18/09/2026
Roof Penetrations - Managing Water Ingress Around Rooftop AC
Water ingress around rooftop air conditioning equipment can become an ongoing concern for commercial tenancies, particularly when several roof penetrations are concentrated within the same area.
At this tenancy, the AC unit had already been replaced, however the surrounding roof area still required attention. The existing AC chute had developed rust, steel supports were penetrating through the roof sheets, and water was collecting around sections of the roof penetrations.
When water continues to sit around these areas, it can increase the likelihood of moisture finding its way into the building. For an operating retail tenancy, this can potentially lead to internal water damage, additional maintenance requirements and disruption if the underlying roof details aren’t addressed.
Previous sealing works had been carried out around sections of the roof, but the area required additional flashing and waterproofing to better manage how water moved around the penetrations.
For this completed project, Build Technics carried out roof rectification and waterproofing works around the affected AC areas, including the installation of new back tray flashings to help capture and direct water away from the penetrations.
The works helped address:
✅ Water collecting around AC roof penetrations
✅ Areas around steel supports penetrating the roof sheets
✅ Existing roof areas requiring additional waterproofing
✅ Water ingress risk to the tenancy below
✅ Protection around the rusted AC chute ahead of its future replacement
For commercial and retail properties, roof leaks aren’t only a building maintenance concern. When left unresolved, they can potentially affect internal finishes, stock, fixtures and day-to-day operations within the tenancy.
This project highlights the importance of looking beyond where water is appearing internally and identifying the roof conditions that may be contributing to the issue.
Addressing those areas early can help protect the tenancy below and reduce the likelihood of a roof issue becoming a larger operational and maintenance concern.