Which tile adhesive do I need?
Three facts settle it: the tile, the location and the substrate. The difference between a floor that lasts and one that lifts after a season is almost entirely in those three — not in the brand, and not in the price.
Pick all three to see the result — or read the full table below.
The full table — required class for every case
On sound cement render. Other substrates — smooth concrete, existing tile, gypsum, timber — add a preparation step before fixing and do not change the required class, except for timber.
| Tile | Interior, dry | Bathroom or kitchen | Balcony or exterior floor | Exterior facade | Pool or water tank | Underfloor heating |
|---|---|---|---|---|---|---|
| Standard ceramic | C1T | C2TE | C2TE | C2TE S1 | C2TE S1 | C2TE S1 |
| Porcelain | C2TE | C2TE | C2TE | C2TE S1 | C2TE S1 | C2TE S1 |
| Large format (60x60 and up) | C2TE | C2TE | C2TE | C2TE S1 | C2TE S1 | C2TE S1 |
| Marble or light natural stone | C2TE | C2TE | C2TE | C2TE S1 | C2TE S1 | C2TE S1 |
| Mosaic | C1T | C2TE | C2TE | C2TE S1 | C2TE S1 | C2TE S1 |
Why these three decide it
The tile decides the bonding mechanism. A tile that absorbs water lets a standard adhesive set against it; porcelain, absorbing under 0.5%, draws in nothing and needs a polymer that grips by adhesion rather than suction.
The location decides the stress: water, heat and movement. A facade expands and contracts every day, underfloor heating with every cycle, a pool is permanently submerged — each demands deformability the standard class does not provide.
The substrate rarely changes the class, but it adds the preparation step without which the best adhesive still fails: smooth concrete needs a rough contact primer, a friable surface needs a penetrating one, and existing tile needs checking for voids before anything else.