To Install a Greenhouse in the Garden: What is the Legislation in Force?

Sometimes considered a permanent installation, a greenhouse may require authorization and/or building permit before being put in place.

In a garden, on a terrace or balcony: there is today a type of greenhouse for each configuration. It can be leaned, urban or old-fashioned with metal structure and safety glass or polycarbonate, a volume ranging from 1.5 m2 up to 40 m2 and even more … Its volume and its technical characteristics define the legal obligations.

Alexis Deblocq, from ACD Serres , helps us to see more clearly …

With or without authorization …

A greenhouse installed without a permit or declaration, it is possible if you choose a freestanding model: it includes a metal base that avoids a grading prior to installation, which exempts it from permits and taxes and allows it to be eventually moved. In addition, below 20 m2, no steps are required. So for a first greenhouse, choose a freestanding of 20 m 2 maximum.

On the other hand, several cases involve formalities: first, if you absolutely need to do an earthwork by pouring, for example, a concrete slab, on marshy ground or to level a slope. This is a first step to declare in the town hall.

If you wish to install a greenhouse of more than 20 m 2 , same obligation to obtain an authorization and a building permit: inquire with your municipality because some cities tolerate up to 40 m 2 (since January 1, 2016) and each town hall may have its own rules.

The specificities can also be regional (landscapes classified as in the Pays de la Loire region, request for exemption from the mayor of Paris, which, in principle, does not accept greenhouses …).

Finally, subdivisions are governed by their own regulations and should be known before installing a greenhouse at home.

Three criteria to take into account

To make sure you do not go wrong before you start buying a greenhouse, determine your needs in terms of floor space, height and volume.
To make sure you do not go wrong before you start buying a greenhouse, determine your needs in terms of floor space, height and volume. (© SerreACD)

Floor area, volume and height: these are the three criteria to consider when choosing your greenhouse. Beyond its surface, it is its overall capacity that you must study. Imagine planting tomatoes, transplanting on a work table, placing your seedlings or plants on shelves … It takes space to garden well under glass.

In height, what a pleasure to suspend strawberries, to run a vine … High plants also give a natural shade very interesting for the success of crops. If you want to grow a lemon tree, an orange tree, the greenhouse must be high enough to let them flourish. Gutters exceeding 1.80 m also require a passage in the town hall.

Finally, in parallel with your efforts, talk about your greenhouse project to your neighbours to make sure you make it a vector of social link! And offer them to offer them, why not, your first 5 kilos of tomatoes or to receive them for an aperitif around your first harvests!