Since September 1, 2026, the reform of MaPrimeRénov’ has reshuffled the cards for anyone planning a renovation project. Individual works (insulation of walls, window replacement, ventilation, thermodynamic water heaters) are no longer eligible for funding separately under this scheme. Any project preparation must now incorporate this constraint from the sketch stage, or risk seeing the actual budget explode compared to initial estimates.
MaPrimeRénov’ after September 2026: eligible works and supported pathways
Decree No. 2026-822 of August 25, 2026, has removed several operations from the “by gesture” pathway that the majority of renovation guides continue to recommend without caution. Insulation of attics, walls, flat roofs, window replacement, ventilation, thermal solar, and wood heating are no longer covered as isolated interventions.
The operations still eligible for the by gesture pathway mainly concern certain heat pumps, connection to a heat network, and the removal of an oil tank. For everything else, the supported pathway becomes the only framework that grants access to significant aid.
This supported pathway imposes two structural conditions: aiming for a gain of at least two classes in the energy performance diagnosis (DPE) and integrating at least two categories of insulation works. Support from Mon Accompagnateur Rénov’ is required, which adds a delay of several weeks even before the start of the work. We recommend seeking this support as early as the diagnostic phase, before contacting companies.
The available resources about bricodeco-home.fr allow for identifying the types of works concerned and cross-referencing feedback on recent projects.
Technical sequencing of an interior renovation project
A poorly sequenced project generates costly rework. The intervention logic follows an order dictated by the physics of the building, not by the aesthetic preferences of the project owner.
Enclosure and coverage before finishing work
Any intervention on the envelope (roof, exterior joinery, external insulation) precedes interior work. Applying a finishing coat or flooring before addressing water infiltration condemns these finishes in the short term.
Insulation and ventilation must be addressed simultaneously. Insulating without reviewing air renewal creates a confinement that promotes condensation and mold. This is the most common technical error on partial projects.
Networks before partitioning
The passage of electrical, plumbing, and mechanical ventilation ducts occurs before the closure of partitions. Modifying a network after installing drywall involves chases, rework of the finish, and a disproportionate cost compared to the time initially saved.
The typical sequencing for a complete housing project follows this progression:
- Demolition, cleaning, and exposing load-bearing structures for visual diagnosis of pathologies (humidity, cracks, termites)
- Reinforcement of the structural work if necessary (lintels, floors, foundations), then treatment of the envelope (roof, insulation, joinery)
- Installation of all technical networks (electricity, plumbing, mechanical ventilation, home automation) before partitioning
- Partitioning, installation of wall coverings and flooring, then installation of sanitary equipment and kitchen
- Finishing touches (painting, tiling, lighting) and contradictory reception of the project
Choosing insulation materials: balancing performance and project constraints
The choice of an insulator is not limited to comparing thermal conductivity coefficients. Moisture resistance, available thickness, and fire behavior condition the actual feasibility of the project.
In renovation, the available thickness is often the limiting factor. A low lambda insulator allows achieving the desired thermal resistance with less thickness, which preserves the living space. Polyurethane panels or vacuum insulators meet this constraint, but their cost per square meter is significantly higher than that of traditional mineral wools.
For lost attics, blowing in mineral wool or cellulose wadding remains the quickest solution to implement. However, for sloping roofs, rigid or semi-rigid panels offer better durability over time.
Renovation budget: underestimated items and safety margins
Structural unforeseen events represent the primary source of budget overruns. A wooden floor that appears healthy on the surface may reveal damaged joists once the covering is removed. A deeply cracked load-bearing wall is only visible after chipping the finish.
We observe that the following items are systematically underestimated in renovation projects:
- Electrical upgrades, which affect almost all homes over thirty years old and consume a significant portion of the secondary work budget
- Floor treatments (screeding, dry screed, sound insulation between floors) whose cost often exceeds that of the final covering
- Ancillary costs: dumpster rentals, site protections, cleaning, and especially additional delays that incur indirect costs (temporary rent, furniture storage)
Planning a safety margin on the total budget is not a precaution; it is a technical necessity. Every interior renovation project must include a reserve for contingencies from the estimation phase, before signing the quotes.
Project reception: the control point that individuals neglect
The contradictory reception marks the transfer of responsibility between the company and the project owner. It triggers legal guarantees (completion, biennial, decennial). Accepting a project without a reception report means waiving a legal lever in case of defects.
The report must precisely list the observed reservations: flatness defects, incomplete joints, equipment not conforming to the quote. Each reservation not lifted within the agreed timeframe may justify a retention on the balance of the contract.
Photographing each room from multiple angles on the day of reception constitutes usable evidence in case of dispute. This step takes an hour; it can prevent months of litigation.
