Roof Leaks on Commercial Buildings – Part 2

Roof leaks on commercial buildings can often be sourced to poorly installed air conditioning units. In Part 1 of this series we demonstrated how roof leaks on commercial buildings can be caused by too many ac unit pipes running through one penetration. In addition, we showed how roof leaks can also be caused by the ac unit being positioned on treated pine timber struts.

Air Conditioning Flashing

In Part 2 of our series, our video shows poorly installed air conditioning unit flashings. The result is, of course, a leaking roof.

Roof flashings are a vital element of the roofing system as they are used to transition from the roofing material to something that is not a roof. Typically on a metal roof the flashing is also metal.

In the case of an air conditioning unit, metal flashings are required to create a watertight join between the unit and the roof sheets. The metal flashings need to be riveted and sealed into place to prevent water entering between the joins. Ideally, the silicone sealant should be applied to the underside of the flashing join to limit the breakdown of the sealant which naturally occurs over time with exposure to weather.

See our pics of flashings we’ve installed to rectify leaking ac units. Flashings are a permanent solution for this type of problem. The application of a liquid rubber membrane is an alternative cheaper but short term solution for this type of problem. We’ve included some pics of this fix too.