Repair of cracked screed.

Structure type

Existing sand-cement screed with non-through hairline cracks, even widespread ones.

Detail

Tile installation on a 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.
2. RALLK Kerasiv K Flex adhesive spread with a notched trowel over the whole screed.
3. Primed or alkali-resistant glass fiber strengthening mesh of 150–160 g/m², laid wet-on-wet on RALLK Kerasiv K Flex.
4. RALLK Kerasiv K Flex adhesive applied wet-on-wet to cover and fully embed 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. If the old covering is removed, make sure the substrate is even, sound and clean before starting any work.
2. 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.
3. 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.
4. See the individual product data sheets for application methods and precautions.