Inverted Warm Roof Construction

Simply defined as a type of roof construction where the waterproofing layer lies beneath the insulation instead of above it as in other forms of roofing inverted roofs ensure that the complete roof construction including roof covering is kept at warm temperatures during winter months and at moderate temperates during the summer months.

Inverted warm roof construction.

No vapour control layer is required. This makes it the only material suitable and approved for inverted roof applications. An inverted roof is quite simply where the waterproofing layer is installed over the structural deck rather than over the insulation. In an inverted roof construction the principal thermal insulation layer is located not only above the roof structure but also above the waterproofing resulting in the waterproofing structural deck and support structure being at a temperature close to that of the interior of the building.

This means that the insulation should be highly resistant to water absorption for example an extruded polystyrene based product which will not be affected by water or repeated freeze thaw cycles. An inverted roof construction sees the principal thermal insulation layer located above the roof structure and also above the waterproofing this method results in the waterproofing the structural deck and the support structure all being at a temperature similar to that of the interior of the building. An inverted roof also referred to as a protected membrane or upside down roof is form of flat roof in which the waterproofing layer is beneath the thermal insulation rather than above it. Insulation boards are loose laid on top of the membrane and then weighted down with paving slabs or gravel ballast.

Inverted roofs are designed with the waterproofing layer usually a liquid applied membrane beneath the insulation.