Underlay TOG rating

Duralay Durafit 650 TOG rating and underfloor heating

The published TOG and datasheet figures for Duralay Durafit 650, and what it means over a heated floor.

1.1TOG

Suitable for UFH

Leaves 1.4 TOG of the combined budget for the carpet on top before the 2.5 TOG limit is reached.

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Duralay Durafit 650 is rated 1.1 TOG and is suitable for underfloor heating. It leaves 2.4 TOG of the combined budget for the carpet on top before the 2.5 TOG limit is reached.

Published datasheet

Manufacturer	Interfloor (Duralay)
TOG rating	1.1 TOG
Thickness	6.5 mm
Density	415 kg/m3
Sound	29 dB impact reduction
Underfloor heating	Suitable

Durafit 650 is a double-stick crumb-rubber contract underlay rated 1.1 TOG. It sits at the upper end of what still works over underfloor heating, so it pairs safely only with lower-TOG carpets.

Against the UHMA combined-TOG rule, in-situ resistance is the carpet TOG plus the underlay TOG minus 1. With this underlay at 1.1 TOG, a carpet up to 2.4 TOG keeps the pair under the 2.5 TOG limit.

TOG measures thermal resistance, so a low number means heat passes through easily. For a floor covering over underfloor heating that is what you want. A comfort underlay chosen for warmth underfoot does the opposite job and is the usual reason a heated floor underperforms after a carpet goes down.

Pairings and alternatives

Cormar Pimlico with Duralay Durafit 650combined 1.1 TOG Cormar Primo Textures Ribbed with Duralay Durafit 650combined 1.1 TOG Cormar Primo Textures Weave with Duralay Durafit 650combined 1 TOG Cormar Apollo Plus with Duralay Durafit 650combined 1.2 TOG Cormar Apollo Elite with Duralay Durafit 650combined 1.6 TOG Cormar Fairisle with Duralay Durafit 650combined 1.6 TOG

Sources: Interfloor / Duralay Durafit 650 underlay datasheet · UHMA guidance on underfloor heating with carpet and underlay (combined-TOG rule)