7 mistakes to avoid on a major renovation project

A major renovation touches the structure of the building: load-bearing walls, floors, roof, foundations. That is precisely what sets it apart from a simple refresh, and why a handful of early mistakes end up costing so much, in both budget and delays. Here are the seven mistakes we see come up most often on renovation sites between Bormes-les-Mimosas, Le Lavandou and Hyères.

1. Underestimating the existing structure

A facade in good condition or a freshly painted room can hide tired foundations, a weakened floor, or a load-bearing wall that has been cracked for years. Starting the project without a structural survey means risking a major discovery once work is already under way, exactly when it costs the most to fix.

2. Skipping the crack and damp diagnosis

Not all cracks are equal. Some are purely cosmetic, others point to structural movement or a foundation issue. The same goes for rising damp, common in older buildings along the Var coastline. A proper diagnosis before work begins avoids renovating over a problem that will simply resurface, usually worse than before.

3. Hiring multiple contractors without coordination

On a major renovation, structural work, utilities and finishes have to follow a precise order. Bringing in several separate contractors without one person coordinating the schedule almost always leads to the same outcome: delays stack up, accountability gets blurry if something goes wrong, and no one truly owns the day-to-day supervision.

4. Ignoring the paperwork

Depending on the scope of work, a prior declaration or a building permit may be required, particularly when the structure, the facade or the habitable floor area changes. Starting work without these approvals risks a stop-work order midway through, or complications when the property is later sold.

5. Choosing a contractor on price alone

An unusually low quote usually hides one of three things: less detailed work, lower-grade materials, or a deliberate underestimate that resurfaces as change orders once the site is under way. A clear, itemised quote is what lets you compare like for like.

6. Leaving no budget margin

On older buildings in particular, part of the work stays invisible until the site actually opens up. Setting aside a margin of around 10 to 15 percent of the total budget absorbs an unexpected discovery without forcing a rushed choice between finishing the job and sticking to the original budget.

7. Going without a single point of contact

A major renovation runs for several weeks, sometimes several months. Having one dedicated manager, reachable and regularly on site, is often what separates a project that stays under control from one that runs away from you.

A well-prepared major renovation is, in the vast majority of cases, a project that stays under control. The difference comes down less to luck than to how seriously the initial diagnosis is taken, and to choosing someone who follows the site from day one through to handover.