Terrace leaking into living room in Fréjus: failed waterproofing

You are in your living room in Fréjus, and suddenly, a damp patch appears on the ceiling. Water is seeping through your terrace. The DTU 43.1 (standard for waterproofing flat roofs) requires a minimum slope of 1.5% to drain water. If your terrace is accessible, it must be waterproofed according to DTU 43.3. Concretely, a crack in the waterproofing membrane is enough for water to infiltrate and run into your living room. Don’t overcomplicate it: the problem very likely lies in the waterproofing, and you need to act fast.

Identify the source of the leak: simple water test

First, locate the leak. Close all water access points on the terrace. Using a garden hose, wet a 1 m² area for 15 minutes, then observe the interior. Move progressively to target the area. This simple method, recommended by experts, allows you to pinpoint the exact spot without tearing everything up. Do it in dry weather. In Fréjus, beware of heavy Mediterranean rains: it’s tempting to wait for a downpour, but the hose test is more reliable.

Check the condition of the waterproofing: what to look for?

On your terrace, inspect the surface. Look for blisters, cracks, areas where the covering is lifting. Singular points – edges, expansion joints, drain outlets – are the most vulnerable. If you see deterioration, the membrane has aged. In the PACA region, UV exposure is intense. Standard bituminous waterproofing lasts 10 to 15 years. If your terrace is over 15 years old, replacement is likely necessary. Don’t settle for simple patching: it hides the problem but doesn’t solve it.

Hiring a professional: why it’s essential

Frankly, repairing waterproofing yourself is risky. DTU 43.1 requires specific skills: substrate preparation, primer, welding of strips. A mistake in installation leads to recurring leaks. A qualified waterproofing contractor will know how to diagnose and propose a durable solution. In Fréjus, insist on a craftsman certified Qualibat or holding the NF standard. Ask for several detailed quotes. Compare proposed techniques: liquid resin, bituminous membrane, or PVC. Each solution has its advantages. The cost varies, but your peace of mind is priceless.

Act quickly to avoid structural damage

Don’t let humidity settle. Infiltrating water can cause corrosion of metal reinforcements in concrete. In the long run, the floor structure is threatened. If you notice cracks in the concrete, consult a structural engineer. Damage can be irreversible. In the Var, ambient humidity accelerates disorders. While waiting for repair, protect your living room: move furniture, dry the area, ventilate. The longer you wait, the higher the bill.

Recourse and guarantees

If your terrace was built recently, you are covered by the ten-year guarantee (Article 1792 of the Civil Code). It applies to damage that compromises the solidity of the structure or renders it unfit for its purpose. Infiltrations in the living room fall within this scope. Contact your insurer and the company that carried out the work. If you are the owner of a unit in a condominium, the terrace may be considered a common area. In that case, the syndic must act. In Fréjus, many such cases are handled each year. Don’t hesitate to be accompanied by an independent expert like me to assess liability.

Questions fréquentes

How to fix a leaking terrace into living room?

First, identify the source of the leak, often failed waterproofing. You'll need to remove the terrace covering, repair or replace the waterproofing membrane, and ensure proper drainage. Consult a professional for a durable fix.

What causes terrace leaks into the room below?

Common causes include deteriorated waterproofing membranes, cracks in the terrace slab, or poor installation around drains and edges. Water then seeps through to the living space below.

How much does it cost to repair a leaking terrace?

Costs vary widely based on the extent of damage and materials. On average, expect to pay between €500 and €2,500 for repairs, but extensive work can cost more. Get quotes from multiple contractors.

📅 Mis à jour le 23/09/2026 — Cassini Expertise, expert bâtiment indépendant (06·83·13·40).