Stained cracks in ceiling

[Martin Bonner]

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?)

[The3rd Earl Of Derby]

Would you have cracks all over your face if you was 100 years old?

The brown stains is a tell tale sign that water is getting in somewhere as the water is mixing with the sh*ite under the floorboards.

this is quite common with baywindow areas when leaking.

[hzatph]

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

[Mary Fisher]

That really surprises me. Have you asked F&B about your problem? We always find them very helpful and free with advice.

We painted the sitting room with discoloured cracked ceilings and walls with F&B water based emulsion. There is no evidence of stain now.

Sorry, all ours are waiting to be used.

Mary

>

[Stuart Noble]

That's why it went out of use half a century ago. Apart from fine art restoration, I don't think it has a use these days.

Just as well. Casein stinks to high heaven if it gets wet. I doubt F&B would have put anything as modern as a preservative in there.

As already suggested, any oil based paint should seal it. I use white undercoat as it's a better key for the emulsion

[The3rd Earl Of Derby]

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.

[Martin Bonner]

The other options for painting the inside of our mud hut (technically, it was part clay lump and part timber frame with wattle and daub infill), were limewash and lime paint - which are even more permeable.

I still feel more comfortable using breathable materials where possible in this much more modern house.

That strikes me as a GOOD thing. It would act as an effective early warning system for damp.

Right. The general consensus is:

1. Check carefully for damp problems.
2. If any found, fix them.
3. Seal remaining stains with oil based paint, and overpaint.

[Pete C]

Might have been nicotine or smoke stain sealed under previous layers of paint. Look up stain blocking for nicotine.

cheers, Pete.

[Stuart Noble]

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

[Stuart Noble]

Pretty much anything you can paint on a wall breathes. We'd all suffocate otherwise. Whether you want it to drink is another matter

You've obviously never smelt it :-)

[The3rd Earl Of Derby]

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

[The3rd Earl Of Derby]

Someone's been standing in the corner quite a long time then. :-)

[Paul Andrews]

There may be body parts hidden under the floorboards of the room above..

[Mary Fisher]

So would I be - and I'd like to know more about yours.

Mary

[Stuart Noble]

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.

[hzatph]

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.