Mould in the home: how to spot it before you bid in Denmark

The short answer: mould is a symptom of moisture, not a defect in itself. Chase the moisture source rather than staring at the stain. It grows where a surface has stayed damp: cold exterior walls behind furniture, bathrooms, basements and crawl spaces. Visible mould is something to investigate, not proof of an expensive fault.

How to spot damp and mould at a viewing

Look for dark patches, flaking plaster, salt efflorescence and a musty smell, especially in the basement and behind furniture on exterior walls. Always trace a patch back to its source: the roof, plinth, pipes or poor ventilation. Take photos and note where it sits, so a surveyor can assess it afterward.

What the condition report covers (and does not)

The tilstandsrapport describes damage and possible damage, but only what is visible and immediately accessible. Mould behind furniture or inside the structure can therefore be missing, so a clean box means “no visible signs”, not “dry house”. If mould is marked, get the cause and extent clarified before you bid.

Health: when it matters

Prolonged time in damp rooms can cause irritation of the eyes, nose and throat, a blocked nose, coughing and wheezing. The larger and more moisture-driven the growth, the more reason to act. A small, dry surface patch is rarely a health problem.

Who pays, and what it costs

When buying an owner-occupied home, mould is generally your risk after completion unless otherwise agreed, so the cost belongs in your bid. Remediation ranges from a few thousand kroner for a small surface patch to tens of thousands for larger, moisture-driven growth. If you need to know the level, a mould test can answer before you commit.

Bid, negotiate or walk away

Surface mould with a known, cheap cause is often a negotiating point, not a dealbreaker. Hidden or recurring mould from a structural fault, such as a leaking roof or damp in a basement wall, is more expensive and more uncertain. Have it assessed by a building surveyor before you bid. If the cause cannot be found, it is reasonable to ask for an investigation or move on.

The point is not to find a perfect house. It is to know the cause and cost of the moisture before you commit. Paste the listing into Heimer, and we gather the report’s findings and the questions you should ask in one place.