Damp walls

See the signs.
Understand the cause.

Salt deposits, flaking plaster or a musty smell: damp walls leave visible signs. We assess the cause and explain how your building can become dry again.

Recognising the signs

How damp walls
show themselves.

Damage can appear on both the inside and outside of a building. Discolouration and flaking paint or plaster make the moisture visible.

Salt efflorescence (saltpetre / nitrates)

Dissolved salts travel from the ground into masonry with moisture. As the water evaporates, the salts crystallise at the surface.

Flaking paint and plaster

Paint flakes and plaster comes away. While moisture continues to enter, even recently renovated surfaces can become damaged again.

Sanding and crumbling plaster

The plaster surface loses cohesion. Fine grains come loose, leaving sandy patches that crumble away.

Localised voids behind plaster

Plaster can detach from the surface beneath it. Small hollow areas form between the plaster and the masonry.

Moisture paths in a building section 123
  1. 1
    Rising damp

    Ground moisture enters the pores of masonry.

  2. 2
    Lateral moisture

    Walls in contact with soil can absorb water.

  3. 3
    Condensation & leaks

    These causes require other measures.

Different causes.
Different responses.

Rising damp and moisture entering from the side

Older buildings may have no damp-proof courses. In newer buildings, these can be defective or inadequate. Materials in contact with the ground absorb moisture, which rises through pores by capillary action or enters the wall laterally.

Leaking pipes and inadequate ventilation

Leaks or condensation on cold surfaces can also cause damp walls. These causes need different measures. Our building analysis identifies where the moisture comes from.

Start with a building analysis

Dry walls start with
understanding the cause.

Inside the masonry

Water moves.
Salts remain.

Porous building materials absorb water. Missing or damaged damp-proof courses allow moisture to keep entering.

Salts and minerals travel from the ground

Moisture carries dissolved salts and minerals into masonry. Water evaporates at the surface, leaving salts behind to crystallise. This repeated process can damage plaster and paint.

The resulting damage includes salt efflorescence (saltpetre / nitrates), flaking surfaces, sanding and localised voids behind plaster. Discolouration and flaking paint or plaster can appear inside and outside. Repainting alone does not stop an ongoing moisture source.

Water and salts in masonry 123
  1. 1
    Water rises

    Dissolved salts travel into the wall with it.

  2. 2
    Moisture evaporates

    Water leaves through the surface.

  3. 3
    Salts remain

    Crystals can damage plaster and paint.

The consequences

What damp walls
can lead to.

Continuing moisture transport can damage the building fabric, cause recurring costs and affect living conditions and health.

Flaking paint and plaster on a facade
Flaking paint and plaster on a facade
Damp walls in a storage cellar
Damp walls in a storage cellar
Discolouration on a cellar wall
Discolouration on a cellar wall

Costly building damage

Repairs often do not last while walls remain damp. Short renovation cycles lead to repeated investment in the same surfaces.

High heating costs

Saturated exterior walls provide less insulation. Greater heat loss can increase heating demand and energy costs.

Reduced quality of living

Damp interior walls and musty smells affect how rooms feel. Cellars and storage rooms become less usable.

Health risks

Fungal spores and mould can spread on damp wall surfaces. Mould can affect the airways and trigger allergic reactions. Both the moisture source and any existing mould need professional assessment.

Start with a building analysis