Refurbishment: which regulations apply, and from what threshold, 2026

The general principle of construction law is that standards do not apply retroactively: a building erected in accordance with the rules in force at its date of construction is not required to meet later new-build standards, unless a specific law expressly imposes it. In practice that means a building of 1975 need not meet the current thermal or environmental regulations, nor necessarily the current accessibility standards.

Several thresholds or situations can trigger the partial or total application of new-build standards:

Existing apartment buildings are not subject to the same obligations as new ones. The accessibility order provides lighter requirements for works in existing housing: when substantial works are carried out — façade renovation, refurbishment of the common parts — certain improvements are required on that occasion. Those obligations concern mainly the external routes, the communal rooms and access to the letterboxes, according to a list set by order.

Existing buildings open to the public that do not comply with the accessibility standards may use a scheduled accessibility programme. Created in 2014 to replace the earlier statutory deadline, it allows compliance works to be spread over three, six or nine years according to the category. The programme is approved by the prefect and monitored through mandatory progress reports.

In refurbishment, derogations from certain accessibility obligations are allowed where there is a technical impossibility arising from the existing fabric: load-bearing walls, insufficient ceiling height, disproportionate cost. They must be sought and justified when the planning application or prior declaration is filed. The accessibility sub-commission examines those requests.

In refurbishment without a change of use, the principle is that existing installations complying with the rules in force at the date they were built are retained. A floor built in 1970 with a fire resistance of 30 minutes under the standard of the day need not be strengthened to REI 60 unless the works involve removing or rebuilding it.

Certain modifications trigger the current standards: complete replacement of a façade, bringing in the rule on vertical fire spread and the Euroclass system; creation of a new escape route, sized and protected to current standards; replacement of the fire safety system, requiring category A where the building has sleeping accommodation; and modification of the horizontal circulation, bringing in the current escape widths.

As noted in the hotel article, the hotel articles of the public-building regulation include provisions applicable to existing hotels even without works. That is the notable exception: in most buildings open to the public, safety requirements apply to existing buildings only on the occasion of works or of a commission visit.

The environmental regulations are strictly reserved to new buildings. They do not apply to renovation, whatever its scale. For renovation, the thermal regulation for existing buildings applies, alongside the commercial energy decree for the commercial stock.

ℹ A frequent confusion: the existing-buildings regime is not the environmental regulations The existing-buildings regime imposes minimum performance for each component replaced — insulation, windows, boiler. It imposes no bioclimatic calculation, no life-cycle assessment and no construction carbon indicator. The commercial energy decree imposes a reduction in energy consumption across the existing commercial stock, unconnected to the environmental regulations. A low-energy renovation label is a voluntary certification, not a legal obligation.

Permission is required in refurbishment for: creating floor area above 20 m² through extension or a roof extension; a change of use of the building or part of it; works modifying the load-bearing structure or the façade with a change of external appearance in a local plan zone; and any work on a building in a protected sector.

Change of use is one of the most heavily regulated operations in refurbishment. It corresponds to moving from one use class to another under the planning code — housing, activities, facilities, retail, commercial. Every change triggers the partial or total application of the standards of the new use, notably for thermal performance and accessibility.

Any serious refurbishment must rest on technical surveys that govern feasibility and budget:

ℹ ✔ Summary for the economist Heavy refurbishment of apartments: 800 – 1,500 € excl. VAT per m² of floor area, according to scale and initial condition. Light refurbishment, finishing trades only: 400 – 800 € excl. VAT per m². Asbestos premium: + 10 to 30 % on the demolition and strip-out cost where asbestos is present. Prior surveys: allow 5,000 – 20,000 € excl. VAT according to the size of the building. A change of use triggers accessibility obligations and sometimes a fresh thermal calculation. Never price a refurbishment without a pre-works asbestos survey: the risk of budget slippage is major.

Accessibility in existing public buildings and the scheduled programme are treated in detail in their own article. The thermal regulation for existing buildings is mentioned in the environmental regulations article, with the new-build and existing distinction clarified. The planning article details when permission is required in refurbishment. For existing hotels, the hotel article covers the provisions applicable without works.

ℹ The construction economist on demand. Refurbishing a building or changing its use? Quostra assesses the regulatory obligations triggered and prices the operation on the right assumptions.

Sources: the construction and housing code; the existing-buildings thermal orders of 3 May 2007 and 22 March 2017; the commercial energy decree of 2019; the planning code; and the accessibility ordinance of 26 September 2014.