Rising Damp Perth

Limestone walls and damp

Limestone built Fremantle, Cottesloe and Claremont. It handles moisture well until somebody seals it.

Talk it through

Rising Damp Perth arranges damp assessments across Perth metropolitan area.

Cement render blown off the base of a limestone wall, exposing crumbling stone and white salt crystallisation.
Render failing on limestone. The coating did not fail — it worked, in the wrong place.

Limestone is meant to breathe

A limestone wall takes up moisture and releases it again through its face. That cycle is normal and the wall is built for it. The stone is soft, porous and forgiving — as long as the moisture has somewhere to go.

What sealing it does

Cement render and modern acrylic paints are far less permeable than the stone behind them. Moisture that used to leave through the face now travels higher up the wall looking for an exit, and the salts it carries crystallise behind the coating. Those crystals expand, and the render comes off in sheets. The coating did not fail — it worked exactly as designed, in the wrong place.

The salt problem on the coast

From Cottesloe to Scarborough, salt also arrives on the wind and settles on the wall. Salt is hygroscopic: it pulls moisture out of humid air, so a coastal limestone wall can read damp even in a dry spell. Treating the moisture without removing the salt leaves half the problem in place.

What to use instead

Lime-based renders and mineral paints let the wall keep breathing. They are less familiar to a general painter and cost more, and they are the difference between a repair that lasts and one that has to be done again in three years.

Areas we cover

We arrange assessments across the Perth metropolitan area, including:

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