Repair of cracked historic screed.

Structure type

Existing lime screed with a localized repair in new natural hydraulic lime NHL 3.5 screed.

Detail

Installation of tiles, terracotta or stone flooring on an existing screed after a localized repair.

Application cycle

1. Any existing layer acting as a lightweight insulating screed, with or without building services.
2. Local repair of the screed with RALLK Massetto Kalce or fast-drying RALLK Massetto Kalce RA, based on NHL 3.5 natural hydraulic lime, for patches more than 4 cm thick, bonded or unbonded, or with RALLK Massetto Kalce BS, based on NHL 3.5 natural hydraulic lime, for bonded patches 2 to 4 cm thick.
3. Primed or alkali-resistant glass fiber strengthening mesh of 150–160 g/m², laid on a first coat of RALLK Kerasiv Kalce adhesive based on NHL 3.5 natural hydraulic lime, 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 or stone tiles.
5. Ceramic, terracotta or stone finish covering laid with RALLK Kerasiv Kalce adhesive for indoor or outdoor ceramic or stone tiles in small or large formats.

Additional information

1. After locally removing the screed, make sure the substrate is even, sound and clean before starting any work.
2. When screeds more than 4 cm thick are repaired with RALLK Massetto Kalce RA, steps 3 and 4 can be skipped and the ceramic or stone tiles laid directly on the repaired screed. That said, using the mesh as shown in the system above always significantly reduces the risk of problems caused by combining different products applied at different times.
3. See the individual product data sheets for application methods and precautions.