Plastering an old chimney breast.

[Somebody]

Hello.

We've three old coal fireplaces in our house that we're in the process of removing and bricking up. My father (who was a builder about thirty years ago) is going to do the brickwork and replastering. I know he'll do a good job but he reckons he's going to have to use cow manure before plastering, to stop the soot seeping through the plaster etc. I realize this is what they used to do years ago, but I'd rather avoid it if possible. We've got to live in it and we don't particularly want to have to put up with the stink. So, does anyone know of anything else he could use to solve the soot problem, other than manure? And would you know where to get it. I've looked through screwfix and other sites but turned up zilch.

Thanks in advance.

[Phil L]

Milk.

Seriously, paint over the sooty parts with milk, then plaster, although this may not actually stop the yellow stains coming through the plaster - there is nothing you can put on that will stop that - but it will allow the plaster to adhere to the soot, without it, it won't stick.

That said, I don't use any of these anymore, I just dryline over the area, fill in the edges with browning or bonding, then skim the lot, avoid using blobs of DL adhesive on the soot - they won't stick neither

[Somebody]

Cheers Phil. It looks like we're going to have to do the entire breast then, if drylining's the best option. Not just a patch up of where we've ripped the old fire place out.

[Phil L]

You don't need to dryline the entire wall, unless you want/have to....just cut back the old plaster (fairly straight if poss) about 6 inches all the way around (this gets rid of any 'lips') and affix half a board or whatever size fits in - if the old plaster is very thin it may not be possible, IE the p-board will be proud of the existing plaster, but if it's borderline (only a few mm spare), simply mix your drylining adhesive quite wet - this will compress back further, conversely, if the plaster is an inch or more thick, you can mix it stiff and put larger sized blobs on to bring it out.

[FKruger]

Oh come on just plaster over the bricks you are unlikely to have any problems. If you get a small yellow patch just paint over it with an oil based paint and its gone.

[Stuart Noble]

I certainly wouldn't paint anything indoors with milk. One of the worst smells on earth

[FKruger]

Cow manure plaster is worse I imagine. Maybe he could plaster his whole house in manure then paint over that with milk to really pile on the added value.

[Phil L]

I've never heard of the manure method before, but milk has been used for years...neither smell like you would imagine, because they are behind the plaster, IE they are apinted over the soot, then wet plaster is applied, once the plaster is set, it is then skimmed, then painted or wallpapered...both methods I believe, are used to kill the soot, how they work I don't know, but water / PVA won't do the job.

As an aside, I had a pint of milk leak all over the carpets in the car a few weks ago, it stank to high heavens, but I assume this was the bacteria etc and christ knows what else breeding in the carpets, I can't imagine that milk soaked into sooty bricks will contain many, if any living organisms....although I'm not a milkologist. :-p