Obligation to insulate buildings during roof repairs or repairs

Verified 21 June 2024 - Directorate for Legal and Administrative Information (Prime Minister)

During important work of recharge or reduction roofing of existing buildings, thermal insulation work must be carried out. There are some exceptions. We're explaining the regulations.

Vessels concerned

Works ofthermal insulation must be carried out during major renovation or roof repair work on existing buildings. That applies buildings for use:

  • Dwelling
  • Office
  • Commercial
  • Teaching

This also applies to hotels.

Excluded buildings

This obligation does not apply the following categories of buildings:

  • Buildings and parts of buildings where no energy is used to regulate indoor temperature
  • Provisional construction planned for a period of use of 2 years or less
  • Independent buildings with a floor area of less than 50 m²
  • Buildings for agricultural, craft or industrial use, other than residential premises, which require only a small amount of energy for heating, domestic hot water production or cooling
  • Buildings serving as places of worship
  • Buildings which have received the 'Remarkable contemporary architecture' label
  • Historical monuments classified or inscribed inventory, where this would have the effect of changing their character or appearance in an unacceptable manner.

The regulations depend on the type of work to which the building is subject:

Répondez aux questions successives et les réponses s’afficheront automatiquement

Facade renovation

General case

The developer has to carry out thermal insulation work on the walls concerned by reclamation work. This applies when all of the following conditions are met:

  • The walls which are the subject of renovation work:
    • Are walls of heated rooms overlooking the outside.
    • Consist of a surface of more than 50%, excluding openings, of terracotta, concrete, cement or metal.
  • The work involves at least 50% of a wall of a building, excluding openings:
    • Either the rebuilding of the existing coating
    • Replace an existing siding
    • Let's put a new parliament in place
Exceptions

There may be exceptions to this obligation, in the following cases:

  • If there is a risk of pathology of the frame related to any type of insulation. The developer must then justify the technical risk incurred by producing a reasoned note drawn up by a person skilled in the art under his responsibility.
  • If the insulation work does not comply with easements or may not comply with the rules relating to land law, property rights or the appearance of facades and their layout. For example, if the insulation work did not comply with obligations regarding citizenship or easements.
  • If the insulation work results in changes in the condition of the external parts or of the architectural and decorative elements of the construction which conflict with the requirements for remarkable heritage sites, the historic landmarks, the registered and classified sites, or with the rules and requirements defined in the local city planning plan (PLU)
  • If there is a clear disproportion between the advantages of insulation and its disadvantages of a technical, economic or architectural nature. This applies in particular if the improvements made by this insulation have too great a negative impact in terms of the quality of use and operation of the building, of modification of the exterior appearance of the building with regard to its architectural quality, or of additional cost.

One obvious disproportion ROI time is systematically established, in the case of facade removal, in the following cases:

  • Building built after 2001
  • Isolated façade after 2008
  • Facade already insulated to achieve a thermal resistance of 2,3 m².K/W or more (e.g. with 8 cm mineral wool, 9 cm polystyrene, 10 cm wood fiber insulation or 10 cm hemp wool)
  • A building that has already been subject to an energy audit (less than 10 years old) demonstrating that insulation is not appropriate (technical, legal, architectural or economic constraints described above)
  • Presence of balconies less than 1 m deep
  • Insulation works requiring the identical reconstitution of existing models
  • Insulation work requiring asbestos removal work

Otherwise, overt disproportion is established in the following situations:

  • Or if insulation from the outside would significantly degrade the architectural quality. The contracting authority shall justify the heritage or architectural value of the facade and the damage to it by producing a reasoned note drawn up by an architect or by a person approved in architecture or holding a receipt and entered in a regional list of architects or in the annex thereto.
Who shall I contact
  • Or if the time to return on investment of the additional cost of adding insulation, less public financial aid, is more than 10 years. The plate included in the calculation of this additional cost is the cost of insulation work and all other costs associated with adding insulation. The contracting authority shall justify the time of return on investment either by producing a note drawn up by a person skilled in the art under his responsibility (experienced specialist staff) or by establishing that its duration is greater than 10 years in comparison with the standard cases referred to in the guide referred to in the preceding subparagraph.

The ROI calculation method is available on pages 8 to 10 of a dedicated guide published by the Ministry responsible for construction and the Agency for Ecological Transition (ADEME).

Roofing Rehabilitation

General case

The developer shall perform thermal insulation of the roof or high floor of the last occupied or heated level when a building undergoes roof repair work, if such work includes the replacement or covering of at least 50% of the entire blanket, excluding openings.

Exceptions

There may be exceptions to this obligation, in the following cases:

  • If there is a risk of pathology of the frame related to any type of insulation. The developer must then justify the technical risk incurred by producing a reasoned note drawn up by a person skilled in the art under his responsibility (competent specialist staff).
  • If the insulation work does not comply with easements or may not comply with laws or regulations relating to land rights, property rights or the appearance of facades and their layout. For example, if the insulation work did not comply with water flow or sunshine obligations.
  • If the insulation work results in changes in the condition of the external parts or of the architectural and decorative elements of the construction which conflict with the requirements for remarkable heritage sites, the historic landmarks, the registered and classified sites, or with the rules and requirements defined in the local city planning plan (PLU)
  • If there is a clear disproportion between the advantages of insulation and its disadvantages of a technical, economic or architectural nature. This applies in particular if the improvements made by this insulation have too great a negative impact in terms of the quality of use and operation of the building, of modification of the exterior appearance of the building with regard to its architectural quality, or of additional cost.

One obvious disproportion ROI time is systematically established, in the case of roof repairs, in the following cases:

  • Building built after 2001
  • Roof or high floor of the last inhabited level isolated after 2008
  • Roof or high floor of the last inhabited level already insulated to obtain a thermal resistance of 2,5 m².K/W or more (e.g. with 10 cm mineral wool or polystyrene, 12 cm wood fiber insulation or 12 cm loose cellulose wadding).
  • A building that has already been subject to an energy audit (less than 10 years old) demonstrating that insulation is not appropriate (technical, legal, architectural or economic constraints described above)
  • Insulation work requiring asbestos removal work

Otherwise, overt disproportion is established in the following situations:

  • Or if insulation from the outside would significantly degrade the architectural quality. The contracting authority shall justify the heritage or architectural value of the facade and the deterioration incurred by producing a reasoned note drawn up by an architect, a business of architects or a person approved in architecture or holding a receipt and entered in a regional architects' table or in the annex thereto.
Who shall I contact
  • Or if the time to return on investment of the additional cost of adding insulation, less public financial aid, is more than 10 years. The base used to calculate this additional cost includes the cost of the insulation work and all other costs associated with the addition of insulation. The contracting authority shall justify the time of return on investment either by producing a note drawn up by a person skilled in the art under his responsibility or by establishing that its duration is greater than 10 years in comparison with the typical cases referred to in the guide mentioned in the preceding paragraph.

The ROI calculation method is available on pages 8 to 10 of a dedicated guide published by the Ministry of Construction and the Agency for Ecological Transition (ADEME).

FYI  

The work of thermal insulation of walls, floors and roofs must be carried out in accordance with the requirements indicated in a decree available on Légifrance:

Requirements for insulation work on buildings

Legifrance

Pour en savoir plus

Who can help me?

The public service accompanying companies

Do you have a project, a difficulty, a question of daily life?
Simple and free - you will be called back within 5 days by THE advisor who can help you.

Get a phone call with an advisor