Underfloor Heating Preparation Guidance

It is becoming increasingly common to come across floors with underfloor heating systems incorporated. It is important to note the following points and check the underfloor heating before you begin work.

Where warm water underfloor heating systems are incorporated, they must have been fully commissioned and brought up to their maximum temperature, and ideally switched off 48 hours before the application of UltraFloor products. It is important to establish that the commissioning of the system has been carried out, consult the underfloor heating manufacturer for confirmation. In the absence of other heat sources, the underfloor heating may be set to ‘cutback’ position to achieve an air temperature of 15°C. Any expansion or movement joints must be carried through to the finished floor surface.

The cables of radiant electrical underfloor heating systems must be secured to a sound, strong mechanically fixed cement faced backer board. UltraFloor products may also be used where electrical underfloor heating is used over cementitious or calcium sulphate subfloors. In all cases our smoothing underlayments must be applied at a minimum thickness of 5mm above the cables for resilient, textile and timber applications and a minimum of 3mm for applications of stone, ceramic or porcelain products.

Warm water systems fixed within pre-formed insulation panels must be mechanically fixed to the existing subfloor/substrate these must be sound and solid with no movement. The panels should be primed depending on the porosity and type. In all cases our smoothing underlayments must be applied at a minimum thickness of 5mm above the cables for resilient, textile and timber applications and a minimum of 3mm for applications of stone, ceramic or porcelain products.

There is no requirement to commission warm water systems fixed within pre-formed insulation panels or radiant electrical underfloor heating systems before the application of UltraFloor products. These systems should be commissioned 7 days after the UltraFloor products have been applied. To commission these systems the heating should be increased 5°C per day from ambient until the maximum operating temperature has been reached, and then decreased back down again by 5°C per day.

The Instarmac CPD – Specifying Tiling to Underfloor Heating Systems – will provide you with an understanding of the benefits of heated tiles and the types of system available.  It will also cover key design and specification considerations and product choices for tiling to underfloor heating and selecting appropriate materials.  It will teach you how to confidently specify typical tiling system build-ups for underfloor heating, and you should also understand the importance of warranties and confidence in complete performance systems. Please visit The Instarmac Training Academy or call 01827 254402 for more information.

Pre-smoothing of Subfloors/Substrates

Where there is an absence of a damp proof course and provided there is no risk of hydrostatic pressure, pre-smoothing can be carried out. UltraFloor Level IT Two, UltraFloor Level IT Bond, UltraFloor Level IT Top and UltraFloor Level IT Base are all suitable for pre-smoothing use, please refer to their respective datasheets for further guidance.

Wear Surface/Surface Finish

When installing a wear surface ensure that the subfloor/substrates has been tested for moisture, any contamination or laitance has been removed, prime if required and check for underfloor heating. Both UltraFloor Level IT Top and UltraFloor Level IT Super Flex 30 may be used as a finished wear surface. Please refer to their respective datasheets for further guidance