Putting a tiny house in your garden: rules and formalities

Adding a room without touching the house, housing a relative, setting up an office at the bottom of the garden, putting up friends: a garden tiny house meets very practical needs. The rules, for their part, are those of ordinary planning law. They depend on two things: the floor area, and whether or not the house remains mobile.

Are you allowed to put a tiny house in your garden?

Yes, within the limits of the Code de l’urbanisme (French planning code) and the local urban plan (plan local d’urbanisme, PLU). There are three situations to distinguish, and they do not have the same consequences:

• Storage. The Code de l’urbanisme provides that a caravan may be stored, pending its next use, on the plot where the building that serves as its user’s residence stands (article R111-50). This is storage, not living: nobody sleeps in it.
• Occasional stays. A tiny house on wheels, treated as a caravan, can be parked on private land for up to three months a year, all periods combined, without any planning formality.
• Permanent installation. Beyond three months a year, a prior declaration (déclaration préalable) is required (article R*421-23). If the house is set down on the ground and loses its mobility, it becomes a building and follows the usual thresholds.

Which floor area thresholds apply?

For a tiny house set down permanently on the ground in a garden, the thresholds are those for any new building:

• less than 5 m² of footprint and floor area: no formality;
• from 5 to 20 m²: prior declaration;
• more than 20 m²: planning permission (permis de construire).

A threshold raised to 40 m² does exist, but it applies to extensions of an existing building in an urban zone covered by a PLU. A detached house set down at the bottom of the garden is not an extension: it stays at the 20 m² threshold. If in doubt, the planning department will decide on the basis of the application documents.

The compact models in our range sit right around this threshold: the Studio Jardin measures 20 m² over two rooms, the Terrawood 20 m² on a single level with a separate bedroom. The formalities are detailed in our guide planning permission or prior declaration.

What should you check in the PLU before ordering?

The PLU can be more restrictive than the national rules. The points that most often block a garden project:

1. Siting: minimum distance from the boundaries with neighbouring plots and from the road, often 3 metres.
2. The maximum footprint allowed on the plot, part of which is already used by the existing house.
3. The height allowed, which can be a problem for a tiny house with a mezzanine (sleeping loft).
4. External appearance: cladding colours, materials, roof pitch and colour, especially in a protected area.
5. Parking of caravans, which the regulations may ban in certain zones.

Zoning and regulations can be viewed free of charge on the Géoportail de l’urbanisme. In a protected area — near a historic monument, or on a listed site — the opinion of the Architecte des Bâtiments de France (the state heritage architect) is also required, and the processing time rises to two months.

Can someone live there all year round?

Housing a relative in a garden tiny house is possible as long as the installation is lawful and the accommodation is decent. The decree of 30 January 2002 sets the minimum: at least one main room of 9 m² with a ceiling height of 2.20 m, or 20 m³ of living volume, heating, a drinking water supply, waste water drainage and ventilation.

If the accommodation is rented out, even to a family member, these rules become enforceable and the tax rules for rental income apply. This case is covered in our guide on renting out a tiny house.

Beware of a frequent confusion: housing someone in your garden does not create a separate dwelling in the planning sense. If the project consists of creating a second self-contained dwelling on the plot, the PLU may prohibit it, and the municipality may require additional parking spaces.

What about an office or a business activity?

Working alone in a garden tiny house poses no particular difficulty: the planning rules are enough, and the installation is declared like any outbuilding. The 20 m² garden office is designed for this use.

Receiving clients changes the nature of the project: the house becomes a building open to the public (établissement recevant du public), with accessibility and fire safety obligations. Everything is detailed in our guide on the tiny house for business use.

Which utility connections from the existing house?

This is the advantage of the garden: the networks are already there. Water and electricity can be branched off the existing installation, which avoids the cost and delays of a new connection. Three precautions:

• have the electrical branch sized by a professional: an all-electric tiny house uses as much as a small home;
• bury the networks below frost depth and provide an accessible stopcock;
• check that the existing drainage can take the extra load — with off-mains drainage, the SPANC (public off-mains drainage service) must be consulted.

The supply and outlet specifications of our houses are detailed in the guide on utility connections.

Which taxes for a garden tiny house?

An authorised installation may be subject to the development tax (taxe d’aménagement), payable once only. It applies to enclosed, covered areas of more than 5 m² with a ceiling height of at least 1.80 m. For caravan and mobile leisure home pitches, the basis is a flat rate of €3,000 per pitch.

Property tax (taxe foncière), on the other hand, depends on whether the house is fixed to the ground: a house that keeps its wheels and remains movable is not liable for it. The subject is covered in full in our guide on property tax for a tiny house.

Key points

• Three months a year without formality for a tiny house on wheels; a prior declaration beyond that.
• Set down on the ground: nothing below 5 m², a prior declaration from 5 to 20 m², planning permission above that.
• The 40 m² threshold applies to extensions, not to a detached house at the bottom of the garden.
• Check siting, footprint, height and external appearance in the PLU.
• Existing networks make the project much simpler, provided they are sized correctly.

Note: this guide sets out the general rules, checked on the date shown. It does not replace personalised advice: local rules (PLU, protected areas, risk zones) may be stricter. For a specific project, contact your town hall’s planning department or the ADIL (departmental housing information agency) for your département.