Can you paint over mould or damp inside an Algarve home?

Separate the mark from the moisture source

A dark corner may be linked to condensation and weak airflow; a local stain can follow a roof, plumbing or seal failure. Photograph the whole wall, the room and the exterior area behind it. Note whether the mark changes after rain, showers, cooking or periods when the house is closed.

A moisture reading can support the inspection, but one number does not diagnose the source. The pattern and its history matter.

• Show windows, external walls and nearby plumbing
• Record musty odour, peeling, salts or soft plaster
• Compare the same point after wet and dry weather

Do not seal an active problem under paint

The US EPA advises against painting or caulking mouldy surfaces: the water problem should be corrected, hard surfaces cleaned and the material dried first. Porous material that cannot be cleaned and dried may need specialist removal or replacement.

Large, hidden or recurring growth, extensive water damage and any health concern should be assessed by an appropriate specialist before decoration begins.

Prepare the coating decision

Once the source is controlled, check that the wall is firm, clean and sufficiently dry. Remove loose coating, repair defects and follow the selected primer and paint technical sheets. A stain-blocking or mould-resistant product can be part of the system, but it cannot replace moisture control.

Use a small representative area where compatibility is uncertain, and record the products and dates used.