On a renovation site, the real problem is often discovered only once the wall is opened. A crack in the facade can hide a structural defect, and a creaking floor may reveal an issue with moisture underneath. Building or renovating a house requires fewer grand ideas than timely technical decisions made in the correct order.
Gas phase-out and MaPrimeRénov’: what’s been blocking projects since September 2026
Since September 1, 2026, the MaPrimeRénov’ “by gesture” pathway no longer separately finances insulation, windows, ventilation, or wood stoves in mainland France. Decree No. 2026-822 of August 25, 2026, has refocused the program on large-scale renovation.
In practical terms, retaining gas heating can block access to MaPrimeRénov’ for large-scale renovations. The work must include a decarbonized heating and hot water system (heat pump, connection to a district heating network). Many homeowners who planned to renovate in stages now face a different financial decision.
Other programs can still be mobilized to cover part of the cost: energy savings certificates (CEE), eco-PTZ, and a VAT rate of 5.5%. For those preparing a renovation project, it is advisable to visit the Batiwiz home site to compare technical solutions before finalizing a work plan.
The old reflex of “we start with insulation, and we’ll see about heating later” remains technically possible, but it no longer automatically triggers public aid. Comparing the cost of a comprehensive renovation with the remaining aids becomes the first real step of the project.
Order of work in renovation: costly mistakes
A poorly sequenced renovation site generates rework. Installing a floor covering before addressing a moisture issue in the slab guarantees a second project within two years. Installing a double-flow ventilation system after closing the partitions requires reopening duct passages.
Sequence according to the logic of the building, not according to the monthly budget
There is a tendency to prioritize what is visible (painting, kitchen, bathroom) and to postpone what is not visible (waterproofing, ventilation, electrical network). However, the building imposes a precise order:
- First, the enclosure and the roof: roofing, facade, exterior joinery. As long as the envelope is not watertight, all interior work is exposed.
- Next, the networks: electricity, plumbing, ventilation. These elements run through the walls and floors, so they come before the finishes.
- Insulation and heating should follow, as the sizing of the heat pump or heating system directly depends on the level of insulation achieved.
- Finishes last: partitioning, coverings, interior layout.
When renovating in phases over several months, each phase must leave the site in a stable condition. An insulated wall that is not protected by a cladding will deteriorate. An electrical conduit installed without a junction box remains a point of vulnerability.
New construction and RE2020: anticipate constraints from the planning stage
For a new house, RE2020 imposes requirements on the energy performance and carbon footprint of the building. You can no longer draw up a plan and then “add” insulation later. The choice of structural materials (wood, brick, low-carbon concrete) directly affects regulatory compliance.
Bio-based materials and thermal inertia
Bio-based materials (wood frame, wood fiber insulation, cellulose wadding) have a good carbon balance at construction. However, feedback varies on summer comfort in regions with high thermal amplitude: the thermal inertia of a wood frame is lower than that of a monolithic brick wall or cellular concrete.
The choice of structural material impacts comfort throughout the building’s lifespan. A load-bearing frame cannot be changed. Before validating a construction system, the project must be compared to local climatic conditions, not just the theoretical carbon balance.
Land and soil study: do not skip this step
The geotechnical study (G2 soil study) determines the type of foundations needed. On clayey soil, traditional shallow foundations risk cracking the structure during the first dry spell. The cost of a soil study represents a marginal fraction of the overall construction budget, but its absence can lead to serious structural issues.
Facade and natural light: two underestimated levers in renovation
Facade renovation is often associated with aesthetic improvement. In reality, this is the time to address external thermal insulation (ITE), reposition or enlarge openings, and rethink natural light intake in living spaces.
Enlarging an existing window costs less than creating a new one when the lintel is already sized for a wider opening. You gain brightness without touching the load-bearing structure, provided you check the facade plan with an architect or a design office.
For blind rooms (hallways, interior bathrooms), natural light conduits (tubular skylights) offer an alternative to traditional roof windows, especially when the roof configuration does not allow for a Velux.
- ITE eliminates thermal bridges at wall-floor junctions, which interior insulation does not correct.
- A facade renovation coupled with ITE allows for shared scaffolding and reduces the overall cost of the project.
- The choice of finishing render (mineral, silicone, siloxane) depends on the facade’s exposure and the type of support.
Renovating the facade without addressing insulation is like repainting a wall that leaks. Both interventions benefit from being carried out together, both for thermal results and for the renovation budget.
Every construction or renovation project relies on technical decisions made early on, often before the first strike of the hammer. The regulatory framework of 2026 makes these decisions more constraining but also more structuring: one can no longer improvise the order of work or postpone energy choices. It is better to spend time on this in advance than to pay for rework on site.
