A dormer without a permit: when is it allowed?

A dormer gives you more space and light in the attic. But do you need a permit? The answer depends mainly on which side of the roof it goes on and a few measurements. These are the rules under the Dutch Environment and Planning Act (Omgevingswet).

Two sides to the question

For building work, the government looks at two things. The technical part is about safety and building quality. For a dormer that part is always permit-free, but it must still meet the building regulations. The spatial part is about how the dormer fits into its surroundings. That's where the difference lies.

At the back: often permit-free

Is the dormer going on the back roof, or on a side roof that doesn't face the street or a public area? Then it's permit-free under national rules if it meets all five of these requirements:

1. The dormer has a flat roof.
2. The dormer is no higher than 1.75 metres, measured from its base.
3. The bottom is more than 0.5 and less than 1 metre above the eaves.
4. The top is more than 0.5 metres below the ridge.
5. The sides are more than 0.5 metres from the sides of the roof.

At the front: the municipality decides

For the front roof, or a side roof that faces the street, your municipality's environmental plan (omgevingsplan) decides what's allowed. In many municipalities a dormer is permit-free there too, if it meets the same measurements, fits the plan's rules and the area has no aesthetic requirements. But municipalities may change this. So always check the environmental plan or ask the municipality.

Exceptions: listed buildings and protected townscapes

You almost always need a permit if:

• your home is a municipal, provincial or national monument, or directly attached to one;
• your home is in a nationally protected townscape and the dormer goes on a side roof or a back roof facing a public area.

You also can't build permit-free on a structure that was itself built without the required permit.

How to check it yourself

1. Go to the Omgevingsloket (the national permit portal) and do the permit check for "dakkapel".
2. Enter your address, the side of the roof and the measurements.
3. If a permit is needed, you can submit the application through the Omgevingsloket too.

Don't forget the neighbours. Neighbour law still applies, even if you don't need a permit. A short chat beforehand prevents a lot of hassle.

What we do

During the free site visit we measure the roof and check together whether the dormer can be permit-free. If a permit is needed, we supply the drawings and measurements for the application. See how it's done in 3D on our Dormer page.

Source: Informatiepunt Leefomgeving (IPLO), "Dakkapel" under the Omgevingswet (consulted October 2026). Rules may differ per municipality. This article is general information.