Converting a house into rental flats
How to convert a house into multiple rental apartments in Belgium. Planning permission, standards, co-ownership, EPC and profitability.
- 01 The project
- 02 Required permits
- 03 Works and standards
- 04 Profitability
The conversion project
Jean-Marc bought a large 220 m2 house on 3 levels in Charleroi for 180,000 EUR. Instead of renting it out whole (estimated rent: 900 EUR/month), he wants to divide it into 3 independent apartments:
| Unit | Area | Estimated rent |
|---|---|---|
| Apartment 1 (ground floor) | 70 m2 (2 bed.) | 600 EUR |
| Apartment 2 (1st floor) | 75 m2 (2 bed.) | 620 EUR |
| Studio (2nd floor) | 40 m2 | 400 EUR |
| Total | 185 m2 | 1,620 EUR/month |
The gain: 720 EUR/month more than renting the house whole. But the project involves major works, permits and standards to comply with.
Dividing a dwelling into multiple units requires a planning permission in all three Regions. Without a permit, letting is illegal and the landlord faces fines and an obligation to restore the original state.
Required permits
Planning permission
| Region | Authority | Average timeline | Cost |
|---|---|---|---|
| Brussels | Municipality + Urban.brussels | 3-6 months | 50-500 EUR |
| Wallonia | Municipality + delegated officer | 2-4 months | 50-250 EUR |
| Flanders | Municipality + Stedenbouw | 2-4 months | Variable |
The permit verifies that the division complies with urban planning standards: minimum area per dwelling, lighting, ventilation, parking spaces, compatibility with the local plan.
Co-ownership
If the 3 apartments share common areas (entrance hall, staircase, garden, parking), a co-ownership must be created:
- Base deed: description of lots, private and common parts (notary)
- Co-ownership regulations: house rules, charge allocation
- Building manager: appointed by the general assembly of co-owners (Jean-Marc alone at first)
- Cost: 2,000-4,000 EUR (notary)
Letting permit (Wallonia)
In Wallonia, the letting permit is mandatory for dwellings under 28 m2 (the 2nd-floor studio at 40 m2 is exempt but the threshold should be verified).
EPC
Each unit must have its own EPC certificate. Cost: 150-350 EUR per unit.
Works and standards
Conversion works
| Item | Average cost |
|---|---|
| Unit creation (partitions, doors) | 5,000-15,000 EUR |
| Additional kitchens and bathrooms | 10,000-25,000 EUR |
| Electricity (3 meters, compliance upgrade) | 5,000-10,000 EUR |
| Plumbing (3 supplies, drains) | 3,000-8,000 EUR |
| Acoustic insulation between units | 2,000-6,000 EUR |
| EPC and certificates | 1,000-2,000 EUR |
| Architect fees + permit | 3,000-8,000 EUR |
| Total | 30,000-75,000 EUR |
Standards to comply with
| Standard | Requirement |
|---|---|
| Minimum area | 12-18 m2 per person depending on Region |
| Ceiling height | 2.20 m minimum |
| Natural light | Window = 1/6 of floor area |
| Ventilation | Compliant system per unit |
| Electricity | RGIE compliant + meter per unit |
| Acoustic insulation | Minimum sound reduction between units |
| Smoke detectors | Mandatory in each unit |
| Independent access | Each unit must have its own entrance (or access via common parts) |
See our guide on mandatory diagnostics.
Project profitability
Calculation for Jean-Marc
| Element | Amount |
|---|---|
| Purchase price | 180,000 EUR |
| Purchase costs (14%) | 25,200 EUR |
| Conversion works | 50,000 EUR (estimate) |
| Co-ownership + permit costs | 5,000 EUR |
| Total investment | 260,200 EUR |
| Annual rent (3 units) | 19,440 EUR |
| Annual charges (property tax, insurance, maintenance) | -3,500 EUR |
| Net annual income | 15,940 EUR |
| Gross yield | 7.5% |
| Net yield | 6.1% |
Compared to 5.3% gross yield if the house were rented whole (900 EUR/month). The gain is +2.2 percentage points of yield thanks to the conversion.
Risks
- Additional works: budget overruns are frequent (plan for +20%)
- Vacancy: managing 3 units = 3 times more turnover
- Management: more complex than a single rental
- Future standards: EPC and compliance standards evolve
Advice
A rental management software is essential to manage 3 leases, 3 tenants, 3 deposits and 3 meters. To create the 3 compliant leases, use our online lease generator. For other cases, see our case studies or the guide on rental property investment.