First heat-up of underfloor heating

The screed has to cure, and the first heat-up has to be gradual. Heating too fast can crack it.

Before the screed

• Pressure test: the system is tested under pressure and kept under pressure while the screed is laid, so any leak shows at once.
• Edge insulation strip along all walls, movement joints in doorways and between zones controlled separately.

When it can be switched on

Under EN 1264-4 cement screed can usually be heated no sooner than 21 days after laying, calcium sulphate (anhydrite) screed after 7 days. The screed maker gives the exact time.

How to heat it up

This functional heating checks the system but does not fully dry the screed. Before wood or tiles are laid, extra drying and a moisture test are often needed.

Afterwards

• The loop flows are set on the flow meters so all rooms warm evenly.
• Change the temperature slowly, especially under wood floors.