Non-Conforming Windows in VEFA at Nice: Actual Dimensions vs. Plans

EXPERTISE — VEFA (Vente en l’État Futur d’Achèvement, sale of future completion)

You have just taken delivery of your new apartment in Nice. You take out your tape measure and start checking. The living room window, specified to be 1.80 m wide on the VEFA plan, measures 1.74 m on the wall. A difference of 6 cm. This is not an impression: it is a non-conformity. On the scale of a real estate project, these cumulative discrepancies can represent several square meters less of glazed surface.

What You See — and What It Really Hides

The symptom is simple: the sliding door is smaller than expected. You compare the facade plan (scale 1/50) with your laser distance meter. The discrepancy is obvious.

What it hides is often a defect in the rough structure layout or a manufacturing error in the joinery. On a case in Nice last year, I measured a systematic discrepancy of 3 to 8 cm on all openings in a residence. The developer argued a “construction tolerance.” Frankly, tolerance is one thing. A window that does not match the contractual description is another. The real question is technical: is this discrepancy within the acceptable limits defined by the standard and the contract?

Width per plan 1.80 m Actual measured width 1.74 m Difference ΔL = 6 cm Schematic diagram: Window dimensional discrepancy

The Calculation That Reveals Non-Conformity

The standard NF EN 14351-1 (§5.2.2) and Article 6 of the CCTP VEFA (Special Technical Clauses for sale of future completion) set dimensional tolerances. For a window with nominal width L ≥ 1 m, the allowable tolerance is ±5 mm (0.5 cm) on the manufacturing dimension, and an installation tolerance of ±1 cm may be considered during construction. The theoretical total allowable discrepancy is therefore: ΔL_max = √(0.5² + 1²) ≈ 1.12 cm (root mean square error calculation).

Take your case in Nice: L_plan = 1.80 m (180 cm). L_actual = 1.74 m (174 cm). ΔL_measured = 180 – 174 = 6 cm.

Comparison: ΔL_measured (6 cm) > ΔL_max (1.12 cm). The discrepancy is 5.4 times greater than the allowable tolerance. This is not a “construction tolerance”; it is a proven non-conformity. What this means concretely: the glazed area is reduced by (1.80×2.00) – (1.74×2.00) = 0.12 m² per window. Over 10 windows, you lose 1.2 m² of light and view, an essential criterion in Nice where sunshine and panoramas are part of the contract.

Consequences Over Time If Nothing Is Done

In the short term (6 months), the impact is aesthetic and contractual. You do not have what was sold.

In the medium term (2 years), pathologies may appear. A window frame poorly dimensioned for the opening can create stress points. The mechanical stress on the fixings increases. We can estimate the additional stress with a simplification: σ = F/A. If the wind force in Nice (characteristic value ~ 600 N/m²) applies to a reduced surface but with fixings designed for a different geometry, the localized pressure on the anchor points can exceed the initial design by 15-20%, accelerating material fatigue.

In the long term (5 years), risks include peripheral cracking of plasters, water infiltration if the perimeter seal is compromised by poorly executed repairs to fill the gap, and a depreciation of your property’s value. The cost of later replacing a window with the correct dimensions, outside warranty, can be around €1,500 to €2,500 per unit (supply and installation in renovation on the French Riviera), not including associated disorders.

Recourse and Guarantees: What You Can Demand

The guarantee of perfect completion (2 years) and the ten-year liability apply. The technical basis is non-conformity to the contract (CCTP Art. 6, §3.1) and to standard NF EN 14351-1 (§5.2.2). You must act quickly. Send a registered letter with acknowledgment of receipt to the developer with the quantified finding (6 cm discrepancy vs. 1.12 cm tolerance). If he contests, request a judicial expert (Nice Judicial Court) for a contradictory measurement with a total station (accuracy ±1 mm). What no one says: often, simply sending a well-supported technical calculation like this is enough to make the developer move, because he knows that the Nice court regularly follows expert appraisals on this type of VEFA dispute. Demand compliance: replacement of windows to contractual dimensions.

Frequently Asked Questions

What is the acceptable tolerance for window dimensions in a VEFA in Nice?

The allowable tolerance for a window with nominal width ≥ 1 m is ±5 mm on the manufacturing dimension and ±1 cm on installation, giving a combined maximum of about 1.12 cm (root mean square). Any deviation beyond this is considered a non-conformity.

📅 Mis à jour le 06/08/2026 — Par Cassini Expertise, expert bâtiment indépendant 06 & 83. Devis gratuit : 04 22 46 06 04.

Questions fréquentes

What to do if VEFA windows dimensions don't match plans?

You should first document the discrepancy with photos and measurements, then formally notify the developer (promoteur) in writing, citing the VEFA contract and the approved plans. If the developer fails to rectify the issue or reach a settlement, you can escalate to a legal expert or file a claim within the 10-year decennial liability period, but act promptly as delays may affect your rights.

Can you refuse VEFA apartment if window sizes are wrong?

Yes, you can refuse to take possession if the deviation is significant and affects the conformity of the dwelling. However, the refusal must be justified and formalized during the handover (livraison) by noting the non-conformity on the handover report. If the issue is minor, the developer may offer a price reduction or a repair plan; otherwise, legal action may be necessary to force compliance or seek damages.

How to claim compensation for non-conforming windows in VEFA?

To claim compensation, you need to prove the non-conformity by comparing actual measurements with the plans and any technical specifications. Send a formal claim (mise en demeure) to the developer, and if unresolved, consider mediation or arbitration. If that fails, you can sue in court within the applicable limitation periods (often 5 years for non-conformity, but check your contract). Compensation may cover repair costs, loss of value, or even termination of the sale in severe cases.

📅 Mis à jour le 19/09/2026 — Cassini Expertise, expert bâtiment indépendant (06·83·13·40).