The layered liability regimes

	Patent defects	Minor latent defects	Ten-year
Nature of the defect	visible on inspection	slight, undetectable	affecting soundness or stability
When revealed	at acceptance	after acceptance, in use	within ten years
Basis	effect of acceptance	contractual	provision of public policy
Adjustable by contract	through reservations	yes	no

The dividing line between minor and ten-year is seriousness, assessed by reference to impairment of soundness or stability.

The dividing line between patent and latent is detectability, assessed by reference to careful and thorough examination by a normally prudent person in the same situation.

Three consequences, all favouring the client. They follow from the public-order character of the ten-year regime.

No clause can exclude or limit ten-year liability. The Court of Cassation has held that a clause limiting the architect's liability to their share of the damage was, to that extent, contrary to public policy.

No waiver is valid. The client cannot validly waive reliance on patent defects that later manifest as serious defects.

The period is one of forfeiture, which can be neither suspended nor interrupted, save by proceedings on the merits or express acknowledgment of liability. An action merely seeking appointment of an expert does not interrupt it.

That last point is a frequent trap: bringing expert proceedings believing one is preserving one's rights does not preserve them.

The distinction is decisive and regularly misapplied. It separates serious defects from ordinary faults.

Within it fall the structural works of immovable construction, and certain substantial immovable works.

Outside it fall finishing, maintenance and decoration works, and very localised repairs.

One frequent case deserves attention: water ingress. It may constitute a defect liable to endanger stability or soundness, but not systematically, and the courts assess strictly. Ingress does not mechanically engage ten-year liability.

A distinct regime, often forgotten, yet the one covering most real situations. It concerns ordinary contractual liability.

Minor defects fall outside ten-year liability but not outside all liability. The majority case law holds that contractor and architect remain liable for them after approval, on a contractual basis.

Unlike ten-year liability, that regime may be adjusted by contract, notably as to duration. It is one of the points where contractual drafting has real effect, covered in the article on the clauses that protect.

A practical consequence: a client accepting a limitation of duration on minor latent defects reduces their protection on most ordinary defects, those not affecting stability.

A technical point with considerable effects. It concerns the starting point of the periods.

Ten-year liability is not an automatic guarantee but a fault-based liability. The client must in principle prove an attributable construction defect.

A notable exception applies to defects of ground and materials, where it is accepted that architect and contractor owe an obligation of result, with a presumption of fault where damage occurs.

That is where the link with compliance with standards arises, developed in the guide on building regulations. The proof of diligence is explained there.

Four rules.

Characterise the defect before arguing the merits, characterisation determining the regime and hence the period.

Do not believe that expert proceedings preserve rights, only proceedings on the merits or express acknowledgment interrupting the ten-year period.

Draft the clauses on minor latent defects carefully, they being the only adjustable ones and covering most cases.

Do not equate water ingress with ten-year liability, the courts requiring impairment of soundness or stability.