A treadable inverted roof is a flat-roof construction in which the thermal insulation is installed above the waterproofing membrane and the upper surface is designed to accommodate pedestrian use.
As in other inverted roof systems, positioning the insulation above the waterproofing layer helps protect the membrane within the roof build-up. The insulation is subsequently covered by the layers required to create the finished, walkable surface, which may include cement or ceramic paving depending on the selected roof system.
Extruded polystyrene (XPS) is particularly suitable for this application because it combines low water absorption with high compressive strength and is suitable for the conditions encountered above the waterproofing layer.
X-FOAM® HBT can be used as the thermal insulation layer in treadable inverted roofs. Its shiplap edges allow adjacent boards to be accurately coupled, while its compressive strength of ≥ 300 kPa makes it suitable for roof build-ups where the insulation is subjected to the loads transferred by the overlying layers and pedestrian use.
As with other inverted roof systems, the effect of rainwater flowing between and beneath the insulation boards must be considered when determining the thermal performance of the complete roof build-up.
