Renovating a concrete pool: cracks, coating, liner

The signs are unmistakable:

• Visible cracks on the walls or floor, fine or open.
• Coating that is peeling, blistering, or coming off in patches underfoot.
• Water loss greater than normal evaporation (more than 3 mm per day).
• Black or rusty stains that return despite brushing — often structural reinforcements starting to work.

A single one of these signs doesn't mean 'major work'. But it deserves a professional look, because a crack treated early costs ten times less than one that migrates.

This is THE question that determines everything else.

A coating crack stays on the surface: it doesn't move and is mainly unsightly. It is addressed during the coating renewal.

A structural crack goes through the concrete. It can move with the seasons, let water pass, and worsen. In the Var, clay soils that swell and shrink with drought are often the cause. It requires specific treatment: opening, packing, sometimes stapling, before any finishing.

This is exactly what we check during the technical visit: we never apply a finish to a diseased structure.

Once the structure is sound, we choose the basin's new skin:

• Coating (marbrex, silico-marble): the traditional result, smooth and luminous. Good lifespan, easy maintenance, but requires careful application.
• Liner: the fastest and most economical solution. A custom-made membrane installed in a few days. Perfect for a sound basin whose appearance you want to refresh.
• Reinforced covering (reinforced PVC): thicker and more resistant than a liner, welded on site. The right compromise for a basin that has experienced leaks.

The right choice depends on your basin, your budget, and the desired look — this is the core of the discussion during the technical visit.

A typical Pool-Hero project:

1. Technical visit and diagnostic of the structure (link to our pool renovation page for details). 2. Fixed quote, item by item — nothing starts without your written approval. 3. Draining and preparation: stripping, crack repairs, leveling. 4. Application of the chosen finish, refilling, and rebalancing.

Count on generally a few days to two weeks depending on the scale. The best time in the Var: from October to March, when the pool is not in use and temperatures are mild for coatings.

• Redoing a coating on a cracked structure: the crack will reappear within the year, guaranteed.
• Choosing a liner to hide a leak that hasn't been localized: water will pass behind it.
• Draining without professional advice during a wet period: on clay soil, water pressure can lift the concrete shell. Yes, it happens.
• Launching in May to be ready in June: it's the rush, lead times get longer. Plan ahead in the autumn.