Humidity in the home is a common problem in Luxembourg, particularly due to the oceanic climate with high rainfall and significant temperature variations. Damp patches, mould, musty smells: this guide helps you understand the causes, diagnose the issue and choose the right solution.
The Different Types of Household Humidity
1. Rising Damp (Capillary Action)
Rising damp occurs when groundwater travels up through walls via capillary action. This problem mainly affects older homes in Luxembourg.
Signs:
- Damp patches on the lower part of walls (up to 1.5 m high)
- White salt deposits (efflorescence)
- Flaking paint or plaster
2. Condensation
Condensation results from excess moisture in the air that settles on cold surfaces, very common in well-insulated but poorly ventilated homes.
Signs:
- Misted windows
- Black mould in corners and on wall/ceiling junctions
- Persistent musty smell
3. Water Infiltration
Infiltrations come from waterproofing defects in the roof, facade or window frames, often worsening during heavy Luxembourg rains.
Signs:
- Localised damp patches appearing after rain
- Water rings on ceilings or walls
Quick Diagnosis Chart
| Type of Humidity | Location | Main Cause |
|---|---|---|
| Rising damp | Bottom of walls | No damp-proof course |
| Condensation | Windows, corners | Poor ventilation |
| Infiltration | Localised (roof, facade) | Waterproofing defect |
Solutions and Costs
For Rising Damp
Hydrophobic resin injection:
- Cost: €100-150 per linear metre
- Effectiveness: Very good, guaranteed 10-30 years
Peripheral drainage:
- Cost: €3,000-8,000
- Effectiveness: Excellent in combination with injection
For Condensation
Single-flow ventilation (VMC simple flux): €1,500-3,000 installed Dual-flow ventilation (VMC double flux): €4,000-8,000 installed (eligible for Klimabonus grant)
For Infiltrations
Roof repair: €40-200/m² Facade waterproofing treatment: €15-35/m²
Prevention Tips
- Ventilate daily: Open windows for 10-15 minutes every day
- Use the extractor hood when cooking
- Maintain a stable temperature: 18-20°C throughout the home
- Maintain regularly: Check roof and gutters at least once a year
When to Call a Professional?
- Mould covering more than 1 m² of surface area
- Persistent musty smell despite ventilation
- Structural deterioration of walls or floors
- A recurring problem that keeps coming back
Cost of professional diagnosis: €200-500
Find a Humidity Specialist on tack.lu
More than 50 humidity and damp specialists are listed on tack.lu in Luxembourg.
FAQ
What is the most common cause of humidity in Luxembourg?
Condensation due to insufficient ventilation is the most common problem, particularly in well-insulated but poorly ventilated homes. Modern energy-efficient builds are especially susceptible.
Is a dehumidifier enough?
A dehumidifier treats the symptom but not the cause. It is a temporary solution and should be combined with proper ventilation measures.
Are there financial grants available?
Yes, certain works (dual-flow ventilation, insulation) are eligible for Klimabonus grants from the Luxembourg government.
How long does a rising damp treatment last?
A professional resin injection treatment typically comes with a 10 to 30-year guarantee when carried out correctly.
