Tile adhesive: the role of cement and the C1/C2 classes explained

A tile adhesive is a factory-prepared dry mix: cement, fine sand, fillers and admixtures (redispersible resins, cellulose ethers), to which only water is added at the moment of use. It bonds ceramic tiles, faience, porcelain stoneware or stone onto any stable substrate. Unlike a site-mixed cement mortar, its formulation is calibrated to deliver adhesion, open time and shear strength — performance guaranteed by a standard classification.

A useful clarification up front: Dakhla Aménagement neither manufactures nor sells tile adhesive. We produce the CPJ 45 and CPJ 55 cement that go into those products' formulation. This article shares our reference points on the role of cement in tile adhesive and on choosing a class — because a successful tiling job starts with the right product, even when it does not come from our silos.

The role of cement in the formula

Cement is the binding skeleton of the tile adhesive: as it hydrates, it stiffens the layer and develops the mineral adhesion to the substrate. The cement class influences the final bond strength — which is why high-performance formulations (C2) rest on stronger cements — while redispersible resins bring deformability and adhesion on difficult substrates. Cement quality and consistency matter as much as the rest of the formula: a compliant (NM 10.1.004), fresh and consistent cement is the base of a durable bond.

Understanding classes C1 and C2

European standard EN 12004 ranks tile adhesives by adhesion (measured in MPa after ageing):

• C1 — adhesion ≥ 0.5 MPa: the standard for interior tiling on stable substrates (kitchen faience, bathrooms, wall tiles).
• C2 — adhesion ≥ 1.0 MPa: recommended outdoors, for large formats (beyond roughly 600 × 600 mm), porcelain stoneware, pools and high-traffic areas.
• C2TE — C2 with extended open time: more latitude between spreading and laying, valuable in heat.
• C2TE S1/S2 — deformable: for substrates subject to movement (heated screeds, terraces on pedestals, timber supports).

The application rules that make the difference

Mix respecting the water dosage on the product sheet — about 25 to 30% of powder weight — pouring powder into water, never the reverse. Let the mix mature 5 to 10 minutes, then remix: that maturation develops the admixtures' plasticity. Spread with the notched trowel matched to the tile format and respect the open time: when the surface film starts to dry (the mortar stops "transferring" to your finger), remove and re-spread — laying onto a dry film is the first cause of delamination. Allow 4 to 6 kg per m² depending on trowel and format.

Prices and supply in Morocco

As market order of magnitude, expect 70-90 DH per 25 kg bag for a standard C1, 95-130 DH for a C2 and 140-180 DH for a high-performance C2TE S1/S2. Those ranges vary by brand and region. For the cement that goes into formulations — ours or your suppliers' — CPJ 45 and CPJ 55 are quoted personally through the quote form.