A balustrade bolted through a balcony hob in Clyde North
Fixing a balustrade down through the top of a balcony hob puts holes in the waterproofing. What we found at a Clyde North handover.
In short: Upstairs balconies are a waterproofing problem before they are a safety one. At a Clyde North pre-handover in September 2026 the balustrade was fixed straight down through the waterproofed hob.
The detail
A balcony hob is the upstand at the edge of a balcony. The membrane runs over or behind it to keep water out of the structure below. Bolting a balustrade down through its top surface creates a hole through that membrane at every fixing.
What we saw
The fixings were clearly visible from above, driven through the horizontal face of the hob. We could not confirm what waterproofing sat underneath, so the report recommended the builder confirm the detail and how each penetration was sealed.
Why it matters
Water entering at a balustrade fixing travels into the frame or slab edge below, often over a garage or living room. It can take years to show, and by then the timber and plaster below are damaged and the source is hard to prove.
Related items the same month
Other Clyde North handovers that season recorded a bath hob broken open to repair a waste pipe, and door thresholds where the water stop stopped short of the wall flashing. All three are edges of a waterproofing system, which is where systems fail.
What to ask your builder
Ask for the balustrade manufacturer's fixing detail and the waterproofer's detail for the balcony, and for written confirmation that the fixings were sealed in accordance with both.
Written by our local inspection team from work carried out in Clyde North. Licensed building practitioners, Building & Plumbing Commission registration CDB-U 53425.
