Rainheads, cappings and roof water on Werribee handovers
Why overflow slots, top-fixed cappings and missing spreaders keep appearing on handover reports.
In short: Box gutters and parapets look clean on modern facades, but they need careful detailing to keep water out.
Rainhead overflows
Overflow slots in box gutter rainheads are no longer permitted. An open weir or an approved alternative is needed so that, if the downpipe blocks, water spills safely outside rather than back into the roof.
Cappings fixed through the top
Wall and parapet cappings should be fixed from the sides. A screw through the top is a hole facing the sky, and water follows it in.
Water lying on cappings
Where a capping has no fall, water sits on it, staining and eventually corroding it, and leaking at any fixing.
Spreaders and penetrations
An upper gutter discharging onto the roof below needs a spreader, and every roof penetration needs proper flashing. Both are items we have recorded on Werribee handovers.
Written by our local inspection team from work carried out in Werribee. Licensed building practitioners, Building & Plumbing Commission registration CDB-U 53425.
