IRMA Roof Design Guide

At DCTech we believe the best way to ensure a troublefree roof is to build it upside-down using an Inverted Roof Membrane Assembly [IRMA] system in which the thermal insulation is located above the waterproof layer.

The IRMA flat roof approach has been successfully adopted since the 1970s across Europe & North America and was  applied on New Parliament House in Canberra.

The IRMA roof offers numerous advantages. When specified with a suitable compressive strength of extruded polystyrene (XPS) thermal insulation, an appropriate surface protection (such as ballast, pavers, screed or a green roof) and the right warterproofing and water shedding layers, an IRMA roof provides:

Protection The waterproofing membrane is protected from UV and thermal stress by the DCT XPS insulation and the surface protection layer.

Ease of maintenance Ballast or pavers and ProctorGeo IRMA water shedding layers can easily be peeled back to inspect the insulation or waterproofing layer.

Condensation mitigation By ensuring that the concrete is kept close to warm indoor temperature by the external insulation, condensation risk is mitigated.