Screed Drying Time
Under the ideal drying conditions - which is a warm and well ventilated room, Gyvlon screed dries at the rate of 1mm per a day up to a maximum thickness 40mm, screed thickness above 40mm will dry at 0.5mm per a day. For example - say a 50mm thick screed 40mm x 1.0mm per day = 40 days, 10mm x 0.5mm per day = 20days, giving a total drying time of 60 days.
Drying times can be improved by providing good ventilation by opening the windows and doors in good weather, it is also possible to use dehumidifiers and force dry the screed by using the underfloor heating.
Dehumidifiers can be used 7 days after the Gyvlon Screed was laid, It is important that a closed system is employed to ensure that any moisture extracted from the environment during operation is removed whilst the warm air dries the screed. Failure to seal the water collection vessel will result in the moisture being re-circulated delaying drying times.
Force drying of a Gyvlon screed can be accomplished by commissioning of underfloor heating systems in accordance with BS1264: 2001 Part 4 clause 4.4 as early as 7 days after the screed has been placed.
With a raised system water temperature in 4-5ºC increments from ambient to 20-25ºC, maintain for a minimum of 3 days and then gradually increase the temperature again in 4-5ºC increments too maximum operating temperature which should be maintained for a further 4 days (water temperature in the underfloor heating circuit should not exceed 55ºC for Gyvlon calcium sulphate screed), prior to returning to ambient temperature in readiness to receive floor finishes.
Please note that it may be necessary to commission and run the U/F heating system for greater than the 7day commissioning period to enhance the drying. The time that is required for force drying is directly proportional to the age of the screed at the time of commissioning. In all cases it is important to remember that adequate ventilation is required to maintain good drying conditions.
It is recommend that the underfloor heating is commissioned and running prior to the final floor finish is laid.
The screed must be dry before application of the floor finish and failure to follow this procedure prior to the application of subsequent impermeable floor coverings such as vinyl is likely to lead to failure of the floor or delay the project.
Drying the screed by one of the above methods the residual moisture content must be determined using one of the approved test procedures to demonstrate suitability for acceptance of floor finishes (0.5% for impermeable finishes such as vinyl, and tiles and 1.0% for carpets)
The information provided above is given in best faith as a guide to drying of Gyvlon screeds and can be greatly influenced by individual site conditions.
Other Gyvlon features
The screed has a minimal expansion (0.012mm/Mk)
It also has excellent thermal conductivity (2.2W/Mk)
Compressive strength:
after 3 days >15N/mm2after 28days > 30N/mm2
Flexural Strength:
after 3 days > 3N/mm2after 28days > 8N/mm2