White deposit below DPC internal brick wall

[Little Plumb]

This is occuring in an internal passageway in a block of flats. The floors are solid and carpeted and this is an internal wall. I assume the dpc is stopping the white stuff rising further up the wall.

Anyone any ideas what might be causing the problem and what the white stuff actually is?

further images in album

Untitled

• Little Plumb
• 16 Jan 2009
• 1

 

[^woody^]

Efflorescence, or soluble salts bought to the surface as moisture evaporates

 

[not5diy]

Hi,
As the last respondant says, these are salts usually, but not invariably, Sulphates. They are common below DPC level particularly where common bricks or facing bricks have been used below DPC level or where the mortar mix is weak. As long as no physical disruption of the floor surface is present it is not a problem. They can be treated with a salt neutraliser or water proofed if the small damp band poses problems to floor coverings.