Tile installation after removing the old flooring.

Structure type

Existing sand-cement screed, possibly with localized or widespread non-through hairline cracks.

Detail

Adhesive residues less than 5 mm thick. Tile installation on an existing screed with non-through hairline cracks.

Application cycle

1. Sand-cement screed more than 4 cm thick, bonded or floating, with or without an impact sound separating membrane, with hairline cracks (even widespread ones) caused by shrinkage, thermal expansion or variations in thickness. After removing the existing covering, its cleanliness and surface strength have been checked, along with any tile adhesive residues less than 5 mm thick.
2. Leveling and/or smoothing skim coat for unevenness up to 5 mm thick caused by stubborn adhesive residues left after removing the old ceramic or stone covering, carried out with RALLK Kerasiv K Flex spread in one or two coats with a steel trowel.
3. Primed or alkali-resistant glass fiber strengthening mesh of 150–160 g/m², laid wet-on-wet on RALLK Kerasiv K Flex adhesive.
4. RALLK Kerasiv K Flex adhesive covering and fully embedding the mesh, spread with a steel trowel to give a solid, uniform and even base for laying the ceramic or stone tiles.
5. Ceramic or stone finish covering laid with RALLK Kerasiv K Flex adhesive for indoor or outdoor ceramic or stone tiles in small or large formats.

Additional information

1. After removing the old covering, check the soundness of the existing screed and of any adhesive residues, and make sure the substrate is clean, before starting any work.
2. Check that adhesive residues, and surface irregularities in general, are less than 5 mm thick.
3. Check that the cracks do not run right through the screed, breaking its continuity. If they do, they must be bonded with a suitable adhesive.
4. Check that the cracks are stable and no longer developing, and/or that they are not caused by stresses or loads still acting on the screed and making it move cyclically.
5. See the individual product data sheets for application methods and precautions.