Underlay TOG rating

Cormar Trinity TOG value and underfloor heating

The published Cormar TOG value for Cormar Trinity and the underlay budget it leaves over a heated floor.

1.6TOG

Suitable for UFH

Leaves 0.9 TOG of the combined budget for the carpet on top before the 2.5 TOG limit is reached.

PassMarginalFail

Published value

Range	Cormar Trinity
Construction	wool-blend saxony
TOG rating	1.6 TOG
Max underlay TOG for UFH	1.9 TOG

Cormar Trinity is a wool-blend saxony with a published TOG value of 1.6. A wool-blend saxony rated 1.6 TOG, needing a low-TOG underlay to clear the combined limit.

Using the UHMA rule, in-situ resistance is carpet plus underlay minus 1. To keep Cormar Trinity under the 2.5 TOG limit the underlay must be no more than 1.9 TOG.

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.

Underlay pairings

Cormar Trinity with Duralay Technics 5combined 1.16 TOG Cormar Trinity with Duralay Heatflow for Carpetcombined 1.35 TOG Cormar Trinity with Tredaire King (Duralay King)combined 1.4 TOG Cormar Trinity with Duralay Durafit 650combined 1.7 TOG Cormar Trinity with Tredaire Softwalkcombined 3.29 TOG Cormar Trinity with Tredaire Dreamwalkcombined 3.73 TOG

Sources: Cormar Carpets published carpet TOG values · UHMA guidance on underfloor heating with carpet and underlay (combined-TOG rule)