To insulate the ground floor we have used 150mm thick Polyisocyanurate insulation, this reduces heat loss through the floor by almost double the mandatory target. Polyisocyanurate or (PIR) insulation has an almost unmatched level of thermal resistance and today is commonly specified in a wide variety of applications. Although ‘man made’, much of the raw component is recycled content, PIR board has zero ozone depletion potential and virtualy no global warming potential.
Highlighted in the detail above and shown in the photograph is a load bearing insulating element which is laid at low level as part of the cavity wall inner skin, this is used to prevent ‘cold bridging’, essentialy this greatly reduces potential heat loss through the internal blockwork to maintain a very low overall ‘U’ value. The ‘U’ value is the rate of thermal transmittance and when calculated takes into account the gauge or thickness of the material. The load bearing insulating element we have used is similar to PIR board but with a much higher compressive strength.