The conversion of a farm building into residential use requires that the building is fully enclosed by a roof and walls, a French court has ruled.

National and local planning regulations in France most often formally prohibit the construction of new dwellings in the open countryside, or in those areas zoned for agricultural use.

Nevertheless, the change of use of old agricultural buildings for residential use is frequently permitted, provided the application meets any relevant conditions set out in the local planning regulations.

In the parish of La Rivière, in the department of Isère, Rhône, the local plan (plan local d'urbanisme) permitted the conversion of former agricultural buildings provided, inter alia, there was no increase in the volume of the building.

The plan stated that in the “zone de richesses naturelles à protéger en raison notamment de la valeur agricole des terres”, only certain types of construction were permitted, including "la transformation des bâtiments existants en gîtes ruraux sans changement de volume."

A couple made a planning application to the local planning authority to convert a building previously use for walnut drying into a gîte rurale.

Planning permission for the conversion of the building was granted by the local mayor, but this was contested by a neighbour.

The challenge was based on the fact that a large part of the building the couple were proposing to convert consisted of a temporary roof area supported on pillars, which was not enclosed by walls.

The court of appeal sitting in Grenoble found no objection to the application, but this was overturned by the Conseil d’Etat, the higher administrative court, on the grounds that the building to be converted by the couple was not entirely enclosed.

Accordingly, the proposed works could not be regarded as the transformation of an existing building without change of volume.

Arthur Cutler of planning consultants French Plans comments: "To be considered existing floor area as defined by planning regulations a building must have a roof and be fully enclosed (clos et couvert). Provided a building meets these criteria, under normal circumstances, there should be no opposition to an application to convert.

Perhaps what is most surprising about this case is the fact that neither the local planning authority nor the court of appeal in Grenoble were aware of basic french planning law regarding a change in volume."