Brockway Discovery (1.9 TOG) with Duralay System Ten (1.55 TOG) gives a combined 2.45 in-situ TOG. Whether that passes the 2.5 TOG underfloor heating limit and what to do.
Updated 05 September 2026.
Brockway Discovery and Duralay System Ten: combined TOG for underfloor heating
The combined TOG for Brockway Discovery over Duralay System Ten, worked against the UHMA underfloor heating rule.
Combined against the UHMA 2.5 TOG underfloor-heating limit. Under 1.5 also suits a low-temperature heat pump.
| Carpet | Brockway Discovery (1.9 TOG) |
|---|---|
| Underlay | Duralay System Ten (1.55 TOG) |
| Published sum | 3.45 TOG |
| UHMA in-situ correction | minus 1 TOG |
| Combined in-situ TOG | 2.45 TOG |
| Standard UFH limit | 2.5 TOG |
| Heat pump target | under 1.5 TOG |
Brockway Discovery is rated 1.9 TOG and Duralay System Ten is rated 1.55 TOG. Laid together the combination is what the underfloor heating has to warm through.
The published TOG figures add to 3.45. The UHMA rule subtracts 1 TOG because tests showed real in-situ resistance runs about a TOG below the paper sum, giving 2.45 TOG. On a heat pump running low flow temperatures the floor has less heat to push, so aim under 1.5 TOG and prefer the thinnest underlay in this range.
Questions and answers
Brockway Discovery and Duralay System Ten: combined TOG for underfloor heating?
Combined in-situ TOG is 2.45, under the 2.5 TOG limit, so Brockway Discovery with Duralay System Ten is suitable for a standard underfloor heating system. It is above 1.5 TOG, so on a low-temperature heat pump run choose a thinner underlay.