Post Installation Guide Lines for Underfloor Heating
It is important to understand the post installation process in order to achieve the smooth level results desired. Lafarge liquid/flowing screed is a flowing pumpable calcium sulphate based screed that’s suitable for applications of all types of sub floor, underfloor and floating floor heating.
1) Keep the environment sealed
Following installation, the environment must remain sealed for 2 days. The screed should be protected from direct sunlight and frost during this time. After this period drying conditions should be maintained, increase ventilation, and if possible increase room temperature to minimise drying time.
Do not cover with polythene
Storage of materials on the screed surface, accidental exposure to water, humid or cold environments will all delay drying.
2) Wait 7 days before force drying
When installed over underfloor heating and cooling systems the screed must be heated prior to application of floor finishes. This can commence as early as 7 days after installation, commissioning of underfloor heating should be carried out in accordance with BS1264:2001 Part 4 Clause 4.4 and in line with the manufacturers recommendations, heating should be gradual, in 3—5oC increments and at no time should the water or cable temperature exceed 50oC. The system should be switched off for a minimum of 48 hours (2 days) prior to determination of the moisture content and installation of floor finishes.
3) Prior To Installation
Prior to installation of floor coverings, the moisture content of the screed should be determined using the hair hygrometer in accordance with BS8203. The Contract Flooring Association (CFA) and the Tile Association have recommendations relating to installation of floor coverings on calcium sulphate screeds. These bodies should be consulted for further information. The surface of the screed should be free from dust, skin or other contaminants and should be sealed with an appropriate primer prior to the application of subsequent adhesives or levelling compounds (consult the manufacturer for suitable products and recommendations for installation).