Construction site insurance: liability and essential cover
A construction site is a concentration of risks: a scaffold fall, stolen materials, a copper pipe flooding the neighbour’s property, a volunteer helper injured while pouring the slab. The ten-year warranty (décennale) protects the finished building for 10 years — but during the construction phase itself, who pays when things go wrong? That is the role of construction site insurance and the project owner’s liability insurance. This guide covers every policy you should take out before laying the first brick, with a particular focus on self-build projects in France.
Why construction site insurance is essential
As the project owner (the person who builds or commissions the build), you are legally liable for everything that happens on your site. Article 1242 of the French Civil Code (formerly article 1384) establishes the principle: you are responsible for damage caused by things in your custody, and the construction site is one of them.
In practice, without appropriate insurance:
- A passer-by injured by a block falling from the scaffold → you pay
- Earthworks destabilise the neighbour’s fence → you pay
- A volunteer friend breaks their arm carrying a lintel → you pay
- A fire destroys materials stored on site → you absorb the loss
- Theft of hired tools → you reimburse the hire company
Claims can reach several hundred thousand euros for a serious bodily injury. This is an existential risk no self-builder should take.
Warning — Your standard home insurance or personal liability policy does NOT cover claims arising from new-build construction works. Household multirisks policies systematically exclude “construction works”. You need specific contracts tailored to the site.
Compulsory insurance under French law
1. Structural damage insurance (dommages-ouvrage)
Structural damage insurance (dommages-ouvrage, article L242-1 of the French Insurance Code) is compulsory for any project owner commissioning construction works. It pre-finances repairs for damage of a structural nature without waiting for a court to assign liability.
| Feature | Detail |
|---|---|
| Compulsory? | Yes, as soon as a contractor is involved within the meaning of French civil law |
| When to take out | Before the site opens |
| Average cost | 2 to 4 % of total construction cost |
| Cover duration | 10 years after handover |
| What it covers | Repair of structural defects (load-bearing elements, waterproofing, stability) |
For a complete guide to structural damage insurance, see our dedicated article on dommages-ouvrage insurance.
Tip — In a full self-build, dommages-ouvrage is almost impossible to obtain because insurers require a licensed professional to be involved. If you are building 100% yourself, work with a specialist broker to find a simplified version, or engage a project manager (maître d’œuvre) for the structural trades to unlock access to standard cover.
2. Ten-year liability insurance held by tradespeople
Every professional working on your site must hold their own ten-year liability insurance (décennale, article L241-1 of the French Insurance Code). This obligation rests with the tradesperson, not with you — but it is your responsibility to verify that they are properly covered.
Our guide on the ten-year warranty (garantie décennale) explains how to check certificates and what to do if a claim arises.
Strongly recommended insurance
3. Owner’s liability insurance (RCMO)
This is the most underestimated yet most critical insurance for the self-builder. RCMO (responsabilité civile maître d’ouvrage) covers you as project owner against damage caused to third parties during the build.
What it covers:
- Bodily injury: a visitor, a neighbour, a delivery driver injured on site
- Property damage: damage to neighbouring properties (vibration, splashing, water run-off)
- Consequential loss: nuisance suffered by neighbours (excessive noise, dust, loss of rental income)
- Third-party claims: legal action by a neighbour for losses linked to your site
What it does NOT cover:
- Damage to your own structure (that is the role of all-risks construction insurance)
- Accidents involving professional workers and tradespeople (covered by their own professional liability)
- Defective workmanship (covered by the ten-year warranty)
| Criterion | Detail |
|---|---|
| Average cost | £180 – £550 / €200 – €600 for the duration of the build |
| Take out | Before site opens |
| Duration | From opening to handover |
| Recommended limit | Minimum €1,500,000 for bodily injury |
Best practice — RCMO costs a few hundred euros and protects you against six-figure claims. It offers the best cost-to-protection ratio of all site insurance policies. Take it out without fail, even in a full self-build — it is one of the few policies that accepts self-builders without difficulty.
4. All-risks construction insurance (TRC / Tous Risques Chantier)
All-risks construction insurance, also known as TRC (Tous Risques Chantier), protects the structure under construction itself and materials stored on site.
What it covers:
- Fire and explosion on site
- Storm, hail, snow damaging the structure in progress
- Water damage (flooding, leaks)
- Theft and vandalism (materials, tools, equipment)
- Accidental collapse during works
- Breakage of materials during handling
Standard exclusions:
- Design defects (not a claim — it is an error)
- Normal wear and ordinary weather events
- Deliberately caused damage
- Wheeled equipment (vehicles, plant)
| Criterion | Detail |
|---|---|
| Average cost | 0.5 to 1.5 % of the works value |
| Take out | Before or during the build |
| Duration | Until handover plus a maintenance period |
| Excess | Typically €1,000 – €3,000 |
Tip — For a build worth €150,000, TRC costs between €750 and €2,250. Set against the risk of losing €30,000 of materials in a fire or large-scale theft, it is a worthwhile investment. Particularly important for long projects (over 12 months) — the probability of a claim rises with duration.
