How much does damage-to-works insurance cost? The real price in 2026

It's one of the first questions any future property owner asks: how much is this famous damage-to-works insurance (Dommage Ouvrage) going to cost me? The estimates you read here and there often swing between 1% and 8% of the works budget, without anyone really explaining where these gaps come from. In 2026, here are the true orders of magnitude.

The price ranges in 2026

For an equivalent works budget, the cost of a Dommage Ouvrage policy can vary threefold. Here are the most representative orders of magnitude in the 2026 market:

New build of a detached house: 1.2 to 2.5% of the total cost of the works
Extension or adding a storey: 2 to 3.5%
Major renovation (affecting the structure): 2.5 to 5%
Works in a co-ownership or collective building: 1.5 to 3%
Project in a high-risk area (clay, seismicity, mountain): a surcharge of 20 to 40%

For a project with €200,000 (excl. tax) of works, you should therefore expect in practice between €2,400 and €10,000 for the Dommage Ouvrage premium, depending on the context. A minimum premium of around €2,000 most often applies, even for small projects.

The 6 factors that make the rate vary

1. The nature and scale of the project

A "turnkey" new-build project with a recognised individual home builder (constructeur de maisons individuelles, CMI) will be cheaper to insure than a major renovation of an old building involving several independent trades. Technical complexity and the number of parties involved mechanically increase the risk.

2. The profile of the builders

The insurer systematically examines:

the track record and financial health of the companies;
the validity and the coverage of their ten-year warranty;
their past claims history;
their qualifications (Qualibat, RGE, etc.).

A team of builders with solid profiles can bring the premium down by 15 to 25%.

3. The geographic area

Not all plots are equal. The following are notably taken into account:

the nature of the soil (swelling clay, fill, flood zones);
seismicity (zones 3, 4, 5);
exposure to climate risks (mountain, coast, clay shrinkage and swelling);
the geological history (cavities, former mines).

4. The soil study

A G2 PRO study (standard NF P94-500) carried out before the project can often reduce the premium by 10 to 20%. The insurer considers the risk to be better managed. For a study costing €2,000 to €4,000, the return on investment is often positive.

5. Optional coverages

The basic Dommage Ouvrage covers the décennale (ten-year liability). But you can add:

the proper-functioning warranty (separable equipment, 2 years);
the consequential non-material damage cover (rehousing costs, loss of rent);
the collapse-before-handover cover;
the damage-to-existing-structures cover (renovation of an old building).

Each typically adds 10 to 25% to the base premium.

6. Brokerage and putting insurers in competition

This is often the most effective lever. The same project can receive quotes differing by 30 to 50% from one insurer to another. A specialist broker puts several companies in competition and negotiates on your behalf.

When do you pay the premium?

The premium is paid in a single instalment, when the policy is taken out, before the site opens. Some contracts allow for payment in two instalments:

80 to 90% when taking out the policy;
the balance after the handover of the works and the provision of the final supporting documents.

Note that the Dommage Ouvrage premium is a flat fee: it covers the 10 years to come and will not be called on again, except in the event of a significant change to the project.

Can you finance the Dommage Ouvrage within your mortgage?

Yes, and it's often even good practice. The Dommage Ouvrage premium can be:

built into the bank's overall financing plan;
taken into account in the financing plan of a construction loan;
treated as a deductible expense in certain rental-investment arrangements (subject to tax conditions).

Concrete levers to optimise your premium

Several actions can significantly reduce the cost of your Dommage Ouvrage:

Carry out a G2 soil study before submitting the building permit.
Choose insured and qualified builders, with a current décennale and a clean history.
Document the project precisely: detailed technical specification, plans, CCTP (technical specifications document).
Put several insurers in competition through a broker.
Adjust the optional coverages to your real needs.
Plan ahead when taking out the policy: a file put together in a rush is almost always more expensive.

And for a modest renovation?

If you renovate your house without touching the structure, you probably won't need a Dommage Ouvrage (see our article on the obligation for individuals). On the other hand, as soon as a load-bearing wall, a framework, a roof or the waterproofing is affected, the Dommage Ouvrage becomes mandatory again — and its premium is calculated on the value of the works concerned, not on the whole project.

In summary

Expect 1 to 5% of the cost of the works, with an average of around 2% for new builds.
The minimum premium is often around €2,000, whatever the size of the project.
The profile of the builders, the soil and the nature of the project are the main factors of variation.
A G2 study and a well-prepared file can bring the premium down by 15 to 25%.
The premium is paid in a single instalment, before the site opens, and can be built into your financing.

Need support?

Comparing Dommage Ouvrage offers on your own takes time and requires understanding the subtleties of each contract. Our team of brokers guides you in choosing your damage-to-works insurance, negotiating the best terms on your behalf. Request a personalised quote or get in touch with an adviser.