Question4
4. What is the U-Value required from the 1/4/02 to
meet the requirements of Part L when insulation is fitted between
the rafters?
The U Value required would be 0.20W/m2K. One way to achieve
this with 48mm x 150mm deep rafters at 600mm centres would be to
install 140mm of Crown FrameTherm 35 between the rafters. The
rafters are then underlined with our Polyfoam Linerboard (36/9.5)
which is 36mm of extruded Polystyrene laminated to 9.5mm
Plasterboard.