polyfilla and sand down.

--
Sir Benjamin Middlethwaite