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Energy roof

Roof insulation and energy renovation

An energy roof is a roof replacement with a continuous layer of above-rafter insulation and an airtight vapour control layer built into it, sized against the thermal requirement in force at the property address. The only sane time to do it is while the roof is already open. Insulating from inside the loft costs less on the day and costs more over twenty years: you lose headroom, you fight every penetration, and you inherit whatever condensation risk the old build-up already had. When the covering is off anyway, above-rafter insulation is the correct engineering answer — a continuous layer with no thermal bridge at every rafter, and a vapour control layer that is actually continuous because it was installed on an open deck.

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What's included

Published benchmark

€20–90 / m² as a separate line

Slovenian guides put insulation around €10–30/m², Austrian ones around €20–60/m², and Italian ones around €50–90/m² — the spread reflects layer thickness and detailing far more than national labour rates. Always compare thickness and lambda value, never headline price.

  • U-value calculation for the proposed build-up against the applicable national requirement
  • Condensation risk assessment for the finished construction
  • Continuous above-rafter insulation board, taped and sealed
  • Airtight vapour control layer with taped laps and sealed penetrations
  • Thermal bridge detailing at eaves, verge, ridge and every abutment
  • Ventilation path maintained above the insulation where the build-up requires it
  • Between-rafter or loft-floor insulation where above-rafter is not viable
  • Documentation pack for national energy schemes and tax relief claims
  • Thermographic verification photographs after completion, on request

We calculate the build-up; we do not pick a thickness

There is no such thing as a correct national insulation thickness. The right answer depends on the rafter depth you already have, the covering you are putting back, the climate zone and the requirement in force at your address. In Austria that requirement arrives through the OIB directive as adopted by your Bundesland and can differ across a provincial border. We calculate the layer and show you the calculation.

  • Target U-value taken from the requirement applicable at the property address
  • Build-up modelled layer by layer, including fixings and their thermal effect
  • Interstitial condensation checked before the specification is issued

Airtightness is the part most contractors skip

An insulation layer with an interrupted vapour control layer behind it will underperform its calculation and can wet the structure it is protecting. The tape, the grommets around every cable and pipe, the junction at the wall head — that detailing is where the performance actually lives. It is slow, it is unglamorous, and we photograph all of it.

The paperwork has real financial value

In Italy, qualifying work on a main residence carries a 50% deduction in 2026 against a maximum eligible spend of €96,000 per unit, and the classification of the works decides whether your job qualifies. That classification is a documentation exercise, and getting it wrong is expensive. We produce the technical pack; your accountant files it.

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See all questions

Can we stay in the house during the work?

Almost always, yes. The roof is opened and closed in sections so the building is weathertight every evening, and interior access is only needed where we are working inside the loft. It is noisy, there is a scaffold outside your windows, and there will be dust in the loft — but you will not need to move out. Flat roof works over a habitable room are the usual exception, and we tell you in advance if yours is one.

Does Italian tax relief apply to my roof?

It depends on how the work is classified, and the answer surprises people. Replacing a covering with the same materials, swapping damaged tiles and renewing waterproofing all count as ordinary maintenance, which on a single dwelling is not deductible — it is deductible only on the common parts of a condominio. The relief applies when the roof forms part of a wider extraordinary maintenance or renovation, because the higher category absorbs the lower. Where it does apply, 2026 gives 50% on a main residence and 36% otherwise, over ten instalments, capped at €96,000 of spend per unit, with a further total ceiling for higher incomes. That classification is a technical exercise the roofer has to get right. We produce the technical pack; your accountant or tax adviser files it. We do not give tax advice and you should not take any from a roofing company.

How thick should my roof insulation be?

There is no correct national answer, and anyone who gives you one without a calculation is guessing. The right layer depends on your rafter depth, the covering going back on, the climate at your address and the requirement legally in force there — which in Austria can differ across a provincial border because each Bundesland adopts the OIB directives in its own version. We calculate the build-up against the applicable requirement and show you the calculation.

Can insulating my roof cause condensation problems?

Badly detailed insulation absolutely can — and it is one of the most common ways a well-intentioned energy upgrade damages a building. Warm moist air reaching a cold surface inside the construction condenses there, and if the vapour control layer is interrupted at every cable and pipe, that is where it happens. We run an interstitial condensation assessment before issuing the specification, and the airtightness detailing is priced as a real line item rather than assumed.

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Start with the survey. Decide after you have read it.

A fixed-fee survey, a written condition report with annotated photographs, a realistic remaining service life and a costed action list. Credited in full against your project if you go ahead — and still useful if you do not.

Book a roof survey Or see the packages first

Water coming in right now? Mark the enquiry urgent or write to hello@roofpruf.com, and stay off the roof — do what is safe from inside while we read it.