Box gutters, parapets and the overflow that does not overflow
Non compliant box gutter overflows and flat parapet capping on Fraser Rise roofs.
In short: Modern facades in Fraser Rise hide the roof behind parapets. That makes the box gutter and its overflow the most important drainage on the house.
Why box gutters are risky
They sit inside the roof line. When a box gutter overflows the wrong way, the water goes into the house, not over the edge.
What we found
An overflow built so that roof water could run straight into it, and a design that does not follow the deemed to satisfy methods in AS 3500.3.
Parapet capping
Capping must slope at least 5 degrees so water runs off. We recorded capping laid flat or falling the wrong way.
Flashings beside them
Wall flashings fixed at more than 100 mm centres can lift in wind and let water behind the cladding.
Before you settle
Each of these is a roof plumber's fix with the scaffold gone but the builder still responsible. Afterwards it is your ceiling.
Written by our local inspection team from work carried out in Fraser Rise. Licensed building practitioners, Building & Plumbing Commission registration CDB-U 53425.
