Foil-Tec - Suspended Timber
The heat loss in a floor is greater at the exposed perimeter edge of the floor. To calculate the U-Value, the exposed perimeter edge to area ratio needs to be worked out e.g. – a 100m² area, semi-detached house with 3 external walls of 10m each has a perimeter edge to area ratio of 0.3 (i.e. 30m ÷ 100m² = 0.3) Overall thermal transmittance (U-value) of suspended floors should be calculated using BS EN ISO 13370.
In many cases Foiltec Double used in suspended timber floors will meet Building Regulations requirements with no additional measures.
- Foil-Tec is rolled out with the shiny side facing upwards, over the joists
- Foil-Tec is then nailed in place through the Foil-Tec Saddle Clips to maintain required air gap – 4 per m²
- The horizontal joints are overlapped by 100mm and are left open to allow any moisture accumulation to dissipate
- Foil-Tec must be brought up (behind the skirting board) to 75mm
- The decking is then fixed with screws (at 200mm centres) 37mm into the joists
|P/A Ratio||U-Value (with 50mm Cavity)||U-Value (with 100mm Cavity)|
|0.2||0.24 W/m²K||0.22 W/m²K|
|0.4||0.30 W/m²K||0.37 W/m²K|
|0.6||0.33 W/m²K||0.30 W/m²K|
|0.8||0.34 W/m²K||0.31 W/m²K|
|1.0||0.36 W/m²K||0.32 W/m²K|