Roof renovation in Brussels, Flanders and Wallonia

When should you renovate your roof?

Slipped tiles or slates, damp patches in the attic, a missing or damaged roofing membrane, persistent moss or cracked bitumen felt are all warning signs. The longer you wait, the more a small leak can damage the roof structure, insulation and ceilings, and the higher the bill.

A full renovation is also the right time to insulate from the outside, replace the zinc work and prepare for solar panels. Combining these jobs avoids putting up scaffolding twice and lowers the overall cost. It is also an opportunity to check roof ventilation and the condition of the gutters.

Pitched roof or flat roof

On a pitched roof, renovation generally involves removing the old covering, then fitting a breathable membrane, insulation, battens and the new tile or slate covering. External insulation, known as sarking, preserves the space under the roof and limits thermal bridges. The choice of material may also depend on the appearance required by your municipality.

A flat roof is renovated with a new waterproof layer, in EPDM or bitumen felt, laid on rigid insulation. The critical points are the edges, outlets and joints, where most leaks occur. A sufficient fall towards the outlets prevents standing water, which speeds up the ageing of the waterproofing.

Insulation, planning permission and grants

For a quality renovation, roof insulation generally targets a U-value of around 0.24 W/m²K or better, which means 15 to 22 cm of insulation depending on the material. Regional grants set their own performance requirements, which the contractor must meet. A properly fitted roofing membrane and vapour barrier ensure the whole build-up lasts.

Changing the appearance or volume of the roof may require planning permission: check with your municipality. Grants depend on the region and your income; the adviser calculates them for you and checks the conditions before work begins. Some schemes require documents to be submitted before the quote is signed.