Small Mechanical Units

Small mechanical units are often being installed on existing roofs and even on new roofs with no attachment to the building. In high winds, these units may blow over. A unit secured to sleepers - see Image 2 - may rock on the sleepers and eventually wear holes in the roof membrane. Adding patio pavers - see Image 3 - with a foam cushion below the pavers is an improvement. However, the better solution is achieved by bolting the sleepers to the pavers to give a larger and heavier base for the unit - see Image 4. 

Some of these units are now so tall that the only secure solution is achieved by bolting the unit to sleepers which have been secured to the roof structure - see Image 5.