Frequently Asked Questions

Salt damp is moisture damage caused by mineral salts embedded within masonry.

When groundwater rises through brickwork or concrete, it carries dissolved salts. As the moisture evaporates, those salts remain trapped inside the wall. These salts are hygroscopic, meaning they attract moisture from the air — even when there is no active water source.

Over time, this repeated moisture absorption and drying cycle causes plaster breakdown, paint failure, and surface deterioration.

Salt damp is not simply “wet walls” — it is salt contamination within the masonry structure.

Salt damp is caused by mineral salts entering masonry, usually from the ground.

Common sources include:

• Groundwater rising through porous brick or stone
• Historical rising damp
• Old chimney salts
• Coastal or saline soil conditions
• Long-term moisture exposure

Even if the original moisture source is reduced, the salts can remain active in the wall for years, continuing to attract atmospheric moisture.

The key issue is not just water — it is salt contamination within the wall fabric.

Salt damp typically appears on the lower sections of internal walls.

Common signs include:

• Flaking or powdery plaster
• Bubbling or peeling paint
• White, crusty salt deposits (efflorescence)
• Damp patches that return after repainting
• Damage usually below 1 metre high

Unlike condensation, salt damp damage is usually localised and persistent. The salts remain in the wall and continue to attract moisture, which is why cosmetic repairs often fail.