Tredaire King (Duralay King) TOG rating and underfloor heating
The published TOG and datasheet figures for Tredaire King (Duralay King), and what it means over a heated floor.
Leaves 1.7 TOG of the combined budget for the carpet on top before the 2.5 TOG limit is reached.
| Manufacturer | Interfloor (Duralay / Tredaire) |
|---|---|
| TOG rating | 0.8 TOG |
| Thickness | 8.3 mm |
| Density | 510 kg/m3 |
| Sound | 42 dB impact reduction |
| Underfloor heating | Suitable |
King pairs a low 0.80 TOG with a high 510 kg/m3 density, so it lets heat through quickly while still supporting the carpet underfoot. It is the go-to underfloor-heating underlay where a thicker, more comfortable feel is wanted than Heatflow gives.
Against the UHMA combined-TOG rule, in-situ resistance is the carpet TOG plus the underlay TOG minus 1. With this underlay at 0.8 TOG, a carpet up to 2.7 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.
Sources: Interfloor / Duralay Tredaire King underlay datasheet · UHMA guidance on underfloor heating with carpet and underlay (combined-TOG rule)