Other Insulation

Reflective foils are not defined as insulating, because they are only somewhat effective against radiative heat loss and have little impact on conductive and convective mechanisms. They also increase the potential for electrocution. As they are non-absorbent, they are not permitted as residential roofing underlay in New Zealand.

When Polyester blanket insulation is used in conjunction with metal roof cladding, special roofing screws should be used to avoid binding.

Composite insulated metal panels are described in Insulated Panels.

Insulation must not be laid over the purlins as this compromises the air gap and the efficiency of the insulation where the roofing compresses it.