Roof insulation in Auderghem
Good roof insulation is the difference between a house that holds its heat in winter and cools naturally in summer, and a house where the heating runs constantly with no result. For owners in Auderghem and the surrounding communes, it's often the project with the biggest impact on the energy bill, especially in the townhouses and villas of the 50s-80s that have never been insulated from above. We install roof insulation, internal or external depending on the configuration, with a 10-year workmanship guarantee.
What does this insulation work involve?
There are two main ways to insulate a roof, depending on whether the attic is habitable or not.
Internal insulation (under the roof or on the attic floor): we fit panels or blown insulation between and under the rafters, or directly on the attic floor if it isn't converted. This is the cheapest solution. It suits cases where the covering isn't being renovated at the same time.
External roof insulation (sarking): we fit a rigid insulation panel on top of the structure before re-laying the covering. The thermal result is better because thermal bridges are eliminated. It's the reference solution when the covering is redone at the same time, because you don't pay the access work twice.
Flat roof insulation: on extensions or flat roofs, insulation generally goes on the outside, under the waterproofing membrane.
We choose with you the technique suited to your roof, your attic and your budget.
When should you insulate your roof?
The most frequent situations we see in Auderghem:
- The house is cold in winter even with the heating on full, particularly on the top floor
- In summer, the rooms under the roof become unbearable from June onwards
- Your house dates from the 60s-80s and has never had insulation work
- You're redoing the covering: it's the best moment to insulate externally without doubling the scaffolding costs
- You see condensation on the attic walls or damp rings on the top-floor ceiling
Why the roofs of Auderghem are often poorly insulated
Most houses built before 1980 in Belgium had no serious insulation standards. The villas and townhouses of Auderghem often have unconverted attics with little or no insulation, or thin glass wool laid in the 80s that has settled and lost half its performance.
More recent constructions can also be a problem if the work was badly done: untreated thermal bridges, badly fitted vapour barrier, insufficient thickness. We see houses from the 2000s losing as much heat as pre-war houses.
What makes the price of roof insulation vary
Roof insulation in Brussels has no standard price. What changes from one job to another:
- The chosen technique (internal, external, blown): big differences in labour and material costs
- The surface to insulate: a top-floor flat and a detached villa are very different
- The state of the structure and the existing underlay: if it has to be redone, that's an extra cost
- Attic access and the complexity of the shape (dormers, multiple angles)
- The insulation thickness fitted: the more you insulate, the less you heat, but there's a profitability threshold to calculate
- Combining with a covering renovation: external insulation costs far less combined than as a separate project
See also: Roof renovation · Flat roof & EPDM
Frequently asked questions
Can I get grants for roof insulation in Brussels?
Yes. In the Brussels-Capital Region, the Renolution grants cover roof insulation under certain conditions (minimum thermal performance, registered contractor). The amount varies with your income and the type of work. Call us: we explain what you're entitled to before starting.
Is it better to insulate from the inside or the outside?
If you're redoing the covering at the same time, external (sarking) without hesitation: better thermal result, no thermal bridges, attic volume preserved. If you're not opening the roof, internal is more accessible and cheaper. We tell you which suits your situation after a visit.
Does external insulation change the look of the roof?
No, if it's done well. We re-lay the same covering (slate, tile, zinc) over the insulation panel. From outside nothing changes except that the roof is slightly raised, which can require adapting the cornices and junctions. We handle those details within the job.
Can a flat roof be insulated?
Yes. On a flat roof, insulation generally goes on top of the structure, under the EPDM or bituminous waterproofing membrane. It's also the right moment to redo the waterproofing if it's old.
We already had glass wool fitted in the 80s. Does it need replacing?
Not necessarily removing, but often topping up. The glass wool of that era was laid at 5-8 cm, which no longer matches current standards. In some cases we can lay a second layer on top. We check the state during the visit.