Innovation built on experience

ProctorGeo IRMA


ProctorGeo IRMA is designed for use as a separating layer in ballasted or paved Inverted Roof Membrane Assembly (IRMA) flat roofs.

ProctorGeo IRMA acts as a filter layer preventing fines and other debris from passing through, and also as a water flow reducing layer minimising cold rainwater flowing between the insulation and the roof waterproofing thus reducing the consequent rainwater cooling effect.

Rainwater that penetrates IRMA roof systems reaching the waterproof layer can impact on the thermal performance of the construction. To take account of this loss in thermal performance, the initial R-value of the roof should be corrected by subtracting a rainwater correction factor (determined using the method described in BS EN ISO 6946:2007) dependent on local rainfall and the proportion of rainwater reaching the waterproof layer under the insulation.