New individual houses: standards and obligations 2026

An individual house is defined in the construction code as a residential building containing no more than two dwellings one above another, of which at least one is the client's principal residence or is intended for letting. It falls in the first regulatory fire family and is not subject to mandatory technical control, unless the site sits in a seismic zone of the third class or above, or particular risks are identified.

An architect is mandatory as soon as the floor area of the project exceeds 150 m². Below that threshold the client may file the application themselves or instruct an engineer or a package house builder. For a grouped-house operation carried out by a developer, an architect is almost always necessary, both for architectural quality and to manage complex local plans.

ℹ The thresholds in summary At or below 150 m² of floor area: direct client management is possible, no architect required. Above 150 m²: an architect is mandatory. In agricultural zones the threshold is 800 m². The statutory house-building contract provides a protective legal framework, with guarantees on delivery, completion and structural damage.

Any house whose floor area or footprint exceeds 20 m² requires planning permission. Below that a prior declaration suffices, except in a protected area. The statutory determination period is two months for an individual house, against three for other buildings. It is extended where a heritage easement applies: one month more where the opinion is advisory, three where it is binding.

The local plan fixes for each zone the set-back from boundaries — often at least 3 m laterally — the maximum height, often two storeys with a converted roof in suburban areas, the site coverage and the requirements on external appearance: roof pitch, materials. The abolition of site coverage coefficients in 2014 opened the possibility of densifying suburban plots, which sometimes conflicts with the prospect rules. In a heritage area, material requirements — natural slate, local stone, timber joinery — can weigh significantly on the budget.

Detached houses, in the first regulatory family, are subject only to minimum fire safety obligations. Terraced and grouped houses, however, are subject to compartmentation and separation rules. The best-known obligation is the autonomous smoke alarm, required in every dwelling since 8 March 2015.

For semi-detached and terraced houses forming a group, the regulation requires party walls separating two dwellings to achieve at least REI 60. The roofs of such groups must be subdivided by fire-stopping bands, or the houses must have separate roof profiles. A fire band projecting 0.15 m above the upper level of the roof removes the need for a discontinuity in the covering.

Accessibility regulation does not apply to a house built by its owner-occupier for their own account. As soon as the house is intended to be let or sold to a third party, however, it falls under the adaptable dwelling regime set by the order of 24 December 2015. That regime requires the dwelling to be designed so that it can later be adapted to a disability through simple works, without modifying structural elements.

ℹ The adaptable dwelling: minimum requirements → A functional horizontal route at least 0.90 m wide between walls, or between wall and obstacle. → The principal route within the dwelling — bedroom, WC, shower or bath — reachable in a wheelchair. → The WC: a manoeuvring space 1.50 m in diameter outside the door swing, or a lateral space of at least 0.80 m. → Provision in the bathroom ceiling so grab rails can be fitted later without heavy work. → Doors 0.80 m wide, giving at least 0.77 m clear, to bedroom, WC and bathroom.

The environmental regulations came into force for individual houses on 1 January 2022. Their thresholds are more demanding than for apartment buildings, because houses have a less favourable ratio of surface to volume. Gas heating has been prohibited in new houses since 1 January 2022, which produced an almost total switch to air-source heat pumps.

In practice a standard compliant house now systematically includes an air-to-water heat pump, high-performance insulation — a thermal resistance of at least 7 m²·K/W in the roof and 4 in the walls — triple glazing in the coldest zone, and high-efficiency heat-recovery ventilation. A green flat roof or photovoltaic panels improve the carbon balance without significant structural impact.

ℹ Traps to avoid An air-to-air heat pump alone is non-compliant if the installed capacity is insufficient, since domestic hot water must also be decarbonised. Thermal bridging at the slab-to-wall junction is frequent in traditional construction; specify thermal break units. A timber roof without a vapour control layer risks condensation and a loss of thermal performance over time. On construction carbon, standard poured concrete is penalised: consider timber frame, low-carbon concrete or lightweight blockwork.

The economist works mainly on individual houses in a development context — estates, grouped houses, planned development zones. The cost of a new house varies widely with the construction standard, the location and the level of finish. The figures below exclude land, estate infrastructure and fees.

ℹ ✔ Summary for the economist All-trades construction cost, excluding land, infrastructure and fees: 1,330 – 2,040 €/m² of floor area according to standing. Premium of the environmental regulations against the previous standard: an estimated + 3 to + 6 % for a house with a heat pump and heat-recovery ventilation. In a heritage area, allow a provision of + 10 to + 25 % on the façade and roof packages for the materials required. For a terrace of three or more, check the roof fire subdivision and the REI 60 party walls from the sketch stage. For an estate above 2,500 m² of floor area, a separate development consent is required alongside the house permissions: anticipate the extra time.

The environmental rules applicable to every new building type are developed in the environmental regulations article. Determination periods and floor area calculation are detailed in the planning article. Accessibility obligations are treated in full in the accessibility article. For houses in a heritage area, the planning article also develops the heritage opinion procedure and the material requirements. The refurbishment article covers existing houses subject to regulatory thermal renovation.

ℹ The construction economist on demand. Carrying out an individual or grouped-house operation and need an estimate at brief stage? Submit your file on quostra.com and an economist prices the environmental, accessibility, planning and fire impacts within hours.

Reference basis of the figures

The ratios per square metre and per item on this page are stated in January 2026 values. They were updated from January 2025 values, the basis adopted for the whole cocoon, using the BT01 all-trades index published monthly by INSEE on its 2010 base: 132.0 in January 2025, 134.7 in January 2026, a coefficient of 1.0205.

The global amounts quoted as examples, and any rents, charges or receipts expressed per year or per night, remain on their own basis: a building cost index does not apply to them.

To bring the ratios forward, apply the usual revision formula: updated value = page value × (BT01 for the month in question / 134.7). The BT01 measures contractors' input costs, labour at 44.9 % and materials at 36.5 %, not the prices actually tendered.