In contrast to thermal insulation between rafters, pitched roofs feature an over-rafter insulation system. Insulation boards are laid on a formwork over the rafters. This has the advantage that very large thicknesses of insulation can be achieved in this way (over-rafter insulation plus full-fill rafter insulation), while creating space underneath. XPS is ideal for pitched roof insulation applications as a result of its:
- Excellent water and water vapour resistance.
- Superior dimensional stability.
- Exceptional load capacity.