The general practice for curing of Portland cement mortar screeds is to lay tight fitting polythene sheets to form a surface barrier, slowing the rate of moisture loss. The slow loss of water from the surface of fresh concrete or mortar reduces the incidence of cracking and crazing of exposed surfaces, facilitates efficient cement hydration, improves surface hardening and reduces dusting.
Spray applied curing membrane systems may be used when early overcoating or overlaying of the mortar is to be carried out. This type of system is used in place of polythene and is easily spray applied to surfaces immediately after finishing and will not damage the surface finish.
Curing Membranes are supplied ready to use; no dilution is required and should be applied by low pressure spray to the surface of the newly placed mortar or concrete. They membrane should be applied as a fine mist on to the surface, and suitable equipment is best determined by site trials.
The entire surface of the mortar or concrete should be covered as soon as possible after placing to provide maximum benefits. The spray nozzle should be held 30–50cm from the surface and the pressure maintained to provide a fine mist spray. Care should be taken to produce a continuous film and to ensure that the correct coverage rate is maintained. Care must be taken to avoid over use as exceeding the recommended application rate may affect early overlaying/coating depending on the floor finish involved.
- Reduces moisture loss
- Reduces risk of cracking and crazing
- Easy to apply
- Improves surface hardening
- Reduces dusting