K7 Sarking Board is designed for use in pitched roof applications and allows an increased level of usable space compared with insulation applied at ceiling level. It eliminates the risk of condensation within the roof space and avoids all problems attendant with it. It is possible to use K7 either on top of the rafters when the roof timbers are exposed, or between the rafters when applying the boards from beneath (often in a retrofit attic conversion). In the latter case, it is necessary to retain a ventilated airspace of 50mm above the insulation. K7 is the only product currently available, that can retain this airspace and achieve the 0.25 U value required, using standard rafters with depths of 113mm.