Why France suits a factory-built house
Two things make France a natural destination for us. The first is distance: the factory is in Spain, and most French plots are a short road journey away with no border formalities and no sea leg. France is consistently one of the least expensive countries in Europe for us to deliver to, and short transport means fewer route constraints and wider modules.
The second is RE2020, and it is the more interesting one. France is the first major European market to regulate the carbon of a new house and not only its energy consumption — which turns out to favour exactly the way we build. That is the subject of its own section below, and it is the single strongest argument for off-site construction in this market.
The permis de construire and the PLU
A new house in France needs a permis de construire, applied for at the mairie of the commune. The instruction period is normally two months for a single dwelling, extended to three where a further consultation is required — most commonly where the plot lies within the protected setting of a historic monument or a heritage area, which brings in the Architecte des Bâtiments de France and, with it, close control over form, materials and colour.
What you may build is set by the commune's plan local d'urbanisme, or by a simpler communal map or the national rules where no PLU exists. The PLU governs footprint, height, position relative to boundaries, roof pitch, materials and often colour. In the south this is frequently prescriptive in ways that matter to a contemporary design — tile type, render colour, the pitch of a roof — so the design has to be developed against that document from the beginning rather than adjusted to it later.
Three procedural points that catch international clients out:
- An architect is compulsory above 150 m². French law requires a registered architect for any dwelling above 150 m² of floor area, which in practice means every house we build there. Our designs are delivered through a French registered architect as a matter of course.
- There is a third-party challenge window. Once granted, the permit must be displayed on the site, and third parties — neighbours, associations — have a period from that display in which to bring a challenge. It is the main programme risk on a French project, and it is worth managing socially before it becomes a legal matter.
- Completion is a formal step. Works are declared open at the start and a declaration of completion and conformity is filed at the end, after which the authority may inspect. The house is handed over with that file complete, not with a list of things for you to do.
RE2020: the standard that rewards how we build
RE2020 replaced RT2012 for new dwellings, and it did something none of its predecessors did. Alongside the familiar energy indicators — the bioclimatic need, primary energy consumption, and a separate indicator for non-renewable primary energy — it added two new requirements:
- A summer comfort indicator measured in degree-hours, with a cap. Overheating is no longer a comfort preference; it is a compliance threshold. For a house with large glazing in Provence or the south-west, this pushes shading, orientation, thermal mass and night ventilation into the design rather than leaving them to an air-conditioning unit added later.
- Life-cycle carbon thresholds, covering both the energy used over the building's life and — for the first time — the carbon embodied in its construction. The construction threshold tightens in stages over the life of the regulation.
That embodied-carbon threshold is where our method has a direct regulatory benefit. Low-carbon structural materials, in particular engineered timber, and the sharp reduction in waste and site activity that comes with factory production, count in the calculation. The practical effect of RE2020 has been to make timber-frame and off-site construction the efficient route to compliance, and heavy carbon-intensive structures the difficult one. It also effectively excludes fossil gas heating from new detached houses, so a heat pump is the normal solution — again, easier to justify in a very airtight, very well insulated envelope.
An airtightness test on the finished dwelling is mandatory, and factory-built envelopes pass it comfortably. In France, that is not just a compliance box: it feeds straight into the energy indicators that the whole calculation turns on.
Structure, seismic zones and the soil study
Structural design follows the Eurocodes with the French national annexes. Three pieces of French zoning do most of the work in reshaping a design:
- Seismic zoning. France is divided into five seismic zones, and zones three to five — covering the Pyrenees, the Alps, parts of Provence and a broad stretch of the western coast — impose real requirements on the structural system and, for a modular house, on the connections between modules. It is not a detail that can be added at the end.
- Snow and wind zoning. Atlantic exposure, Mediterranean wind and alpine snow produce three quite different structures. A design is recalculated for the actual location as standard.
