The four components
| Component | Nature |
|---|---|
| Carrying cost | finance and fixed costs during processing |
| Mandatory studies | imposed by region and type of works |
| Fees relating to the application | preparation, lodging, procedural follow-up |
| Taxes and charges | set at municipal level |
The last three can be priced. The first is borne, and it is nonetheless what widens the gap between regions.
The period is the principal component
Differences between regions are considerable and all run from a complete file. The time needed to make the file complete comes on top of those periods.
| Region | Consent period |
|---|---|
| Flanders | 60 days simplified, 105 days ordinary procedure |
| Wallonia | 75 to 115 days depending on procedure |
| Brussels-Capital | 160 days |
Between a simplified Flemish procedure and a Brussels procedure, the gap exceeds three months. On a financed project that represents interest during construction, prolonged professional fees and greater exposure to price movement.
Two important qualifications.
The period runs from a complete file, which is not the date of submission. In practice several further months elapse between the two.
The ordinary procedure involves steps that lengthen the programme, notably public enquiry and the consultation committee, which are more frequent and longer in Brussels.
Mandatory studies vary by region and by project
They cannot be inferred from one region to another. Each region sets its own amounts and its own exemptions.
Everywhere, an architect is mandatory for works requiring consent, and an energy performance officer is involved on most projects.
In Flanders, a monitoring plan is mandatory for demolition above a certain volume, which forms a specific study item.
Everywhere depending on the case, topographical survey, ground investigation, pre-demolition surveys and, depending on the nature of the project, impact assessments are added.
A study imposed in one region and not in another creates a cost gap appearing in no construction benchmark.
Taxes belong to the municipal level
This is the level most often omitted from budgets. It is the municipal taxes on permits.
Taxes and charges relating to the issue of a permit are set by municipalities and vary between them within a single region. They often depend on the nature and scale of the works.
The municipal planning department is the contact before budgeting, and a preliminary call also avoids procedural errors costing far more than the tax itself.
What exemptions change
A project exempt from consent is not thereby free of formality. A prior notification often remains required.
In Flanders, certain exempt works must nonetheless be notified to the municipality.
In Wallonia, the May 2025 reform of the territorial code widened the list of exempt works, which may change the regime applicable to a project compared with an earlier state of the law.
In Brussels, the basic rule remains wide: most construction, alteration or change-of-use works require consent.
Checking the applicable regime before concluding that an exemption applies is therefore indispensable, because the regional lists do not coincide. The check is made with the municipality concerned.
How to budget this phase
Four steps.
1. Identify the region and municipality, then consult the planning department.
2. List the studies imposed by the nature of the project and by the region.
3. Price the carrying cost on the basis of the regional period, increased by the time to make the file complete.
4. Provide for procedural risk, because a request for further information resets the clock.
That last point is the most underestimated. An incomplete file does not extend the period; it postpones its starting point.
This article reflects regulation at the date of checking and serves professional orientation. It does not constitute legal advice and does not replace assessment of the individual case.