Repair of cracked historic screed.

Structure type

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

Detail

Installation of tiles, terracotta or stone flooring on an existing lime screed with non-through hairline cracks.

Application cycle

1. Any existing layer acting as a lightweight insulating screed, with or without building services.
2. Lime screed more than 4 cm thick, bonded or floating, with hairline cracks, even widespread ones, caused by shrinkage, thermal expansion or variations in thickness.
3. Primed or alkali-resistant glass fiber strengthening mesh of 150–160 g/m², laid on a first coat of RALLK Kerasiv Kalce adhesive spread with a notched trowel.
4. RALLK Kerasiv Kalce adhesive covering and fully embedding the mesh, spread with a steel trowel to give a solid, uniform and even base for laying the ceramic, terracotta or stone tiles.
5. Ceramic, terracotta or stone finish covering laid with RALLK Kerasiv Kalce adhesive, indoors or outdoors, 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.