- Clay shrink–swell, and the compulsory soil study. This is the one clients have never heard of and it matters enormously. Large parts of France sit on clays that swell and shrink with moisture, and this movement is the largest single cause of structural damage to French houses. In exposed zones a geotechnical study is compulsory before building a house, and its findings drive the foundation design. Alongside it, the état des risques for the plot discloses flood, seismic and other hazards, and flood plans can constrain the finished floor level or the buildable area outright.
We commission the soil and hazard studies as part of feasibility, because the foundation is the one part of the project that cannot be built in a factory and the one most likely to surprise a budget.
Garantie décennale and insurance: the question that decides whether a foreign builder can deliver at all
If you read one section of this page, read this one. France regulates construction liability more strictly than any of its neighbours, and it is enforced not by inspectors but by notaries and banks at the moment you try to sell.
French law imposes on the builder a ten-year liability — the garantie décennale — for any defect affecting the solidity of the works or making them unfit for their purpose. Alongside it sit a two-year guarantee on equipment and a one-year guarantee of perfect completion. Crucially, the builder must be insured for the decennial liability by an insurer authorised to cover that French risk, and the client, as maître d'ouvrage, is required to hold dommages-ouvrage insurance on the works.
Why this decides projects: if you sell the house within ten years of completion, the notary will ask for the decennial insurance certificate and the dommages-ouvrage policy. Without them, the sale becomes difficult, buyers' lenders become reluctant, and you personally carry a liability that should have sat with an insurer. A house can be beautifully built and still be a resale problem for exactly this reason.
Where it applies, the contrat de construction de maison individuelle regime adds a further layer of protection — a guarantee that the house will be delivered at the agreed price and date, regulated payment stages tied to progress, and a withdrawal period. Whether that regime applies to a given project depends on how the contract is structured.
Transport: convoi exceptionnel
Modules travel entirely by road from the factory in Spain, normally over the Mediterranean corridor towards Perpignan or through the Basque corridor in the west, then onward within France. No customs, no ferry, and the shortest distances of any international destination we serve.
- Beyond the legal envelope you need an authorisation. A load exceeding the standard dimensional or weight limits requires a transport exceptionnel authorisation from the DREAL, graded by category according to size and weight, with an approved itinerary and one or more escort vehicles. Some corridors are pre-approved for heavy loads, which is a good reason to let the route influence the module sizing.
- Module width is a design decision. Wider modules mean fewer joints and better interiors but a more constrained route. That trade-off is settled during engineering against the real itinerary, not afterwards.
- The village and the driveway are the hard part. Narrow village approaches, avenues of plane trees, stone gateposts, and the ground the crane has to stand on typically determine more than the motorway leg. We survey the final approach before the modules are sized.
VAT and the taxes around the project
Work on immovable property is taxed where the land is, so French VAT applies to a house built in France. For new residential construction that is the standard rate: the reduced rates that people often hear about apply to renovation and energy improvement work on existing dwellings, not to a new build. It is a common and expensive misunderstanding.
Around the construction sit several French-specific items: the taxe d'aménagement triggered by the permit, notary fees and registration duties on the land purchase, annual taxe foncière and, for a second home, taxe d'habitation. Owners of substantial French property may also fall within the wealth tax on real estate. None of these are ours to advise on, and all of them are better understood before you commit than after.
We set out the treatment we have assumed in the project breakdown so your French adviser has something concrete to confirm.
What we handle, and what stays with you
One point of contact, in English, from the first look at the plot to handover: feasibility against the PLU and the hazard and soil studies; bespoke architecture delivered through a French registered architect; structural design to the Eurocodes with the French national annexes for the actual seismic, snow and wind zoning; the RE2020 calculation including the summer comfort and carbon indicators; the permis de construire filed at the mairie in French; the decennial insurance route and the dommages-ouvrage policy arranged rather than assumed; factory manufacturing with scheduled reporting and a visit before the modules are closed; the DREAL transport authorisation and escorts; assembly, connections and commissioning supervised by our own team; and the completion declaration filed.
