Par François Andrieux

Oct 15, 2025 | Tutorial

Tutorial – How does building subdivision work and how do you calculate your margin?

In this tutorial, you will discover step by step how a building subdivision operation works and how to quickly estimate the potential margin using Market Explorer.


🏢 What is a building subdivision?

The principle is simple:
You buy a building made up of several apartments, then you resell each apartment separately.
This type of operation, when well structured, can generate an attractive margin on resale.

Goal: calculate your potential margin. We will illustrate this using a concrete example of a building located on Rue de la Limite in Saint-Josse (Brussels).


Step 1 – Estimate the building’s purchase price

  1. Open Market Explorer.
  2. Select the Market tab, then Secondary residential.
  3. Filter the results to display only income-producing buildings.
  4. Use the Lasso tool to precisely target the neighborhood around Rue de la Limite.
  5. The software shows you a median price per m² for income-producing buildings.
    👉 In our example: €2,200/m².

Step 2 – Estimate the apartments’ resale price

  1. Repeat the same operation, but this time filtering for apartments.
  2. Select the same area again with the Lasso tool.
  3. The software now indicates the median resale price per m².
    👉 In our example: €2,900/m².

đź’° Margin calculation

By comparing the two data points:

  • Purchase price (building): €2,200/m²
  • Resale price (apartments): €2,900/m²

You obtain a theoretical margin of €700/m².


⚠️ Watch out for common areas

When you resell by unit:

  • You cannot add value to all of the m² purchased.
  • Common areas (lobby, stairwell, etc.) cannot be resold individually.
  • This slightly reduces the surface area that can actually be monetized.

➡️ Refine your analysis

You can go further by testing different scenarios:

  • Filter only for studios or 1-bedroom apartments
  • Compare prices per m² by property type or quality level
  • Simulate several subdivision assumptions to choose the most profitable one

âś… Conclusion

You now know:

  • How a building subdivision works
  • How to estimate a realistic margin in just a few minutes
  • How to use Market Explorer to test your assumptions

🎯 Try it yourself on a property of your choice to see whether a subdivision operation is profitable in your area.

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