1. The funding framework that constrains costs
Social housing is not a building type, it is a funding route. A social block and a private one can be architecturally identical; what separates them is the financial structure, the rent ceilings and the obligations that flow from them.
- The deepest-subsidy product is intended for the most modest households, with very low income ceilings. It carries a heavily subsidised state-backed loan, central and local grants, and a reduced VAT rate of 5.5 %. Its rents are the most tightly controlled.
- The mainstream social product funds the majority of the social stock. It carries a preferential loan, VAT at 5.5 % and moderate rent ceilings.
- The intermediate product sits between social and private. VAT is 10 %, the rent ceilings are higher, and it targets middle-income households priced out of the private market.
The VAT advantage: the first lever
Reduced VAT at 5.5 % represents an advantage of 14.5 points over the 20 % applied to private housing. On a works budget of 2,000,000 € excluding VAT, that is a saving of 290,000 €.
The advantage is partial: it offsets the regulatory premiums on accessibility and energy performance, but does not by itself significantly reduce the overall cost of the operation. The real saving comes from the subsidised loan and the direct grants, not from the VAT differential alone.
2. Comparing the regimes on the key criteria
The table compares the four housing types on the determining economic and technical criteria. The ratios exclude parking and external works, in provincial values.
| Criterion | Deepest subsidy | Mainstream social | Intermediate | Private, sale or letting |
|---|---|---|---|---|
| Construction ratio excl. VAT, provincial | 1,680 – 1,990 €/m² floor area | 1,730 – 2,090 €/m² | 1,840 – 2,240 €/m² | 2,040 – 2,860 €/m² |
| Indicative rent ceiling | ~ 5.5 – 7 €/m²/month | ~ 6 – 8.5 €/m²/month | ~ 9 – 12 €/m²/month | Open market |
| Accessibility | 100 % of dwellings | 100 % of dwellings | 100 % of dwellings | 20 % minimum |
| Average dwelling area | One-bed 43 m², three-bed 78 m² | One-bed 44 m², three-bed 80 m² | One-bed 45 m², three-bed 82 m² | One-bed 42–55 m², three-bed 80–100 m² |
| Finishes | Functional standard | Functional standard | Slightly enhanced standard | Variable by developer |
| Energy performance | Current regulations mandatory | Current regulations mandatory | Current regulations mandatory | Current regulations mandatory |
| Construction support | VAT 5.5 % plus grants | VAT 5.5 % plus subsidised loan | VAT 10 % | VAT 20 % |
| Gap against private, construction cost | − 10 to 20 % | − 5 to 15 % | − 5 to 10 % | The reference |
The table reveals the essential point: the construction cost gap between social and standard private housing is only 5 to 15 %. The social landlord's principal saving does not come from the construction cost but from subsidised funding. The rent ceilings, on the other hand, constrain the technical choices and impose rigorous optimisation item by item.
3. Universal accessibility: the most structuring premium
The most significant technical difference between social and private housing is accessibility. In social housing 100 % of dwellings must be accessible to people with reduced mobility from the street onward, lift, routes, bathroom, doors. In private housing only 20 % of dwellings carry that obligation.
| Requirement, at 100 % of dwellings | Premium per dwelling | Share of the dwelling cost | What changes in practice |
|---|---|---|---|
| Lift from the first floor, against the third in private | 3,000 – 6,000 € | + 2 to 4 % | A smaller lift, but mandatory even at two storeys |
| Corridors at least 900 mm | 500 – 1,500 € | + 0.3 to 1 % | Partitions redistributed, usable area lost |
| Accessible bathroom in the smaller units | 800 – 2,000 € | + 0.5 to 1.5 % | Level-access shower, 1,500 mm turning circle |
| 900 mm entrance door and accessible entryphone | 400 – 800 € | + 0.2 to 0.5 % | Motorisation possible, adapted signage |
| Accessible parking, at least 2 % of spaces | 2,000 – 5,000 € | + 1 to 3 % | Oversized spaces 3.30 m × 5 m |
| Accessible external routes | 500 – 1,500 € | + 0.3 to 1 % | Gradients below 5 %, tactile paving |
| TOTAL, UNIVERSAL ACCESSIBILITY | 7,200 – 16,800 € | + 4 to 11 % | On a 65 m² dwelling at 2,040 €/m² floor area |
That premium of 4 to 11 % is often poorly built into social housing budgets. The lift mandatory from the first floor, against the third in private housing, weighs most heavily on small programmes: on a three-storey block of 12 dwellings, the mandatory lift represents 8,000 to 15,000 € per dwelling.
