In a pitched roof with insulation above a bituminous membrane, the waterproofing layer is installed over the supporting structure and the thermal insulation is positioned above it, beneath the layers supporting the final roof covering.
This configuration requires an insulation material suitable for its position above the waterproofing layer and capable of maintaining its thermal and mechanical performance under the expected roof service conditions.
Extruded polystyrene (XPS) is particularly suitable for this application due to its low water absorption, mechanical strength and dimensional stability.
X-FOAM® HBD is an XPS thermal insulation board with an extrusion skin and four straight edges. With a compressive strength of ≥ 300 kPa, it provides a robust thermal insulation layer for pitched-roof applications above compatible waterproofing systems.
The roof build-up can also incorporate micro-ventilation beneath the tiles, creating an air space between the insulation system and the external roof covering.