What to consider when considering underfloor heating

By Tal | 2013-07-31

Update 2020-01-31

Underfloor heating is a heating solution many home owners and commercial customers are opting for as it is an economical method to heat the floor and ambient temperature of the room.

It is important to select the correct underlayment and to follow the materials and methods specification closely when applying the compound to ensure that the heating system functions at its best.

Underfloor heating systems go hand-in-hand with constant temperature variations caused by the heating cycle. These temperature changes affect the expansion and contraction of the substrate.

To ensure that the underlayment can withstand these temperature shifts and prevent it from cracking, it is important to select the correct cementitious screed and to modify the compound with an additive to provide flexibility to the installation. In addition, the underlayment installation has to adhere to set specifications:

  • TAL Superscreed is a high strength, rapid set, non-shrink cementitious screed that produces a smooth hard wearing surface suitable for fixing all floor coverings. It is especially suitable for use as a protective barrier over ceramic tile heating elements, when mixed with TAL Screedbinder.
  • TAL Screedbinder is a latex additive that is designed to improve the bond strength and flexibility of the underlayment when used as a total water replacement in the TAL Superscreed mix.
  • Apply the levelling compound to the required thickness to completely cover the heating elements and or wires. Often only a couple of millimetres are required. TAL Superscreed can be applied up to 12mm in a single layer.


When tiling in areas with underfloor heating, it is imperative to use a latex-modified adhesive and grout system to allow for the anticipated thermal expansion and contraction.  

TAL Bond should be used as a total water replacement in the adhesive and grout mix, and tile panel movement joints should be located at maximum 3 metre centres in both directions, as well as around the perimeter of the floor, or alternatively TAL Bond Powder can be added to the mixing water. Tile panel movement joints should be located at maximum 3 metre centres in both directions, as well as around the perimeter of the floor.

The right choice of underlayment and correct installation method will result in a floor that acts as an efficient heat conductor and therefore improves the energy efficiency of the heating system.

The use of latex-modified adhesive and grout systems will result in a flexible tile installation that can withstand the constant expansion and contraction associated with underfloor heating.

If in doubt, contact the TAL Technical Advice Centre for more information.




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