4. Rent ceilings and their effect on technical choices
The social landlord must balance the operation over the long term with rents capped well below the open market. That creates a permanent optimisation constraint: reduce the construction cost to improve the balance of the operation, while maintaining the performance that will keep tenants' running costs, and therefore arrears, down.
That double constraint of controlled construction cost and low running costs leads to technical trade-offs specific to social housing.
| Technical choice | Option A, cheaper | Option B, better quality | Effect on tenants' costs | Preferred in social housing |
|---|---|---|---|---|
| Heating system | Individual electric | Communal heat pump or district heating | A costs more than B over 15 years | B, for rent plus charges |
| Façade insulation | Internal, cheaper | External, dearer | B performs far better | B, where grant funding is available |
| Joinery | Standard PVC double glazing | Aluminium triple glazing | A loses more heat in cold regions | B in the colder climate zones |
| Ventilation | Simple extract | Heat recovery | B is far better acoustically | B, often required by the regulations |
| Kitchen fittings | Unfitted | Fitted kitchenette | A differentiator for attractiveness | Kitchenette in the smaller units |
| Parking | Surface spaces | Semi-sunken parking | No effect on running costs | Surface, where the local plan allows |
The social landlord's logic is one of whole-life cost, not construction cost alone. A communal heat pump costs 20 % more to install than individual electric heating, but it reduces tenants' costs by 400 to 800 € a year. Over 30 years the equation is amply favourable to landlord and tenant alike.
5. What social housing really saves
On finishes
The principal real saving is in the finishing trades: 200 mm porcelain tiling rather than large format, standard matt paint rather than decorative render, white PVC joinery rather than lacquered aluminium. These choices represent a saving of 80 to 150 €/m² of habitable area against standard private housing, that is 8 to 12 % of the construction cost.
On common facilities
Common parts in social housing are functional rather than representational: a plain entrance hall, compliant cycle and bin stores, no premium lobby and no costly landscaped garden. That sobriety represents a saving of 30 to 80 €/m² of floor area according to the standing of the private benchmark.
On parking
Social housing often benefits from planning relaxations allowing fewer parking spaces, justified by the lower rate of car ownership among its tenants. Each basement space avoided represents 28,000 to 40,000 €. On a 40-dwelling programme at half a space per dwelling instead of one, the saving is 560,000 to 800,000 €.
6. The economist's role on a social housing programme
The construction economist plays a specific role here: they produce the estimate for the operation but also the appraisal the landlord must present to its funders. That appraisal takes in the construction cost, the land, the fees, the financing costs and the rental income discounted over the loan's covenanted term, generally 40 to 50 years.
In social housing the economist is often consulted ahead of the planning application, to confirm the financial feasibility of the operation and identify the optimisation levers before the drawings are frozen.
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In summary
The construction cost gap between mainstream social housing and standard private housing is only 5 to 15 %, far from the received idea of social housing as intrinsically cheap. The landlord's principal saving comes from subsidised funding, the loan, reduced VAT, grants, not from the construction cost itself. In exchange, social housing carries additional constraints, chiefly universal accessibility at a premium of 4 to 11 %, which offset the savings on finishes. The optimisation logic is one of whole-life cost: invest more at construction to reduce tenants' running costs over 30 to 50 years.
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.
Sources: the BT construction cost indices published monthly by INSEE on its 2010 base, used to update the figures · construction cost statistics from SDES, the statistical service of the ministry responsible for construction · regulatory texts published in the Journal officiel and consolidated on Légifrance for the requirements cited.