Mounting Air Conditioning, Aerials, and Solar Units

Structures mounted on the roof requires consideration of all the factors contributing to the performance of the roof cladding.

Some structures which are commonly mounted on roofs include air conditioning units, aerials, photovoltaic systems, and solar water heating units.

Design and installation of these structures should consider at least three areas of performance:

1. Structure – the effect of mounting the structures and roof traffic for ongoing maintenance; see Dead Loads and Roof Traffic.
2. Durability – corrosion may result from issues such as wet contact, capillary action, unwashed areas, material compatibility, and runoff; see  Other Causes of Corrosion.
3. External Moisture – penetrations influence roof drainage and can affect weatherproofing of the cladding; see Penetration Durability.