"Stuart Noble" wrote in message
...
The3rd Earl Of Derby wrote:
Stuart Noble wrote:
The3rd Earl Of Derby wrote:
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.

IME the stains will bleed through anything water based, including
filler

Why do you think I said gouge out the surrounding area?

You may have to gouge out rather a lot if you're looking for the source of
the stain. Can't see what filler is going to achieve in these
circumstances.

I agree with Stuart - doesn't help. Salts have been left in the surrounding
damp plaster and these need to be removed (extensive) or sealed. Repairing
the crack itslef is best done as advocated by gouging and filling.