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.
Inverted deck roof.
For a case study of an inverted roof defect see inverted roof defect case study.
For more information see specifying insulation for inverted roofs.
Inverted roofs typically last longer than traditional ones.
Inverted n dek is the 3 inch n dek profile placed in the inverted position for a unique ceiling aesthetic that provides a smooth ceiling appearance with heavy shadow lines.
However once the roof deck and the membrane warms up the condensation will be able to evaporate.
Rigid extruded polystyrene insulation has minimal water absorption due to its closed cell structure.
This makes it the only material suitable and approved for inverted roof applications.
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.
Problems can occur if the accumulation of condensation persists.