In just thirty years the UK building industry has seen the use of underfloor heating systems evolve from a non-standard, specialist application, to what we all now consider to be the norm. Over three quarters of new commercial buildings now feature underfloor heating, and the advent of air and ground heat sources has led to a steep increase in its selection in housing and domestic settings. But even after three decades, are we ready for change? At JH Flooring Consultancy, we still see more major failures with Vinyl, PVC and Safety Flooring associated with non-compliance with manufacturers guidelines when it comes to underfloor heating than any other root cause. And with the majority of UK manufacturers now agreeing, and conforming to the UK Resilient Flooring Manufacturers Association guidelines, as well as the instructions issued by the European Resilient Flooring Manufacturers' Institute - Home - European Resilient Flooring Manufacturers' Institute (erfmi.com) , things actually couldn't be simpler.
Whilst we would always recommend following the manufacturers instructions when it comes to underfloor heating, the following eight-point plan broadly outlines the essential steps that should be taken to ensure the successful installation of your Vinyl, PVC or Safety Flooring.
- Step 1 - The underfloor heating system should be installed and fully commissioned before proceeding. We recommend getting written confirmation of this.
- Step 2 - Prior to switching on the underfloor heating, the screed should be fully cured and tested for dryness. When applying Vinyl, PVC or Safety Flooring over cementitious screeds, this typically means 75% RH or below, but it is worth getting specific advice when using Gypsum or Anhydrite Screeds, or for other types of floor finishes, especially hardwood.
- Step 3 - The screed containing the underfloor heating system should then be heated in increments of 5°C per day to 15°C, then 1°C thereafter up to it's operating temperature. This should then be maintained for a minimum of seven days before allowing the screed to cool to room temperature, or 15°C, whichever is the warmer.
- Step 4 - Switch the underfloor heating off 48 hours before installation of floorcoverings.
- Step 5 - In cooler months, if the room temperature falls below 18°C, install suitable temporary heating to ensure that a minimum 18°C is met.
- Step 6 - Complete the flooring installation.
- Step 7 - Do not switch the underfloor heating back on until 48 hours after the flooring installation has been completed, ensuring that the minimum 18°C is maintained at all times.
- Step 8 - Switch the underfloor heating back on by increments of 5°C per day to 15°C, then 1°C thereafter until the desired operating temperature is reached. Do not exceed a maximum temperature of 27°C at the point where the screed meets the floorcovering.
The most common failures in the floorcovering resulting in non-adherence to these guidelines include debonding, bubbling, discolouring and shrinkage.
Whilst the above guidelines are designed to give a broad and unified understanding of the steps that should be taken when installing resilient flooring over underfloor heating, we recommend checking the manufacturers guidelines prior to proceeding. Please see below links to instructions for installation over underfloor heating for some of the major UK vinyl flooring manufacturers and suppliers.
Altro Floors - Altro Flooring And Underfloor Heating Installation Guide | Altro
Forbo Flooring - Working with underfloor heating | Forbo Eurocol Nederland B.V.
Polyflor Ltd - Installation | Polyflor Vinyl Flooring
Tarkett - ID_EN_Installation_Instructions.pdf (tarkett.com)
Gerflor - gerflor-installation-guidelines-underfloor-heating-tis-nb4.pdf