TogCheck
Underlay TOG rating

Cormar Fairisle TOG value and underfloor heating

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

1.52.5
1.5TOG
Suitable for UFH

Leaves 1 TOG of the combined budget for the carpet on top before the 2.5 TOG limit is reached.

PassMarginalFail
Published value
RangeCormar Fairisle
Constructionwool-blend berber
TOG rating1.5 TOG
Max underlay TOG for UFH2 TOG

Cormar Fairisle is a wool-blend berber with a published TOG value of 1.5. A wool-blend berber rated 1.5 TOG. It works over underfloor heating only with one of the lower-TOG underlays.

Using the UHMA rule, in-situ resistance is carpet plus underlay minus 1. To keep Cormar Fairisle under the 2.5 TOG limit the underlay must be no more than 2 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 Fairisle with Duralay Technics 5combined 1.06 TOGCormar Fairisle with Duralay Heatflow for Carpetcombined 1.25 TOGCormar Fairisle with Tredaire King (Duralay King)combined 1.3 TOGCormar Fairisle with Duralay Durafit 650combined 1.6 TOGCormar Fairisle with Tredaire Softwalkcombined 3.19 TOGCormar Fairisle with Tredaire Dreamwalkcombined 3.63 TOG

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