Mould in a rental property: tenant rights
Mould in a rental property in Belgium. Liability, tenant rights, remedies and landlord obligations for treatment.
Causes of mould in a rented dwelling
Mould develops when humidity in the dwelling is excessive. Identifying the source is key to determining who is responsible.
Structural causes (landlord)
- Thermal insulation defect (thermal bridges)
- Water infiltration (roof, facade)
- Insufficient or absent ventilation
- Rising damp
Behavioural causes (tenant)
- Insufficient ventilation of the dwelling
- Drying laundry indoors without ventilation
- Not using the extractor hood in the kitchen
- Blocking ventilation openings
For humidity problems in general, see our guide on humidity in a rental.
Who is responsible
Allocation
| Source of mould | Responsible party | Treatment |
|---|---|---|
| Thermal bridge | Landlord | Insulation |
| Infiltration | Landlord | Waterproofing |
| Insufficient ventilation (design) | Landlord | Mechanical ventilation |
| Lack of airing (behaviour) | Tenant | Airing |
| Indoor laundry drying | Tenant | Dryer, airing |
Expert assessment
In case of disagreement, an independent humidity expert can determine the source of the mould. The cost (200-500 EUR) is shared or borne by the losing party in judicial proceedings.
Tenant’s rights
Available remedies
- Report to the landlord by registered letter
- Request an inspection from the regional housing service
- Formal notice with a repair deadline
- Referral to the justice of the peace if the landlord takes no action
What the tenant can obtain
| Request | Conditions |
|---|---|
| Repairs (treatment works) | Structural origin proven |
| Rent reduction | Proven loss of enjoyment |
| Lease termination | Proven uninhabitability |
| Damages | Proven harm (health, belongings) |
Health impact
Mould can cause respiratory problems, allergies and asthma, especially in children. A medical certificate documenting health problems strengthens the tenant’s case.
For disputes, see our guide on rental disputes.
Solutions and treatment
Immediate actions (tenant)
- Clean visible mould with a suitable product
- Ventilate at least 15 minutes per day
- Do not cover mould without treating the cause
- Use a dehumidifier as a complement
Structural treatment (landlord)
| Solution | Indicative cost |
|---|---|
| Professional anti-mould treatment | 500 - 2,000 EUR |
| Thermal bridge insulation | 1,000 - 5,000 EUR |
| Mechanical ventilation installation | 3,000 - 6,000 EUR |
| Infiltration repair | Variable |
Prevention
The key is a combination of good insulation, adequate ventilation and appropriate tenant behaviour. See our guide on works in a rental and the landlord’s obligations.