In this tutorial, you’ll discover step by step how a building unit-splitting deal works, and how to quickly estimate the potential margin using Market Explorer.
🏢 What is building unit-splitting?
The principle is simple:
You buy a building made up of several apartments, then resell each apartment separately.
When well structured, this type of deal can generate an attractive margin on resale.
Goal: calculate your potential margin. We’ll illustrate this with a concrete example on a building located on Rue de la Limite in Saint-Josse (Brussels).
Step 1 – Estimate the building’s purchase price
- Open Market Explorer.
- Select the Market tab, then Secondary residential.
- Filter the results to show only income properties (“immeubles de rapport”).
- Use the Lasso tool to precisely target the neighbourhood around Rue de la Limite.
- The software shows you a median price per m² for income properties.
👉 In our example: €2,200/m².
Step 2 – Estimate the resale price of the apartments
- Repeat the same operation, but this time filtering on apartments.
- Select the same area again with the Lasso tool.
- The software now shows you the median resale price per m².
👉 In our example: €2,900/m².
💰 Calculating the margin
Comparing the two figures:
- Purchase price (building): €2,200/m²
- Resale price (apartments): €2,900/m²
You get a theoretical margin of €700/m².
⚠️ Watch out for common areas
When you resell unit by unit:
- You cannot monetise the entire purchased surface area.
- Common areas (hallway, stairwell, etc.) cannot be resold individually.
- This slightly reduces the surface area you can actually monetise.
➡️ Refine your analysis
You can go further by testing different scenarios:
- Filter only on studios or 1-bedroom apartments
- Compare price per m² by property type or standard of finish
- Simulate several splitting hypotheses to choose the most profitable one
✅ Conclusion
You now know:
- How building unit-splitting works
- How to estimate a realistic margin in just a few minutes
- How to use Market Explorer to test your hypotheses
🎯 Try it yourself on a property of your choice to see whether a unit-splitting deal is profitable in your area.