5. Volunteer workers insurance
This is the blind spot for many self-builders. You invite friends, family and neighbours to give you a hand at the weekend. One of them is seriously injured — who pays medical costs, lost income, and any long-term disability?
The legal position under French law:
- Mutual help between private individuals is not undeclared work if it is free, occasional and reciprocal
- But in the event of an accident, it is the project owner (you) who is liable under article 1242 of the French Civil Code
- Your household liability policy excludes construction sites
- RCMO covers third parties but not always volunteers (depending on the wording)
Solutions:
- “Volunteer” extension to your RCMO: some insurers offer a specific option (extra €50 – €150)
- Community build insurance: dedicated policies such as Twiza which specifically cover mutual-help worksites
- Individual personal accident insurance: each volunteer can take out a personal accident (GAV) policy covering them in any circumstances
Warning — If a volunteer is seriously injured on your site without appropriate insurance, you may be ordered to pay enormous damages (permanent disability, loss of earnings). Volunteer cover is a moral as well as a legal imperative. Never allow anyone to work on your site without checking your coverage.
How to choose and take out cover
The “site pack” approach
Rather than taking out each policy separately, some insurers and brokers offer site packs that bundle together:
- RCMO
- TRC (all-risks construction)
- Volunteer extension
- Legal protection for construction
The overall cost of a pack is generally lower than the sum of individual contracts, and management is simpler with a single point of contact.
Specialist self-build brokers
Standard insurers (banks, mutuals) often refuse self-builders or offer unsuitable contracts. Prioritise specialist construction brokers who know the market:
- They know which insurers accept self-builders
- They calibrate cover to the right level
- They negotiate excesses and exclusions
- They support you if a claim arises
What budget to allow?
For a build of €150,000 of works in partial self-build, here is a realistic insurance budget:
| Insurance | Estimated cost | Compulsory? |
|---|---|---|
| Structural damage insurance (dommages-ouvrage) | €3,000 – €6,000 | Yes (if professionals involved) |
| Owner’s liability (RCMO) | €200 – €600 | No but vital |
| All-risks construction (TRC) | €750 – €2,250 | No but recommended |
| Volunteer extension | €50 – €150 | No but essential |
| Legal protection | €100 – €300 | No |
| TOTAL estimate | €4,100 – €9,300 | — |
That represents 2.7 to 6.2 % of the works value — the price of peace of mind on a project that may last 12 to 24 months.
In the event of a claim during the build
The right reflexes
- Secure the area: prevent the situation from worsening and protect people
- Call the emergency services if necessary (fire brigade, ambulance)
- Photograph everything: the damage, the context, the weather conditions
- Report the claim within 5 working days (2 days for theft) to your insurer — by recorded delivery or via the online portal
- Preserve the evidence: do not move or repair anything before the loss adjuster visits (except urgent protective measures)
- List the damage with a costed estimate: purchase invoices for stolen or destroyed materials, repair quotes
Documents to keep to hand
| Document | Purpose |
|---|---|
| Insurance contracts | Policy references and numbers |
| Materials invoices | Proof of value in case of theft or destruction |
| Dated site photographs | Condition before the claim |
| Site programme | Evidence of the period of works |
| Tradespeople’s ten-year certificates | Identify responsibilities |
| Planning permission | Legitimacy of the works |
Official resources
- Service-public.fr — Construction insurance (French): insurance obligations in construction (French law)
- French Insurance Code — Article L242-1 (French): compulsory dommages-ouvrage insurance obligation
- French Civil Code — Article 1242 (French): liability for things in one’s custody
- France Assureurs: French professional insurance federation
- Twiza — Community build: mutual-help platform with volunteer site insurance
Checklist: insurance to take out before the build starts
- Owner’s liability insurance (RCMO) taken out
- RCMO limit sufficient (minimum €1,500,000 for bodily injury)
- Structural damage insurance (dommages-ouvrage) taken out (or impossibility documented)
- All-risks construction insurance (TRC) taken out if budget > €100,000
- Volunteer extension activated or community build insurance in place
- Ten-year certificates for all tradespeople collected and verified
- Policy numbers and insurer contacts displayed on site
- Invoices for all materials filed for justification in the event of a claim
- Dated site photographs taken at each stage
- Claims reporting procedure known (5-day / 2-day theft deadline)
- Legal protection for construction taken out
- Future home insurance scheduled for the handover date
Construction site insurance is not a luxury — it is the seatbelt of your self-build project. RCMO alone, for a few hundred euros, protects you against the most financially devastating claims. Combined with TRC and a volunteer extension, you cover the main risks that can turn a dream build into a financial nightmare. Take everything out before laying the first brick, and file the contracts alongside your ten-year certificates — in 10 years, you will be glad you have them.