Apartment building construction costs: ratios per m², types and specification levels

Before any ratio, the area it applies to must be clear. In apartment building three areas coexist and are regularly confused, generating major budget misunderstandings.

• Regulated floor area is the statutory and fiscal area, measured to the internal face of the façades. It is the area used for planning and for construction ratios. It includes common circulation, plant rooms and risers.
• Habitable area is the net area of each dwelling after deducting walls, partitions, stairs, risers and openings. It is always smaller than floor area, generally in a ratio of 0.78 to 0.85 according to the compactness of the programme.
• The former net area is an intermediate measure obsolete since 2012, replaced by regulated floor area, but still found in some older databases.

Converting between the two

To go from a ratio per square metre of floor area to one per square metre of habitable area, divide by the programme's habitable-to-floor coefficient. That coefficient is typically 0.80 to 0.85 for standard apartments.

For example: 2,200 €/m² of floor area ÷ 0.82 = 2,683 €/m² of habitable area. That is 483 €/m² of difference, on a programme of 2,000 m² habitable, 966,000 € on the envelope.

Always state the reference area before comparing ratios.

The ratios below exclude parking, external works and fees. They include structure, finishing trades, technical packages, finishes, lifts, common parts, safety equipment and a 6 % contingency.

Apply the regional factor for your area, set out in the pillar article of this cocoon. In the Paris region, multiply by 1.15 to 1.30.

Social housing is not necessarily cheaper to build

Social programmes benefit from standardised areas and economical finishes, but they carry full universal accessibility, every dwelling accessible under the current regulations, reinforced acoustic standards and sometimes thermal performance requirements above what the private sector would impose.

The cost gap between social and standard private housing is often only 5 to 10 %, not the 20 to 30 % often imagined. The real difference lies in the finishes and the equipment, not in the structure.

The number of storeys is one of the least well anticipated parameters in apartment budgets. Intuition says that the higher you build, the more you amortise the structure and the land, true in property terms, but only partly true in construction cost.

From a pure construction cost standpoint the optimum band lies between four and seven storeys: the lift is amortised across all the dwellings, the structure repeats, and the high-rise thresholds are not reached. Above eight storeys, each additional level generates rising structural and regulatory premiums, justified only by the value of the land saved.

Parking is the item most often under-estimated in preliminary apartment budgets. The local plan imposes a number of spaces per dwelling, generally one to one and a half in dense urban areas, and the nature of the parking, surface, deck, semi-sunken, basement, is rarely negotiable when the site is constrained.

* Percentage calculated on a 40-dwelling programme. The relative effect falls slightly on larger programmes.

On a 40-dwelling programme in a regional city with one basement space per dwelling, parking alone represents 1,120,000 to 1,600,000 €, that is 12 to 15 % of the total construction cost. It is the first item to assess precisely in any dense-area apartment budget.

For a standard apartment programme, seven storeys, one parking level, standard private specification, the typical budget distribution is as follows.

• Structure: 28 to 33 %. Foundations, reinforced concrete structure, floors, stairs, masonry. The heaviest package and the one where savings are hardest without affecting structural quality.
• Façades and external joinery: 12 to 16 %. External or internal insulation, aluminium joinery, roof waterproofing. Strongly affected by the current thermal regulations.
• Mechanical services and plumbing: 10 to 14 %. Communal or individual heating, hot water generation, heat-recovery ventilation (increasingly frequent), sanitary services. The choice of system, heat pump, communal boiler, district heating, has a significant effect.
• Electrics and automation: 6 to 9 %. Distribution board, cabling, common lighting, entryphones, and provision for electric vehicle charging, mandatory in new build since 2021.
• Lifts: 3 to 5 %. From one lift at four storeys to two at eight and above, with accessibility compliance.
• Internal finishes and finishing trades: 18 to 24 %. Floor finishes, tiling, painting, internal joinery, sanitary fittings. This is where the specification level shows most visibly and can be calibrated most directly.
• Internal external works and landscaping: 6 to 9 %. Buried services within the site, fencing, private roads, landscaping, cycle store, bin store.

A compact building, rectangular, with a length-to-width ratio near 1, costs 5 to 10 % less per square metre than one in an L or a U, or with multiple set-backs. Every internal or external corner creates interfaces between trades, complicates the formwork, and increases the length of façade and roof. Architect and economist should assess the premium of each formal choice together.

Moving from individual electric heating, the cheapest to install and the dearest to run, to a communal water-source heat pump or a connection to district heating represents a premium of 800 to 1,500 € per dwelling at construction, often recovered in five to eight years on running costs. Ideally the economist builds that whole-life comparison into the outline analysis.

Where the local plan allows it, reducing the number of spaces or substituting surface for basement spaces is the most powerful budget lever available. Each basement space avoided recovers 28,000 to 40,000 €, the equivalent of 12 to 18 m² of additional dwelling at the same cost.

At outline stage the economist produces an estimate structured by trade, with the ratios adopted explained and the band documented. They flag the assumptions to be confirmed, the mechanical system, the final number of storeys, the type of parking, and price the variants if the brief is still open.

At developed design the measure details each package with real quantities taken off the drawings, market unit rates and package-by-package provisions. It is the basis of the tender package and the first document that can be set against the contractors when the offers are analysed.

You have better things to do. Submit your apartment project on quostra.com; outline estimate delivered within 72 working hours.

The cost of building apartments runs from 1,630 €/m² of floor area for standard social housing to more than 4,080 €/m² for high-end in a major city. Four parameters explain most of the spread: the specification level, the number of storeys with a critical threshold at the high-rise regime, the type of parking, the difference between surface and basement can be 15 % of the budget, and geography, a factor of 0.90 to 1.30 by area. A reliable estimate states the reference area clearly, documents the structuring assumptions and prices the variants still open.

Reference basis of the figures

These bands are orders of magnitude for framing, and their reference market is the Paris region. They serve to place a budget at the earliest stages and to compare building types with one another. They replace neither a tender exercise nor an estimate prepared on drawings, and they are not a record of prices actually charged.

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 rise of about 2 %.

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 index has kept rising since: it stood at 138,3 in June 2026, the last value published when this page was checked, that is 2,7 % above the reference base. BT01 measures contractors' input costs, wages and social charges, materials, plant and energy, not the prices actually tendered.