Underlay TOG rating

Duralay System Ten TOG rating and underfloor heating

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

1.55TOG

Too warm for UFH

Leaves 0.95 TOG of the combined budget for the carpet on top before the 2.5 TOG limit is reached.

PassMarginalFail

Duralay System Ten is rated 1.55 TOG. That alone is above the 2.5 TOG combined limit for underfloor heating, so it is not suitable over a heated floor with any carpet.

Published datasheet

Manufacturer	Interfloor (Duralay)
TOG rating	1.55 TOG
Thickness	9.2 mm
Density	crumb rubber
Sound	32 dB impact reduction
Underfloor heating	Not suitable

System Ten is a heavy 9.2 mm crumb-rubber contract underlay rated 1.55 TOG. Its comfort and durability come from thickness that also traps heat, so above the 1.3 TOG underlay ceiling it is a poor match for underfloor heating.

Because Duralay System Ten is already 1.55 TOG before any carpet is added, no carpet brings the pair back under the 2.5 TOG limit. Over underfloor heating, swap it for a low-TOG underlay instead.

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 System Tencombined 1.55 TOG Cormar Primo Textures Ribbed with Duralay System Tencombined 1.55 TOG Cormar Primo Textures Weave with Duralay System Tencombined 1.45 TOG Cormar Apollo Plus with Duralay System Tencombined 1.65 TOG Cormar Apollo Elite with Duralay System Tencombined 2.05 TOG Cormar Fairisle with Duralay System Tencombined 2.05 TOG

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