Do I need planning permission and an architect to put in a new window or roof window, or to remove a load-bearing wall?

What is not allowed, what is required?

• Flanders: façade and roof works that do not change the volume of the house (for example, a new window or a roof window set flush with the roof) do not need a permit. The energy performance must not get worse. Works that change the volume, such as a dormer (dakkapel), need a permit.
• Flanders: if the work involves load-bearing parts (stabiliteitswerken / travaux de stabilité), the exemption only applies if an architect designs and supervises the work. This rule also applies to interior renovations.
• Wallonia: putting windows in the roof surface does not need a permit if the windows are all at the same level and their total width is no more than a quarter of the length of the façade. On a façade that does not face the street, putting in windows or doors up to a quarter of the façade length does not need a permit, subject to conditions. Works that stay within a quarter but do not meet these conditions need a “limited impact” permit (permis d'impact limité); larger works need a standard permit.
• Brussels: interior renovation that does not involve the load-bearing structure does not need a permit. On a roof with a pitch of less than 45°, windows in the roof plane do not need a permit if they cover no more than 20% of the roof area. Putting a new window in a façade visible from the street needs a permit.
• In all regions: for a listed building or one on the heritage inventory, or where there is a municipal zoning plan or a subdivision permit, the exemption may not apply. Before you start, ask your municipality's planning department (dienst omgeving / service urbanisme).

Penalty and indirect consequences

Why does this rule exist?

If work on load-bearing walls and roofs is done badly, the building can collapse; the architect keeps this risk in check. Changes to a façade visible from the street affect the look of the street and the neighbours' privacy.