A clay soil that swells after three weeks of rain, a soil survey revealing a water table two metres below the surface: a construction project doesn’t start with glossy plans, but with the conditions imposed by the ground. Construction work on a property development follows a technical sequence in which each phase determines the next, and a shift in the schedule can change which materials are permitted.
RE2020 and the building permit submission date: the timing trap that can change your project
People often assume that regulations apply when construction begins. In reality, the date the building permit application is submitted determines which RE2020 requirements apply. Since 2025, carbon requirements for construction have become stricter, with a new threshold scheduled for 2028.
In practical terms, a project whose permit application is submitted just a few weeks too late may fall under a stricter threshold. This directly affects the choice of structural materials, insulation, heating system and even summer comfort. Before finalising the plans, it’s worth asking the builder or architect to check the consequences of a change to the submission schedule.
RE2020 is about more than heating. It takes into account the carbon impact of materials and equipment over the building’s entire life cycle.
A conventional concrete block wall and a timber-frame wall do not have the same carbon footprint, and this factor can influence design decisions well before work begins. Whether you’re commissioning work from Zlati Constructions or another established professional, this regulatory check is part of the project’s initial planning.
Soil surveys and site constraints: what determines your construction budget
A geotechnical survey (a G2 survey carried out during the pre-design phase) is not a mere formality. It determines the type of foundations required, and the cost difference between shallow and deep foundations can account for a significant share of the total budget.
Building on clay soil requires foundations designed to withstand shrink-swell movement, which also affects the design of floor slabs and buried utility networks. The local planning scheme (PLU), meanwhile, sets rules on building placement, height and, in some cases, façade materials. You should have both documents—the soil survey and the planning regulations—before drawing up any plans.
What to check before buying a plot
- The soil’s classification for clay shrink-swell risk, which can be checked on the Géorisques website and may require specific construction measures
- The PLU zoning and any easements (utility corridors, flood zones, protected areas around historic monuments) that limit the plot’s actual development potential
- Existing or required utility connections: water, electricity and public or private wastewater systems. Costs can vary considerably depending on the distance to public networks
When it comes to land, the ZAN (zero net land take) framework is making plots harder to access in some municipalities. A July 2025 decision by the Conseil d’État confirms that the consumption of natural, agricultural and forest land is measured according to its actual use, not solely its zoning under the planning document. A plot classified as buildable may therefore still present difficulties if it is currently used for agriculture or remains in a natural state.
Contracts and stage payments: managing financing step by step
The individual house construction contract (CCMI) remains the most protective legal framework for private individuals. It sets a fixed, final price, a delivery deadline and late-delivery penalties. However, stage payments are tied to the actual progress of the work, not an arbitrary schedule.
Under a CCMI, stage payments are regulated by law:
- Work commencing triggers the first payment request, capped at a percentage of the agreed price
- Completion of the foundations, the building being made watertight and the building being made airtight each correspond to a stage at which funds can be released
- The balance is not due until handover, when the client checks that the work complies with the contract and plans
This system protects the project’s financing: you don’t pay for work that hasn’t been completed. Even so, your financing plan with the bank needs to match this schedule. A mismatch between the builder’s payment requests and the bank’s release of funds can lead to interim interest charges that increase the total cost.
Compliance and handover: the two certificates you must not forget
Regulatory compliance for a new build is checked at two separate stages, not just one. The first certificate is required when the building permit application is submitted, confirming that the project meets the applicable thermal and environmental requirements.
The second is issued when the work is complete. It is attached to the DAACT (declaration confirming completion and compliance of the work), which is submitted to the local council. Between these two stages, any design change made during construction (such as changing the ventilation system or replacing one insulation material with another) can jeopardise compliance. Technical monitoring throughout construction helps ensure final compliance.
Handover: a legal act, not just a walk-through
Handover is when the client accepts the work, with or without reservations. It triggers the statutory warranties: the one-year warranty for defects, the two-year warranty for equipment and the ten-year structural warranty. Recording any reservations in writing in the handover report is not optional; it is essential to protecting your rights.
A successful property project depends less on a generic checklist than on the ability to anticipate the constraints specific to each plot, municipality and regulatory timetable. Submitting the permit at the right time, surveying the soil before buying and reading the contract before signing: these decisions made before construction begins determine the quality and final cost of the build.
