Planning
Planning permission for your windows in Watermael-Boitsfort
It all comes down to three questions: where the house is, what changes, and whether it can be seen from the street. Here is what the commune (the local council), the Brussels Region and Homegrade say, with links so you can check for yourself.
Three questions about your house. Each answer is explained just below.
Is your house in Le Logis or Floréal?
Both garden cities are listed. The rules there are not the same as in the rest of the commune.
Will the windows look different?
A different material, wood to PVC for example, the glass divided up differently, or a different colour.
Can these windows be seen from the street?
Front façade, gable or dormer you can see from the pavement: yes. Rear façade hidden by the house: no.
The Logis-Floréal management plan decides
A heritage management plan has covered both garden cities since 1 September 2014. The works it describes, external joinery included, are exempt from authorisation. Anything that departs from it needs a permit. It describes painted timber joinery, a colour palette for each neighbourhood and two kinds of thin glazing.
Changing the look means a permit
The commune puts it in black and white: a permit is needed as soon as the appearance changes, whether that is the material, the division or the colour. Replacing white wood with white PVC needs one too. Useful to know: for windows, the application is exempt from the file fee and the municipal tax.
Like for like, with conditions
In a house that is not protected, a like-for-like replacement can be exempt from planning permission if the visible divisions, the opening sashes and the fixed frames stay the same. The exemption falls away when the project departs from a planning regulation or a special land-use plan (PPAS), and the commune has several. A word with its planning department beforehand clears up any doubt.
Like for like, on the garden side
The commune lists the replacement of windows visible from public spaces among the works that need a permit. On the garden side, with no change in appearance, you are in the lightest position. Special land-use plans in some neighbourhoods still have their say, so a question to the planning department before you order remains a good habit.
A guide, not an official opinion. Sources: commune of Watermael-Boitsfort, Homegrade, urban.brussels. Checked on 15 September 2026.
What the commune says
Two pages, two wordings
On its page about replacing windows, Watermael-Boitsfort presents replacement as work that requires a permit, and advises always giving wood priority. A whole paragraph, headed “Why not PVC?”, sets out its reservations: chlorine, dioxins, additives.
Its page on planning permission is more precise. There, a permit is required if the appearance is modified, and the commune spells out what it means by that: the material, the division, the colour. The list of works concerned also includes replacing windows and doors visible from public spaces.
The two texts do not really contradict each other, but they do not say the same thing with the same force. For a particular house, the safest course is still to ask the planning department, which handles enquiries, planning information and advice. The commune says so itself: a simple contact beforehand avoids a lot of trouble.
What the Region says
When a house that is not protected is exempt
The Brussels Region provides for what it calls minor works, which are exempt from planning permission. Homegrade, the Brussels renovation advice centre, sums up the conditions for windows: a replacement can be exempt if the visible divisions, the opening parts and the fixed frames are kept.
Two limits matter. Replacing white wood with white PVC still needs a permit, even if the colour stays the same, because the material changes. And the exemption no longer applies as soon as the project departs from the Brussels regional planning regulation (RRU), a municipal planning regulation or a special land-use plan (PPAS).
This exemption covers properties that are not protected. In Le Logis and Floréal, which are listed, a different regime applies.
At a glance
Your situation, and what to expect
A table to help you find your case. It sums up the texts quoted above, without replacing them.
| Your project | What applies |
|---|---|
| Same material, same divisions, same colour, house not protected | Exemption possible, if no regulation or special plan stands in the way |
| Wood replaced with PVC or aluminium | Permit, the material changes |
| Glazing divisions changed, glazing bars removed for example | Permit, the division changes |
| New window colour | Permit, the colour changes |
| House in Le Logis or Floréal | Heritage management plan, and a permit for anything that departs from it |
Some neighbourhoods
Where a special plan has a say
The commune publishes the list of its special land-use plans. If your street is in one of them, that plan sets some of the rules, and a regional exemption may no longer apply.
- Souverain-Est and Souverain-Ouest
- Coin du Balai
- Étangs de Boitsfort
- Plateau Boitsfort
- Wiener
- Vallée de la Héronnière
- Archiducs
Areas of cultural interest
Aluminium, sometimes held back
The commune also has areas of cultural, historical or aesthetic interest. In May 2024, on the subject of a garage door on boulevard du Souverain, its consultation committee recommended keeping the use of aluminium to limited cases.
This is not a general ban. It is a sign that on a visible façade, in these areas, an aluminium project will be looked at closely.
The two garden cities also have their own zoned municipal planning regulation.
In practice
The permit application, step by step
For windows, there is no need to write a novel. What matters most is being organised, and not ordering anything too early.
- Photograph what is there nowThe whole façade, then each window concerned, face on. That way the current divisions and fixed frames can be seen.
- Describe the new windowsMaterial, divisions, colour, opening sashes. A detailed quote already contains most of this description.
- Contact the planning departmentBefore you submit anything. That is where you find out whether the street falls under a special plan.
- Submit the applicationFor windows, the commune exempts it from the file fee and the municipal tax. Homegrade helps free of charge to put together an application without an architect.
- Order after the decisionMade-to-measure windows cannot be resold. Better to wait for the green light than to have to redo everything.
Frequently asked questions
Permits and windows, the questions that keep coming up
Does a permit application for windows cost anything?
Not in administrative fees. For windows, the commune of Watermael-Boitsfort exempts the application from the file fee and the municipal tax.
Should I wait for the permit before ordering?
Yes, that is the most prudent course. Made-to-measure windows cannot be resold, and a refusal would mean reworking the project after the fact.
What exactly does like-for-like replacement mean?
Keeping the visible divisions, the opening parts and the fixed frames, in the same material and the same colour. That is the condition Homegrade gives for a replacement to be exempt from planning permission in a house that is not protected.
Who can help me prepare the application for free?
Homegrade, the Brussels Region’s advice centre, supports permit applications without an architect free of charge. The commune’s planning department, for its part, handles enquiries, planning information and advice.
My house is in Le Logis or Floréal, so what changes?
Both garden cities are listed. The works described in their heritage management plan, in force since 1 September 2014, are exempt from authorisation. Anything that departs from it needs a permit. The details are on our page about the two garden cities.
Sources consulted on 15 September 2026: commune of Watermael-Boitsfort, replacing windows, planning permission and special land-use plans (in French); Homegrade, works without a permit for properties that are not protected; urban.brussels, municipal planning regulations; opinion of the consultation committee of 14 May 2024 (in French).
Unsure about your façade?
Send us a photo of the façade and tell us what you want to change. We will tell you what we see, and who to turn to if the answer is for the commune to give.
Did a rule change at the commune, or do you see a mistake on this page? Let us know and we will fix it.