Inverted Ballasted Roof

Drawbacks of a ballasted roof system.

Inverted ballasted roof.

Ballast stone traps a lot of dirt making patching difficult. Roofs with pavers as ballast can be used as outdoor patios. 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. The total system usually weighs between 100 to 145 kg m2.

Insulation boards are loose laid on top of the membrane and then weighted down with paving slabs or gravel ballast. When the concept first came to the u s plenty of roofers scratched their heads and wondered how the roof stayed on without being anchored especially during high winds or storms. Extremely difficult to find a leak in this system since the membrane is well hidden. The iko permatec inverted ballasted roof provides a protected membrane system which usually incorporates insulation.

It is however ballasted generally with gravel. The firestone epdm ballasted system is an economical epdm roofing system suitable for a wide variety of buildings it can be applied on any building that can accommodate the extra load of the ballast and where the roof slope does not exceed 10. 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. Firestone epdm ballasted system application.

Inverted roofs are designed with the waterproofing layer usually a liquid applied membrane beneath the insulation. A ballasted roof means that the roof membrane is not anchored or adhered in any way to the decking material.