Inverted Deck Roof

Problems can occur if the accumulation of condensation persists.

Inverted deck roof.

For a case study of an inverted roof defect see inverted roof defect case study. Rigid extruded polystyrene insulation has minimal water absorption due to its closed cell structure. Inverted n dek acoustical is a 3 inch deep wide rib inverted acoustical structural roof deck unit that provides a support surface for various types of roofing materials. Inverted roofs have significantly lower maintenance costs than conventional low slope roofs thanks in large part to the insulation in the inverted assembly protecting the roof membrane from mechanical damage during and after construction as well as temperature extremes that cause stress.

Inverted roofs typically last longer than traditional ones. When the insulation was removed from the worst affected area a large number of water filled blisters were found in the waterproof membrane figure 1. For more information see specifying insulation for inverted roofs. Bre investigated a large building with an inverted roof that was suffering from persistent leaks with water dripping from the underside of the roof and on to suspended ceiling tiles.

An inverted roof is quite simply where the waterproofing layer is installed over the structural deck rather than over the insulation.