Structural diagnosis of multi-unit buildings: instructions for condominiums and project owners
It was highly anticipated in the construction sector. Decree No. 2025-814 of August 12, 2025 is now in force.
It clarifies the outlines of the mandatory structural diagnosis in certain sectors delimited by the municipalities. Who is affected, at what rate, by whom, and with what deliverables? What changes should be made regarding the possibility of replacing this diagnosis with a draft multi-year work plan (PPPT) in co-ownership?
With this new decree, municipalities can delimit areas where collective buildings must carry out a structural diagnosis. The deliberation is annexed to the PLU within three months and notified to the owners or trustees. From this notification, the interested parties will have 18 months to submit the report to the municipality.
In co-ownership, the PPPT prepared by a professional meeting the same skill and insurance requirements can serve as a diagnostic. In the event of a deficiency, the mayor can have the diagnostic carried out automatically at the owners' expense.
In this article, we take stock of the developments in the mandatory structural diagnosis.
1) Why is it necessary to carry out a structural diagnosis?
The structural diagnosis responds to a simple objective: to prevent the risks of collapse and to secure the occupants and levels in the fabric of old or degraded housing .
Following several significant accidents, the “Degraded Housing” law of April 9, 2024 gave municipalities the power to take the initiative: to map out high-risk areas and to initiate, at regular intervals, a check on the solidity of buildings (see article L.126-6-1 of the Construction and Housing Code). The decree of August 12, 2025 thus sets out the operational procedures in line with these legislative developments (content of the report, skills of the participants, information procedures).
2) Who is affected and when?
This system applies to collective residential buildings located in areas delimited by resolution of the municipal council. This resolution is annexed to the PLU, the urban planning document in tenant place or the municipal map within three months, then notified to the owners or trustees (who in turn inform the co-owners).
Failing this, a display in the town hall and on the facade of the building constitutes notification.
From the date of notification (or the latest posting date), the period runs for 18 months to have the diagnosis carried out and send the report to the municipality. Subsequently, the law provides for a periodicity of at least ten years after 15 years since the acceptance of the works.
3) What should the diagnosis contain? What skills does it require?
The person carrying out the diagnosis must demonstrate certain skills in this area: construction methods, calculations and modeling, geotechnics, pathologies, safety standards. They must also have professional liability insurance and demonstrate independence and impartiality.
The report , submitted in digital format , includes at least the identification of the contractor and their insurance cover, the description of the building (type, period, location), the inventory of structural elements and observed defects, as well as the analysis of the latest work and, where appropriate, recommendations: additional investigations, safety measures and prioritized list of work.
In practice, the mission is not limited to a simple visual inspection: it also requires access to technical archives . The owner or the condominium association must submit the minutes of the general meeting, descriptions, plans, existing diagnoses, danger or safety orders from the last ten years, and – if already established – the PPPT project.
With this in mind, we therefore advise you to anticipate these document flows when ordering to avoid delays.
4) Can this diagnosis be replaced by a PPPT?
Yes . Article L.126-6-1 of the CCH provides that in co-ownership, the obligation of diagnosis can be satisfied by the development of the PPPT (Project of multi-year work plan), provided however that the professional meets the same requirements of competence and guarantees as for a structural diagnosis.
The PPPT is then sent to the municipality within the same 18-month period. This solution has the advantage of avoiding a double study if the co-ownership has already planned its renovation.
However, be careful to check the scope of the PPPT mission (explicit consideration of structural strength and disorders ). If in doubt, the additional structural analysis must be contractually agreed.
5) What are the concrete effects of these developments?
The annexation of sector boundaries to the PLU or the municipal map improves the publicity and traceability of obligations in the sectors concerned.
On the ground, the trustees must include the process on the agenda of the AGM, organize access to common areas, frame intervention authorizations and plan the return to the AGM on the recommendations of the report.
On the part of the communities, the notification triggers the deadline and facilitates follow-up in the event of failure ( automatic implementation , recovery of costs as in the case of direct contributions ).
6) What contractual and insured impacts?
In your diagnostic contracts or framework agreements, it is appropriate to specify the perimeter concerned (items that can be visited, additional investigations on order), the restitution deadlines compatible with the 18-month deadline, the access conditions (keys, cradles, surveys), the ownership and reuse of the deliverables, the insurance of the speaker and his declaration of independence .
In the CCTP of the works, it should be remembered that the structural recommendations from the report are imposed on the programming and phasing, which also requires planning the interfaces with the additional diagnostics (geotechnical, networks). Inform your insurer (professional liability / DO / ten-year) of the characterized disorders and the recommended conservative measures.
Frequently Asked Questions
Does diagnosis block localization?
No, the diagnosis is an assessment tool. In the event of serious problems, police or security measures may be required, and work may be decided upon; but the obligation primarily concerns the completion and transmission of the diagnosis (or the PPPT).
Who pays?
The diagnosis is the responsibility of the owners or the condominium association. In the event of a failure to do so, the municipality may have it carried out automatically and recover the cost, as in the case of direct contributions.
What to do outside the municipal sector?
If the building is not located within a defined perimeter, the specific obligation does not apply. However, there is nothing to prevent a voluntary order for a diagnostic structure (or the extension of the DTG/PPPT) when a risk is suspected.
Does PPPT always replace diagnosis?
Yes, in co-ownership and under conditions : skills and guarantees identical to those required for the structural diagnosis, and transmission of the PPPT project to the municipality within the same time frame . Failing this, carry out a dedicated diagnosis.
Conclusion
The new framework provides municipalities and private stakeholders with an operational tool to detect weaknesses and act before disaster strikes.
For professionals in the sector, the challenge is not purely formal. Their goal is to transform this report into an action plan, with a realistic safety and work schedule that is compatible with co-ownership governance and project management and business contracts.
To secure your operations in this context, call on Maître de Poulpiquet for an audit of the situation, your current contracts and advice adapted to the situation of your collective building.
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