Ammonia Smell in a Newly Renovated House: Where It Comes From and What to Do

The renovation is finished, and the house smells of ammonia — so strongly you cannot sleep in it. This is a common post-works scare, and it is almost always misdiagnosed. Here are the real sources of these emissions, and the method to establish the facts before deciding whether to live in the property.

Real sources of ammonia after building works

• Self-levelling screeds and tile adhesives: their chemical admixtures (accelerators, plasticisers) release ammonia for weeks after installation — the number one cause in floor renovations;
• Epoxy resins: floor coatings, epoxy paints, two-component adhesives — their amine hardeners give off an acrid smell described as ammonia or fish;
• Spray foam insulation badly dosed or not fully cured;
• Confusion with formaldehyde: particle boards, new furniture and wood glues emit a pungent gas often described as ammonia — the remedy is different, and only measurement tells them apart;
• Water-based plasters and paints of poor quality, stored in the cold.

Why measure before deciding

A smell says nothing about concentration. Yet concentration — measured as total VOCs, formaldehyde, ammonia — determines whether the home is habitable, whether a few weeks of ventilation will do, or whether remedial works are required. Our measurements, room by room with calibrated instruments, turn opinions into figures and an evolution curve.

The report that protects your rights

If the works are recent and the contractor still liable, our expertise supports a claim: a building product that emits to the point of making the home uninhabitable is not conforming. The written report (measurements, identified source, recommendations) feeds the claim, the formal notice, or a court-appointed expert procedure if needed.

Free quote before any mission, fast intervention — we know how to handle it when you cannot sleep at home: 04 22 46 06 04 — English spoken.

📅 Mis à jour le 25/09/2026 — Cassini Expertise, expert bâtiment indépendant (06·83·13·40).