Second fix and building services
Insulation in Belgium
Indicative prices, what to check on a quote and a page for each of the 30 cities, with the pros registered in the area. Describe your project once, then compare the quotes you receive side by side.
- Free for homeowners
- No commission on the works
Trade sheet
- Trade
- Insulation
- Group
- Second fix and building services
- Price guide
- €25 to €60/m²Roof insulation (interior)
- Prices surveyed
- July 2026
- City pages
- 30
What this trade covers
An insulation company treats the roof, the walls (cavity, inside or outside) and the floors to limit heat loss. The result depends as much on the fitting as on the insulation chosen.
Common jobs
- Roof insulation from inside
- Cavity wall injection
- Floor or cellar ceiling insulation
- Vapour barrier and airtightness
Insulation: indicative prices in 2026
Ranges surveyed in Belgium in July 2026. The real price is the one on the quote: the job, the materials and the access change everything.
- Roof insulation (interior)
- €25 to €60/m²
- Cavity wall insulation
- €20 to €30/m²
VAT
In a private home more than ten years old, most works invoiced by the contractor go down to 6% VAT instead of 21%. The invoice must carry the statement required for the reduced rate.
What to check on the quote
Two quotes only compare when they cover the same thing. These points often separate a complete offer from one that ends in extras.
The insulation and its performance
The quote names the material, the thickness and the R or lambda value. Compare at equal performance, not on price alone.
Vapour barrier and airtightness
Fitting the vapour barrier, the joints and the tapes is included. Sloppy work wipes out part of the gain.
The state of the base
Missing underlay, a damp or blocked cavity: preparatory work is priced separately rather than discovered mid-job.
Grant conditions
Before you sign, check what your region requires on the material, the contractor and the application.
The company number
The quote shows the company's CBE number. Check it on the public search of the Crossroads Bank for Enterprises before you sign.
VAT, deposit and validity
The quote states the VAT rate applied, any deposit and how long the price is guaranteed.
Insulation: choose your city
Each city page shows the registered pros whose address is in the area, and the regional renovation support.
Brussels-Capital Region
Your town is not on the list?
Search by postcode and radiusFurther reading
Detailed prices, VAT, checks before you sign: our full guides.
Budget & financing
Insulation prices in Belgium: roofs and cavity walls
5 min read
Energy & insulation
Roof insulation: glass wool, PIR or cellulose?
5 min read
Legislation & grants
6% VAT in Belgium: conditions, invoice wording, pitfalls
9 min read
Legislation & grants
Vetting a tradesperson before you sign: the CBE checklist
4 min read
Frequently asked questions
Insulation: what budget should you plan in 2026?
As a guide in Belgium in 2026: Roof insulation (interior): €25 to €60/m²; Cavity wall insulation: €20 to €30/m². The final price depends on the job, the materials and the access: compare several written quotes.
Where should you start: roof or walls?
The roof, in most houses: heat rises, and an uninsulated roof is often the biggest source of loss. Cavity walls come next, when the house allows it.
Do you need ventilation after insulating?
Yes. A better insulated house becomes more airtight, and without proper ventilation condensation sets in. Plan insulation and ventilation together.
Which VAT rate applies?
In a private home more than ten years old, most works invoiced by the contractor go down to 6% VAT instead of 21%. The invoice must carry the statement required for the reduced rate.
How do you check a contractor before signing?
Check their company number at the Crossroads Bank for Enterprises, ask for a detailed written quote with VAT, and read the reviews. On Batizzy, the "CBE verified" badge marks pros who had their number checked, and a review is only possible after a real job.
How do you get quotes you can compare?
Describe your project once on Batizzy, with a few photos. Pros see the jobs in their area first and send you their quote, which you compare side by side. It is free for homeowners, and Batizzy takes no commission on the works.
A project coming up?
Describe it once, it is free. Pros from your area answer with a quote in the same format, and you decide what happens next.