Under
Floor
Heating

Fitting wooden floors safely over under floor heating is simple and effective if some basic rules are followed.

Prior to installation Galacroft’s basic site conditions must be met before the floor is installed, these are the same site conditions that we insist on for the installation of all our hardwood floors with a few additions specifically for wooden floors fitted over under floor heating. The basic site conditions are as follows:

• Air relative humidity should be at a stable point between 40-60 %.
• Moisture content of the walls must not exceed 8% Air temperature should be no less than 13 degrees C and the general operating environment should be between 18- 24 degrees C
• All wet trades such as plaster, terrazzo and floor tiling should be completed and dry before wood floors are installed.
• Windows must be glazed and outside doors hung before wood floors are installed.
• New buildings or extensions should be adequately ventilated and heated for at least 10 days before wood floors are installed.
• All radiator and water pipes should be subjected to a water test before installation of wood floors.
• Any sub floor must be smooth and flat to within +/- 3mm over a 3 metre radius.
• Concrete sub floors must be sound and not loose.
• Wooden sub floors must be sound and securely fixed.
• Moisture content of wooden sub floors must be between 8-10 % and within 4% of your hardwood floor to avoid over expansion or contraction.
• Moisture content of concrete screeds must be no greater than 75% relative humidity
• A DPM must be incorporated below any screeded surface.

The additional conditions for wooden floors fitted over under floor heating:

• Hot water under floor heating systems must be fully commissioned and pressure tested prior to fitting of the hardwood floor.
• Any under floor heating system must be calibrated to restrict the surface floor temperature to a maximum of 27 degrees centigrade.
• Under floor heating systems both hot water and electric must have a floor probe to prevent the surface floor temperature from exceeding 27 degrees centigrade.
• The under floor heating system must be turned off during installation and only turned back on after a minimum of 48 hours after the installation is complete.
• Any wooden floor that is to be fitted over under floor heating must be kiln dried to between 6% – 8% according to BS 8201:2011.

Site conditions at the time of fitting and the environment in which the floor is kept post installation are critical for a successful wooden floor installation, this applies whether you have under floor heating or not.