Inverted Membrane Roof

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.

Inverted membrane roof.

Invented by dow in the late 1960 s an inverted roof system uses dupont styrofoam brand xps insulation to protect the membrane helping improve the performance and longevity of the entire roof system. Also known as a protected membrane or upside down roof inverted roofs employ insulation which can resist water absorption provide excellent thermal performance be unaffected by freeze and thaw cycles withstand surface traffic and be protected from uv and mechanical damage among others. These systems are typically applied in conditions where there is extensive roof traffic or to protect from excessive weather conditions such as multiple hail events. It is therefore essential the insulation layer is rot proof and durable.

Inverted roof membrane assembly irma offer superior protection of the roof membrane from foot traffic and mechanical damage. In an inverted membrane system the coventional membrane arrangement is invereted or turned upside down. This makes it the only material suitable and approved for inverted roof applications. Inverted roof systems are also referred to as upside down roof assembly.

An inverted roof is quite simply where the waterproofing layer is installed over the structural deck rather than over the insulation. Rigid extruded polystyrene insulation has minimal water absorption due to its closed cell structure. Good insulation qualities and low thermal conductivity are required to ensure the low u value of the roof. An inverted roof also known sometimes as a protected membrane or pmr roof uses the same materials as a conventional roof but places insulation on the top of the membrane.

Benefits of inverted roofs. Whilst the inverted roof is a robust system the insulation layer does not benefit from the protection of the waterproofing membrane. Inverted roofs are designed with the waterproofing layer usually a liquid applied membrane beneath the insulation. In an irma the system s insulation is installed above the waterproofing membrane instead of below as in a conventional roof assembly.

Inverted roof membrance assembly irma systems are used in applications where the membrane requires protection from site specific hazards. Insulation boards are loose laid on top of the membrane and then weighted down with paving slabs or gravel ballast.