II have a white powdery substance on different parts of my basement walls, Do you know what this is?

Answer 1

Efflorescence is a white crystalline or powdery, often fluffy/fuzzy deposit on the surface of masonry materials like concrete, brick, clay tile, etc. It's caused by water seeping through the wall/floor/object. The water dissolves salts inside the object while moving through it, then evaporates leaving the salt on the surface.

It can be relatively easy to remove compared to some other stains. Often these salts are water soluble and, if outside, may disappear of their own accord with normal weathering. This is particularly true of "new-building bloom." The water soluble salts can be removed by dry brushing or with water and a stiff brush. Heavy accumulation or stubborn deposits of white efflorescence salts can usually be removed with a solution of muriatic acid and scrubbing (1 part acid to 12 parts water -- this is a real acid, follow precautions on the label). Wet the surface well before and after the solution is applied.

Less common salts, that change their chemical structure during efflorescence formation, require proprietary compounds to remove.

Answer 2

Do not scrub it because it will become airborne. If you do want to clean it, put up a plastic barrier to work in so it does not contanminate the rest of your house. Then put a bleach solution (following all procedures on the bleach bottle) in a pump sprayer and spray the wall then wipe. After that, you will want to get a dehumidifier to get the humidity down on your basement.

Answer 3

One place I lived in had a dried type of salt flaking from the walls, it was due to living near the sea. The whole house was moving and the walls were cracking and releasing this stuff. Not a lot you can do once it gets to that stage apart from re-building the wall. Hope it is as bad as that.

Answer 4

It is probably calcium or salt leching through the wall from the ground on the other side. The only way to get ride of it is to scrub it off and you may have to sand it off and then seal the wall. We had to put a layer of hydro cement on the blocks before we could paint it.

Answer 5

There is damp in the walls and its making the paint do that. Strip off the paint and use a damp sealer before repainting.

Answer 6

Sounds to me like it could be powder mold. Try scrubbing well with a cleaner containg bleach using a stiff brush.

Answer 7

sounds like mold - get it checked out fast as it can cause very serious health problems such a asthma and even brain damage - seriously

Answer 8

Definately mold.

Answer 9

Some type of mold.

Answer 10

mold - try a dehumidifier