How to check a tradesperson's décennale certificate before signing a quote

Are you about to sign a quote for building a veranda, re-roofing, or extension works? Before you sign, take 10 minutes to check your tradesperson's décennale (ten-year structural liability) certificate. This article is for you — the private individual acting as client (maître d'ouvrage) — who wants to avoid nasty surprises at the first sign of a defect.

Why this check is crucial

The décennale is the insurance that will compensate you if, within the 10 years following handover, a serious defect appears: structural cracks, water ingress, a waterproofing failure, the failure of an integrated heating system. Without a valid certificate, you risk:

Compensation refused by the insurer if the tradesperson was not covered for that activity
An endless claim against an insolvent company
Having to fund the repair of the defect yourself

The certificate is issued by the tradesperson's insurer. It proves that, on the date the site opened, your contractor was indeed insured for the activities carried out. Ask for it systematically before signing.

The 5 points to check on the certificate

1. The insurer's identity

The certificate must name a real insurance company (Generali, Allianz, MAAF, etc.), not just a broking firm. A broker acts as an intermediary; it does not provide the insurance itself.

To check:

The company's full name
Its authorisation number or registered office
The claims handler's contact details

If only a broker's name appears, with no mention of the actual insurer, ask which company is carrying the risk. No serious professional will refuse to answer.

2. The validity dates

The certificate is valid for a specific period, usually a calendar year. Three rules to observe:

The start date of the works must fall within the validity period
An expired certificate is worthless, even by a few days
If the project spans several months, ask for an up-to-date certificate at the time the site opens

For a long project (new construction, major renovation), request a new certificate each new year if handover has not yet taken place.

3. The activities covered (the most important point)

This is the most common trap. A décennale certificate lists precisely the activities insured. If the tradesperson carries out an activity that is not listed, the insurer can refuse cover.

Concrete examples of pitfalls:

A roofer insured only for roofing will not be covered if they fit a skylight that falls under specific waterproofing
A bricklayer insured for structural work is not necessarily covered for a swimming pool or for external thermal renovation
A plumber insured for sanitary plumbing is not covered for heating if they have not declared it

Check that every type of works in the quote appears expressly in the list of activities. If in doubt, ask the insurer for written confirmation.

4. The policy number and the SIRET

Two essential pieces of administrative information:

The insurance policy number: identifies the tradesperson's contract
The company's or auto-entrepreneur's SIRET (business identification number): confirms that this really is your tradesperson, and not a namesake

The SIRET on the certificate must match exactly the one on the quote. A discrepancy, even of a single digit, is a warning sign.

5. The geographical area covered

Some certificates limit cover to mainland France (France métropolitaine). If your project is in an overseas territory, check explicitly for the "DOM-TOM" mention or the specific geographical area. A "mainland only" certificate does not cover you in Guadeloupe or on Réunion.

Also check that there is no restriction by département (rare, but possible with certain contracts).

The warning signs that should send you running

In particular, be wary of these situations:

A certificate sent as a blurry photo or an illegible photocopy
The mention "application in progress": no certificate = no cover
Vague activities listed ("building works") with no detail
A refusal to provide the insurer's contact details
A very recent issue date on the certificate for a very old company
A certificate in the name of another company than the one on the quote

How to confirm validity with the insurer?

If you have any doubt, nothing stops you from contacting the insurer directly as named on the certificate. Give the policy number and the company's SIRET, and ask for confirmation:

That the contract is indeed in force on the date the site opens
That the planned activities are covered
That the premiums are up to date (non-payment can suspend cover)

Insurers are used to this type of request and respond quickly, especially in writing.

Keep the certificate safe

Once validated, archive the décennale certificate together with the quote, the invoices and the works handover report. These documents will be indispensable:

To activate the warranty in the event of a claim
For the Dommage Ouvrage insurance (where applicable)
For the resale of the property within 10 years: the notaire (public notary) will ask you for them

In the event of a company failure, it is this certificate that will make it possible to trace the insurer and invoke the warranty, even if the company no longer exists.

In summary

Ask for the décennale certificate before signing the quote, never after
Check 5 points: insurer, dates, activities, policy/SIRET, geographical area
Every activity on the project must appear expressly on the certificate
Keep the certificate for at least 10 years after the works finish
If in doubt, contact the insurer directly

Need some guidance?

Are you preparing a construction or renovation project? An expert reading of the certificate can save you costly disputes. Our team of brokers will support you in securing your works. Request a personalised quote or get in touch with an adviser.