LEGAL FEASIBILITY

Maeva Sabre (CSTB)

The state of the art about the rules and legislative aspects is based on the Kelsen pyramid model. The approach is based on directives at the European scale, then at the national scale, and finally at the local scale; it encompasses the 4 construction, energy, agriculture, and socioeconomic sectors.

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Within the legal and regulatory context, the state of the art at the national and European scales has more levers available for implementing greenhouses on rooftops. The point here is that construction regulations vary depending on the project, its scale and its location. Specialist advice should be sought for and followed. General directives orient sustainable development so as to allow for various fields of action. They favour innovations, functional and social mixing, and the preservation of natural heritage.

Obstacles increase at the local scale because of many regulations related to the diversity of sites, to urban configuration and to the typology of buildings. Obstacles can increase even more at the construction scale, where they are related to technicality, implementation, use, and people’s health and safety.

At the construction scale per se, the project can present two different configurations with their own obstacles: i) existing buildings (for renovation), and ii) new buildings.

Then, the typology of the rooftop greenhouse (RTG) (production / community / technical greenhouse) involves different ways of functioning with their own inherent obstacles, whether from the construction, energy, or farming points of view. The function of the RTG will determine which regulations it should abide by.

On an existing building, two main obstacles are likely: one is related to construction, and the other to the use of the greenhouse itself: the host building structure implies limitations for the greenhouse morphology and the farming system (conventional, hydroponic, etc.); the greenhouse use will define the issues related to energy operation and to people’s health and safety. Integration in the food-processing and economic environments also deserves to be addressed.


On a new building, obstacles are less on the construction and regulatory aspects because these have been tackled upstream. They are more linked to the economic model of the farming activity and social investment.


Although regulations differ among countries and regions, common obstacles exist. They include:

  • Building permits

  • Building controls

  • Regulations related to public calls for offers

  • The maximum constructible height depending on the size of the building

  • Constraints related to installing a crane on a busy street

  • Authorised construction budget

  • Public reception constraints

  • Environmental (or ecological) compensation

  • The limitations set by development plans

  • The operating permit

  • Rights of light

  • The trade permits

  • Health regulations

  • Health risks

  • Food safety regulations

  • Construction and horticultural production labels


For each of these points, it is also important to clearly identify the interlocutor who will help the project progress.


For example:

  • Cities, towns, local authorities

  • Urban planners

  • Urban project managers

  • Developer / owner / property manager

  • Companies / operators

  • Design offices