Aftercare Information
0 - 48 hours after installation
Immediately after application and until the screed has hardened protect the surface from frost, direct sunlight, draughts and water ingress. The environment should remain sealed for 48 hours and access restricted.
Do not cover the screed. Screedflo should not be cured under polythene.
48 hours to 7 days
Light foot traffic after 48 hours. Normal site traffic and erection of non-load bearing partitions can proceed after 7 days.
After 48 hours good drying conditions should be encouraged. Increase ventilation and encourage favourable air temperatures.
Dehumidifiers and space heaters can be used as early as 7 days after application to assist with drying. Care should be taken to ensure that a closed system is employed to avoid extracted moisture being re-circulated. Avoid water ingress on completed screed and remove any standing water as soon as possible. Screedflo may suffer a temporary loss of strength whilst saturated but this will be regained upon drying.
Screedflo is not a wearing surface and protection from other trades should be considered in highly trafficked areas.
Surface Laitance
All screeds produce laitance to some extent. It is beneficial after a minimum of 7 days to lightly abrade the floor to remove any loose friable laitance. This can sometimes be achieved using a stiff brush instead of sanding. This action does not replace the requirement for good preparation on the part of the flooring contractor. When sanding it is advisable to use a light industrial sander with an integrated vacuum system to help minimise airborne dust.
Floor Finishes
In line with the requirements of the appropriate national standards it is the responsibility of the flooring contractor to ensure that the screed is suitably dry, prepared and given a key to receive the floor coverings.
As a guide the surface of the screed should be mechanically sanded to ensure it is free from loose friable laitance and other extraneous construction debris and contamination which might interfere with the adhesion of the coverings. This could include paint, plaster, mud, mortar and a multitude of other contaminants which may attach to the screed during the normal operation of a building contract.
Drying
The screed should be suitably dry as measured using an approved test method. This can be done using either a flooring hygrometer, a carbide bomb or an oven dried sample in line with the requirements of the relevant British Standards. Screedflo screeds can be dry very quickly after installation. However, as with all screeds, drying rates can be significantly affected by site conditions as well as depth of screed so these need to be carefully managed.
When installed over under floor heating the screed must be put through the commissioning cycle in accordance with BS1264:2001 Part 4 prior to the application of floor finishes.
This also means that force drying can be accomplished and the underfloor heating system can be commissioned as early as 7 days after application, which means a 50mm screed could be dry and ready to receive floor coverings 28 days after installation.
Raise the water temperature in 4-5°C increments from ambient temperature to 20-25°C and maintain for a minimum of 3 days. After this period further raise the temperature in 4-5°C increments per day up to the optimum operating temperature of the system. Note: Water temperature should not exceed 50°C.
Maintain for a further 4 days (typically 7 days if force drying) for a 50mm screed prior to returning to ambient temperature in readiness for floor finishes. Ensure that the UFH system is switched off for a minimum of 48 hours prior to determination of the moisture content using a recognised method. Failure to follow this procedure prior to the application of floor coverings is likely to lead to the failure of the floor finish.
Primers and smoothing compounds
The screed may not always require a smoothing compound but if it does you should, where possible, select one based on calcium sulphate to ensure full compatibility with the screed. If cement based smoothing compounds or tile adhesives must be used the selection of an appropriate primer is important. In either case the screed should be sanded to provide a key and primed using a suitable primer in line with the manufacturers recommendations. Most manufacturers will only guarantee the performance of their own products so we suggest using the same manufacturer for the primer and the smoothing compound or tile adhesive.
For more specific guidance on preparation for floor coverings you should consult your flooring contractor or the relevant sections of the CFA guide to contract flooring.
