What does attic-floor insulation cost in 2026?

That depends heavily on the measure. Insulating the attic floor costs on average € 1,000 to € 2,500 for an average home and is the fastest, cheapest option for an unused attic. Insulating the sloped roof from the inside costs € 2,500 to € 8,000 per job (roughly € 50 to € 100 per m²), including the finish. Insulating a flat roof from the inside comes to € 1,500 to € 5,000 per job (roughly € 40 to € 90 per m²). An insulation survey with thermal scan costs € 95 to € 250.

That depends on what you do with the attic. If you use it only for storage, insulating the attic floor is almost always the smartest choice: cheap, fast and without a finish, because the heat need go no further than the lived-in floor below. If you want to use the attic as a room, you insulate the roof slope itself, so it stays comfortable up there too. If you are unsure, an insulation survey with thermal scan reveals it.

No. This site focuses on insulating from the INSIDE: the attic floor, the roof slope from the inside and a flat roof via the underroof, with the roof covering intact. Exterior insulation — tiles off, insulation underneath and a new roof covering — is a roofer's job; for that you work with a specialised roofing company.

No. This site is about the roof and attic. Cavity-wall insulation (the facade), floor insulation and crawl-space (ground) insulation belong to specialised companies for the shell beneath and around the home — a different trade from roof insulation.

Yes. Insulation works both ways: the same layer that keeps heat in during winter keeps heat out in summer. If you use the attic as a room, insulating the roof slope makes it noticeably cooler on hot days. Also think about ventilation, so warm air can escape at night.

Insulating the attic floor is usually done in a day and causes little disruption — the insulation is laid on the floor. Insulating the roof slope with a finish is more work: it involves working against the roof surfaces and finishing with board or plasterboard, so expect a few days and some building dust. Everything happens indoors; no scaffolding is needed.

There is no single best material for every situation: insulation boards, mineral wool and blown-in or sprayed material each have their own price, insulation value and application. Which one fits depends on the roof type, the available thickness and whether you finish it or not — the installer assesses that on site. Ask each quote for a short justification of the material and thickness choice, so you can compare them fairly.

Yes, that matters. The better the roof insulates, the less the air refreshes by itself. Make sure humid air keeps a way out — through ventilation grilles, a tilting roof window or mechanical extraction — so no condensation forms between the insulation and the roof. A proper company already accounts for that in the plan.

Yes, a national insulation subsidy exists (the ISDE scheme). The conditions and amounts change regularly, so we deliberately quote no figures here — ask the installer about the current scheme and have the quote name which measures qualify.

Yes. Submitting a request costs nothing and commits you to nothing. You receive up to 3 quotes and choose yourself — or no one, that's fine too. Prices and payment are arranged directly with the insulation company.

Insulation companies in your region respond as soon as possible with a price indication. In autumn, before the heating season, diaries are fullest — whoever places a request well in advance compares calmly and schedules the work at the preferred moment.

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