What you need to know
- A hygrometer measures air humidity; a material meter estimates moisture in compatible surfaces.
- Compare readings across similar areas instead of relying on one universal number.
- Persistent damp, mould or deteriorating finishes should be investigated before decoration.
Use your own measurements
BricoDato tools help turn the guide into quantities, kWh, cost or a project plan.
Air humidity and wall moisture are different
A room can have normal relative humidity while one wall remains wet because of a leak or water ingress. Use the right measurement for the question you are asking.
Look for the cause
Note whether marks appear after rain, near plumbing, on cold corners or behind furniture. Condensation behaves differently from a plumbing leak or façade penetration.
Use measurements comparatively
Material meters vary by substrate. Take several readings and compare the suspect area with a dry area of the same material.
Know when to escalate
Large mould growth, repeated damage, salts, crumbling plaster or damp near electrical installations deserve professional diagnosis.
Final check
Before buying material or doing the work, review the assumptions and technical limits that matter for your specific product, room or installation.
- Record date, location and conditions with each reading.
- Compare like-for-like areas.
- Identify the likely moisture source before redecorating.
- Seek professional help if damage persists or safety is involved.
Keep a small job sheet
Record the measurements, product reference, technical values you used, date and final result. For maintenance or diagnostics, also note the conditions at the time. A short written record makes future comparisons much more reliable.
Turn the guide into a decision
Use your measurements and the manufacturer’s technical data. If the decision affects fixed electrical work, structure, hidden leaks, refrigerant systems or another safety-critical installation, consult a qualified professional.