Polyplumb Underfloor Heating - Floor Coverings

Floor heating systems will work efficiently under any floor covering, as long as it is well insulated underneath. However, each covering has different thermal conduction properties, and harder surfaces offer better conductivity, and, therefore, better heat output rates. The following notes provide some guidance on each type of covering.

Stone and Ceramic Tiles, Marble or Flagstones

Suitable for all Polyplumb floor systems - These types of floor finishes are usually cold underfoot. However, with floor heating they are transformed into warm comfortable surfaces.

Each of these finishes is essentially brittle and it is imperative that the design of the supporting floor structure is stable and rigid to prevent cracking. It is recommended that flexible adhesives and grout be used.

Carpets and Underlays

Suitable for all Polyplumb floor systems - The nature and thickness of the carpet underlay is fundamental in determining good heat transfer.

Most underlays are sponge types that have waffle pattern moulded into their underside, and allow good heat transfer.

The carpet underlays to be avoided are those such as felt and rubber crumb type. If these are used, they can seriously reduce the effectiveness of a floor heating system, as they insulate the floor surface and prevent heat transfer.

The TOG value of carpets and underlays should be available from the respective manufacturer.

The maximum TOG value of underlay should be approximately 0·5.
The maximum TOG value of carpet should be approximately 1·0 to 1·5.

Laminate

Suitable for all Polyplumb floor systems - Laminate flooring should be laid on roll type floor levelling, rather
than the rigid panel type.

Movement that occurs must be accommodated by an expansion gap around the floor deck.

Timber

Suitable for Polyplumb solid floor and suspended floor systems - Concerns regarding the effect of heat on a timber floor are misplaced, and the more important issue is the floor moisture content.

Timber floors should be laid at a moisture content of 10-11%, which when heated will reduce to 8-9%, and cause a very small amount of shrinkage.

The floor will re-absorb some moisture when the heating is not operating and the moisture content will increase to 12-13%.

Vinyl

Suitable for all Polyplumb floor systems - sheet vinyl is sensitive to long term exposure to heat.

There are two categories of vinyl; one is limited to constant temperatures of around 26°C and the other to 30°C. Check the floor surface temperature for compatibility with vinyl flooring.

If unsure contact the Polyplumb hotline or the vinyl floor manufacturer.