The wider service and specification are on the turnkey luxury modular homes page and in the catalogue and quality specifications; the cross-border process step by step on international luxury modular homes, and the market-by-market comparison on luxury modular homes in Europe. We also publish a detailed Spanish-language guide for buyers moving between France and Spain in our buying guides.
Frequently asked questions
Do I need a permis de construire for a modular house in France?
Yes. A new dwelling requires a permis de construire from the mairie, normally with a two-month instruction period for a single house, or three months where the Architecte des Bâtiments de France is consulted because the plot lies in a protected setting. French law also makes a registered architect compulsory above 150 m² of floor area, which applies to every house we build there. Being factory-built gives no exemption.
What is the garantie décennale and why does it matter to me?
It is the ten-year liability French law imposes on the builder for defects affecting the solidity or fitness for purpose of the works, and the builder must be insured for it by an insurer authorised to cover that French risk. As client you are also required to hold dommages-ouvrage insurance. It matters because if you sell within ten years the notary will ask for both certificates, and without them the sale becomes difficult and the liability stays with you. Ask any supplier for the certificate and the insurer name in writing before paying a deposit.
Does a modular house comply with RE2020?
Yes, and RE2020 is the standard that most favours it. Alongside the energy indicators it adds a capped summer comfort indicator in degree-hours and, for the first time, life-cycle carbon thresholds including the carbon embodied in construction. Low-carbon structures such as engineered timber and the reduced waste and site activity of factory production count directly in that calculation, which has made off-site construction the efficient route to compliance. The mandatory airtightness test is also where a factory envelope performs best.
What is the compulsory soil study and do I need one?
Large parts of France sit on clays that swell and shrink with moisture, and that movement is the biggest single cause of structural damage to French houses. In exposed zones a geotechnical study is compulsory before building, and its findings drive the foundation design. We commission it, together with the état des risques disclosing flood and seismic hazards, as part of feasibility — because the foundation is the one part of the house that cannot be factory-built and the one most likely to surprise a budget.
Is France affected by seismic requirements?
In much of it, yes. France has five seismic zones, and zones three to five cover the Pyrenees, the Alps, parts of Provence and a broad stretch of the western coast. In those zones the seismic action shapes the structural system and, for a modular house, the connections between modules. It is designed in from the start rather than added at the end.
How do the modules reach a French plot?
Entirely by road from the factory in Spain, usually over the Mediterranean corridor towards Perpignan or through the Basque corridor in the west. There is no customs clearance and no sea leg, and the distances are the shortest of any international destination we serve. Loads beyond the legal limits need a transport exceptionnel authorisation from the DREAL with an approved itinerary and escort vehicles, so module width is set during engineering against the real route.
What VAT applies to a new house in France?
The standard rate. Work on immovable property is taxed where the land is, and new residential construction does not qualify for the reduced rates — those apply to renovation and energy improvement of existing dwellings. This is a common and expensive misunderstanding. Around the construction sit the taxe d’aménagement triggered by the permit, notary fees and registration duties on the land, and annual taxe foncière. Confirm your position with a French adviser.
Can you handle the whole project if I do not speak French?
Yes. Your point of contact, the drawings, the specification, the contract and the reporting are all in English, while the permit application, the dealings with the mairie, the architect of record, the insurers and the local trades are handled in French on your behalf. We coordinate with your own independent French lawyer and notaire rather than replacing them.
How much does a luxury modular home in France cost?
There is no fixed catalogue price. The budget is built on the project and broken down into architecture, manufacturing, transport, assembly, services and finishes, plus the permit and study costs, the insurance, the foundations and the utility connections. In France the items that vary most between plots are the foundations driven by the soil study and the final access for the modules and the crane.
Tell us where the plot is
Send us the commune and the cadastral reference and we will tell you, at no cost, what the PLU allows, which hazard and soil studies your plot will need and whether the modules can reach it.
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