Check a joiner before you renovate
What to check before you pick a contractor for windows, doors and joinery, and what the region and the premiums ask.
18.760 active companies have windows, doors and joinery as their main activity.
KBO, enterprises whose main activity falls under 43.32, 43.343 · 12 November 2026 · All companies in Schrijnwerk
Professional competence
In Wallonia and Brussels, whoever does windows, doors and joinery needs the professional competence for joinery and glazing. Flanders has not required it since 2019.
Premiums
Flanders: the premium for windows and doors asks for a contractor, Belgian VAT on the invoice and the contractor’s certificate. Wallonia: access to the profession for joinery and glazing.
By municipality
What the premiums ask of the contractor
- Flanders
- Flanders (Mijn VerbouwPremie): most work only counts when a contractor does it. The invoice shows the contractor’s name, address and VAT number and Belgian VAT, and the contractor fills in a certificate with their enterprise number. No professional competence is required; a heat pump is installed by an installer with a RESCert certificate. The conditions
- Wallonia
- Wallonia (primes Habitation): the contractor is registered in the KBO and has access to the profession for the work: roofing and waterproofing for the roof, structural work for walls, joinery and glazing for windows, central heating, air conditioning, gas and sanitary for heating. An electric heat pump also needs electrotechnical activities. The conditions
- Brussels
- Brussels (Renolution): the contractor is registered in the KBO, VAT registered and has access to the profession where the work needs it. Invoices from 2025 and 2026 don’t qualify for a premium for now; the competence rule still applies. The conditions
For 6% VAT on renovation (a home over ten years old), a VAT-registered contractor invoices you directly.
Firmatlas gives no legal advice. Check your premium’s conditions before you sign.
What no register shows
- Ask for a written quote with name, address and enterprise number, and compare a few.
- Don’t pay a large deposit. Agree on payment in stages as the work progresses.
- Ask for the ten-year liability insurance certificate when the work needs an architect.
- Ask for references of work nearby and go and look.
- Check that the enterprise number on the quote is this company’s.
Questions about checking a contractor
What professional competence does windows, doors and joinery need?
In Wallonia and Brussels, whoever does windows, doors and joinery needs the professional competence for joinery and glazing. Flanders has not required it since 2019.
What does the premium for windows, doors and joinery ask of the contractor?
Flanders: the premium for windows and doors asks for a contractor, Belgian VAT on the invoice and the contractor’s certificate. Wallonia: access to the profession for joinery and glazing.
How do I check a joiner?
Look the company up above by name or enterprise number and enter the postcode of the work. You see whether it is active, whether its VAT number is active, whether it is not bankrupt and whether it holds the professional competence for the work.
By type of work: Roofer · Structural contractor · Plasterer · Tiler · Painter · Heating engineer and plumber · Electrician · Heat pump installer · Insulation company · General contractor · Demolition company