White Salt on Brick Walls (Efflorescence) — Why It's There and How to Fix It
That white fluffy powder on your brickwork isn't paint failure — it's salt from moisture inside the wall. Here's how to stop it at the source.
Efflorescence — the white, chalky, sometimes crystalline deposit that appears on brick or plaster — is one of the clearest warning signs of active damp inside a wall. It's not the paint failing. It's not bad brick. It's dissolved mineral salts being carried out of the wall by moisture, then left behind on the surface when the water evaporates.
Why brushing it off doesn't work
As long as moisture keeps moving through the wall, the salts keep coming. Wipe them off today and they're back next month. The salt itself is harmless — it's the moisture underneath that's destroying your plaster.
The real fix
- Confirm the source — usually rising damp (tide-mark) or penetrating damp (post-rain patches).
- Strip loose salt and blown plaster back to sound brickwork.
- Treat the bottom 1m (and outside face) with a chemical DPC like Damp Gone Xtreme.
- Wait 4–6 weeks, then replaster with a salt-retardant render before painting.
Full step-by-step in our internal wall treatment guide, or book our professional service for a done-for-you fix with guarantee.
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