Another increasingly important area. With changes in Building Regulations and the UK Govt’s policy on carbon emission reduction generally, the thermal insulation requirements of many doors and also windows are increasing.

A thermal insulation value is expressed as a “u-value” (W/m²k), where a lower number indicates a higher level of insulation. Building Regulation Document L dictates that many doors have to have a “u-value” of no higher than 1.4 W/m²k.