TogCheck
Underlay TOG rating

Cormar Riva TOG value and underfloor heating

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

1.52.5
1.8TOG
Suitable for UFH

Leaves 0.7 TOG of the combined budget for the carpet on top before the 2.5 TOG limit is reached.

PassMarginalFail
Published value
RangeCormar Riva
Constructionwool-blend saxony
TOG rating1.8 TOG
Max underlay TOG for UFH1.7 TOG

Cormar Riva is a wool-blend saxony with a published TOG value of 1.8. A luxurious wool-blend saxony rated 1.8 TOG. Only the lowest-TOG underlays keep it under the combined limit over underfloor heating.

Using the UHMA rule, in-situ resistance is carpet plus underlay minus 1. To keep Cormar Riva under the 2.5 TOG limit the underlay must be no more than 1.7 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

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