In short: A Tallawong investigation found a balcony with no overflow, an undersized drain and cracked screed, plus a box gutter with no sump. Each is cheap at design stage and expensive after tiling.
Why balconies are everywhere here
Tallawong lots are narrow, so houses go up. A second storey often comes with a balcony over the garage or living room, and with a box gutter or two hidden behind a parapet.
What one house showed
In November 2025 we investigated a Tallawong home where water was the complaint. The balcony had no overflow, its drain pipe was smaller than AS/NZS 3500.3 calls for and the screed under the tiles was cracking. Up on the roof, a box gutter had been built without a sump.
How to check your own
Look for a second outlet or spitter through the balcony edge above the main drain. Check that water runs to the drain rather than the door. On the roof side, any box gutter should discharge through a sump and rainhead, not straight into a downpipe.
When to catch it
The waterproofing stage, before tiles go down, is the cheapest point to fix an outlet. At handover it is still the builder's job. After that, it becomes a warranty claim.
Written by our local inspection team from work carried out in Tallawong. Licensed building practitioners, NSW Fair Trading licence 366177C.
