Painting a Damp Cellar

[Richard Aldridge]

We have a Victorian property with a large extremely damp cellar.About 20 years ago the walls were painted with a normal emulsion paint which has lasted extremely well bearing in mind the damp air in the cellar.
I recently had reason to drill a hole in one of the walls which alerted me to the fact that the bricks are absolutely saturated and the water drained from the brick I had drilled almost like a tap.
I have been told these bricks need to breath and paint should not be used which seals the moisture in the walls.This is contrary to what other people on your forum say.Damp proofing oil based paint would probably make matters worse.I believe that in the past all such cellars were limewashed which enabled the bricks to breath.
I should have thought that sealing the bricks will trap moisture within the walls which will eventually travel upwards to escape.
Can anybody offer some advice on this.
Thank you

 

[Bonni]

Not sure about bricks breathing below DPC, especially as far down as a cellar. Normally, you tank the walls in a cellar to make them habitable.

 

[Richard Aldridge]

Thank you
I am sure there must be a reason why they lime washed cellars years ago.
I read somewhere that cellars helped to keep the damp from rising to the ground floor before dpc had been invented
It seems logical that moisture from damp bricks sealed on the inside can only travel up.
Have been advised to fill the cellar with rubble but it is useful for access to gas pipes.
The building was originally a pub.

 

[opps]

I am out of my depth here but AFAIK slate tiles have been used as a DPC for hundreds of years.

Where I live and work in west London, few houses have cellars. They do however have free airflow under the building. I have never considered the possibility that the air flow is to prevent moisture rising up the bricks. I had always assumed that it was to help the moisture from the "mud" to escape. I assume that your cellar doesn't have a bare mud floor though.

Regarding lime wash- wasn't that the only paint type available in the "olden" days, additionally it would have been beneficial when interior walls had lime plaster.

like I said, I know eff all about the subject, you might be better off asking the question in the plastering sub forum. For the record, firms such as Zinsser make cellar paints that are designed to hold the water back- I have never used that particular paint though. When presented with a damp cellar I get a plasterer to tank the walls.

Best of luck.

 

[Richard Aldridge]

Thank you for this.
I think I probably am on the wrong sub forum as my worry is for the deterioration of the bricks being continually saturated with water.
I know that old porous bricks do eventually break up
The building has an injected chemical damp course which was done many years ago by the previous owner and which I think needs replacing.
Incidently the exterior of the building is rendered with cement and painted with masonry paint.
A surveyor advised painting with plialite oil based masonry paint but a builder told me that paint is totally unsuitable for a damp old building built in nine inch brickwork
It was the builder who told me that old bricks need to breath