Paint suitable for the cellar

[natureplantar101]

Hi first post as i was looking online and came across this website so thought i'd join and ask....anyway what kind of paint would you use in a cellar ? we have just bought a house and i'm wanting to paint the cellar white, i know that the cellar is the "breathe room" of the house so i cant use normal masonry paint on the bricks without re-plastering the whole house once the damp rises.. i was thinking a chalky breathable paint if there is such a thing ? any help greatly appreciated :) oh and we have about £20 to spend per can of paint if that helps

[natureplantar101]

anyone ?

[fortyplus]

My house has a painted cellar and it looks like... a damp dirty painted cellar. I wouldn't do it

[natureplantar101]

if i used chalk based paint it would be ok though ? ive done reaserch since painting and found a company that makes paint especially for old stone cottages and cellar walls. what paint did you use ?

[fortyplus]

Hi - not me - it was already done so I'm not sure what sort of paint. Whatever it was the damp brown stains manage to show through it

[80sMum]

I would use Zinsser Watertite for a cellar.

[Spindelina]

Are the walls already painted?

If not, or if you think they were painted a long time ago (so they will already be lime), you could limewash. Especially if the walls are damp. Might not come under your budget, though.

[MehsMum]

If the walls need to breathe, I would second the suggestion of limewash. It's not cheap though.

[natureplantar101]

Not they are bare and damp would never put anything watertight on the jesus DH would kill me the walls need to breathe and leak water just want them to look a bit brighter as its so dark

[80sMum]

Why would cellar walls need to breathe? They will never dry out, as below ground level. You would simply be letting more damp come through, surely? It will always be damp and prone to mould in there.

[PigletJohn]

water enters cellar walls from the ground. Ventilation allows the water to evaporate from the walls, into moving fresh air that is not already saturated.

If evaporation and ventilation are faster than water entering, the cellar will be cool and not very damp.

If evaporation or ventilation are obstructed, dampness will increase and the walls and floor will get excessively wet, and you will get mould and rot.

So a breathing coating (if any) is preferable.

[SWIMTHECHANNEL]

H'mmm. The back wall of my kitchen is built partially into a hill and the paint has gone all 'salty' at the bottom. Is this because I needed a breathable one?

[PigletJohn]

it will be efflorescence.

In a habitable room, you may want to put more money and effort into damp-proofing the wall, than if it was just a cellar. You could start by scraping off the mineral crystals (don't wet them) and the bubbling paint, and try to ventilate that area, e.g. by not putting furniture against it.

If there is wooden floor, joists or skirting, it will be liable to rot. You can probably pry off skirting reasonably easily. Look for any signs of overspilling gutters, leaking pipes, defective drains that will make it worse. If it is a wooden floor, look for airbricks and clear out the dust and cobwebs or other obstructions . You need maximum possible ventilation of the subfloor.

Get a pencil and draw round the outline of the damp, and pencil the date against it. Then you will see if it gets bigger or smaller (e.g. after rain).

If you feel impelled to paint it, you can use Dulux Trade Supermatt Emulsion which is breathable (it is not very durable or washable, as it is non-vinyl. AFAIK the smallest tub is 5litres. PBW is cheapest.

If you have any opportunity to work outside, e.g. sloping any paving so that rain runs away from the house, or lowering the ground level, that will help. I presume your house is rather old, or has been amateurishly altered.

[SWIMTHECHANNEL]

Thank you PJ, as usual.

It''s 1700s cottage, stone-built actually into the hill (there's a castle on top!).

There's no damp patch as such, just these salty crystals on that end wall. I don't know if a dehumidifier would help? Or lime paint?

[PigletJohn]

the crystals are what's left after the penetrating water has dried off the surface.

If it is not visibly damp, that's good, it means it is evaporating from the front about as fast as it comes in from the back.

Improved ventilation will speed up evaporation and it will be drier.

It probably has lime plaster. If it is unpainted it will dry a bit better, but you can use a permeable coating for appearance. Brush or scrape off the efflorescence, some of the paint will probably come off too. Don't try to wash it off wet as it will dissolve in the water and soak back into the wall.

[SWIMTHECHANNEL]

Thank you!

[natureplantar101]

The reason the walls need to breathe is because if the water doesn't come out the cellar walls it will rise up and damage the whole building its what cellars are made for the house was built in 1904 people used to store coal and dry foods in them but not much else its was considered more of an air conditioner to them you open the door and all the cold air rushes out and it absorbs any water in the foundations and releases it into the cellar so it cant harm the upper rooms think i might just wipe them down with some disinfectant and dust and see what it looks like after