French regulatory guidance
France: CSTB Guidance, Renovation, Flowing Screeds and Wet-Area Systems
Navigate French CSTB technical guidance for renovation substrates, flowing screeds, waterproofing beneath finishes and systems outside traditional NF DTU scope.
Why additional French documents exist
NF DTU documents do not cover every modern product or substrate. CSTB specifications, technical assessments and system documents define conditions for particular solutions.
Identify the exact product, current document and project use; do not apply one system’s detail to another.
Renovation over existing finishes
Existing tiles or stone require checks for adhesion, cracks, contamination, flatness and movement. Weak layers must be removed; cleaning and primers follow the approved system.
Covering a defect does not stabilise the substrate.
Flowing screeds
Calcium sulphate and cement-based flowing screeds have different preparation, moisture and heating requirements. Surface laitance and residual moisture must be managed according to the screed and finish system.
Record commissioning of heated floors and measurement results.
| Situation | Required evidence |
|---|---|
| Existing finish | Soundness, cleaning and primer compatibility |
| Flowing screed | Type, moisture, sanding and heating record |
| Wet-area membrane | System approval and continuous details |
| Large-format stone | Scope, flatness and adhesive method |
| Crack treatment | Movement diagnosis and approved solution |
| Non-standard build-up | Technical assessment and clear responsibility |
SPEC and wet-area protection
French SPEC systems protect defined water-exposed walls and floors beneath finishes. They are not interchangeable with structural waterproofing or pool systems.
Corners, drains, penetrations and thresholds must use the complete documented detail.
International project coordination
These documents are specific to work in France. Translate requirements for international stakeholders but retain official French references and editions in the contract file.
Use qualified French designers and contractors to confirm scope and responsibility.
Need advice for a real project?
Marble Import supports international homeowners, architects and interior designers with stone selection, samples, technical feasibility and coordination of high-end stonework in France and across Europe.