When do you need a permit for your extension?
An extension (aanbouw) adds space to your home — for example, an extra room on the side or rear. Whether you need an environmental permit (omgevingsvergunning) depends on the location, dimensions, and type of structure. In many cases, a rear extension is permit-free as long as you stay within the national limits of the Environment Buildings Decree (Bbl). But as soon as you build on the front facade, exceed the area limits, or deviate from the municipal environment plan, a permit is required.
Permit-free or permit-required: the boundary
The PlotSense Build Options Report calculates exactly how much you can build permit-free on your parcel. The core rules from the Bbl (art. 22.36) for the rear garden area are:
- Maximum 50% of the first 100 m² of rear garden area, 20% of 100–300 m², and 10% above that — up to an absolute maximum of 150 m².
- Extension depth maximum 4 metres, measured from the original rear facade.
- Height maximum 4 metres for an extension, 5 metres for a freestanding outbuilding.
- Minimum 1 metre distance from the plot boundary.
Exceeding these limits, or building on the front facade? Then an environmental permit for your extension is mandatory.
Step 1 — check the environment plan
Before applying for a permit, check whether your extension fits within your municipality's current environment plan (omgevingsplan). Since 1 January 2024, the environment plan replaced the land-use plan (bestemmingsplan) and contains local building rules. You can find it on ruimtelijkeplannen.nl or your municipality's website. Note: even if your extension falls within the national permit-free limits, the municipality may impose additional rules in the environment plan.
Step 2 — gather the required documents
For a complete permit application, you typically need:
- Floor plan and elevations — scale drawings (usually 1:100 or 1:50) with all dimensions.
- Location map — an extract from the cadastral map with your parcel marked.
- Construction description — a brief description of materials, colours, and structure.
- Boundary check — the measured distance from the planned extension to the plot boundary. The PlotSense Parcel Report includes a measurement map with these distances.
Step 3 — submit the application via the Environment Counter
You submit the permit application digitally via the Omgevingsloket online, the Dutch government's official portal for all environmental permits. You register an account, select your municipality, upload the documents, and describe the building plan. The system automatically determines which permits are relevant based on your input.
Step 4 — wait for the decision
The municipality typically has 8 weeks (regular procedure) or 2 to 6 weeks (short procedure) to issue a decision. For complex plans, the period may be extended by up to 6 weeks. You receive written notice of whether the permit is granted or refused. Approval may come with conditions, such as specific materials or colours.
What does an extension permit cost?
The fees (leges) charged by the municipality vary by municipality and depend on the complexity of your application. For an extension, this typically ranges from €150 to €500. Additional costs may include a building drawing (€300–€800 via an architect or drawing office) and possibly a structural calculation.
Common mistakes with extension permits
- Misjudging the plot boundary. Many owners assume the fence or hedge is the boundary, but the official cadastral line is often different. The PlotSense Parcel Report shows the exact cadastral boundary.
- Not checking the environment plan. Even permit-free structures must comply with local rules. Some municipalities, for example, require a specific roof tile.
- Incomplete documents. An application with missing drawings is not processed, leading to delays.
- Applying too late. Start the procedure before signing the contractor's contract — construction may only begin after the permit has become irrevocable.
How PlotSense helps with your extension permit
PlotSense gives you the facts you need for a smooth permit application:
- The Parcel Report (€25) shows the exact cadastral boundaries and a measurement map with the distance from each facade to the boundary.
- The Build Options Report (€65) calculates how much you can build permit-free and where the boundary lies between permit-free and permit-required.
This way, you avoid an incomplete application with the municipality — and prevent surprises down the line.