Willoughby City · postcode 2063
Knockdown Rebuilds in Northbridge: What to Keep on the Site
The house goes. The pool, the sandstone and the old fig don't have to.
Northbridge blocks come with things you can't easily buy again: a pool cut into rock decades ago, hand-laid sandstone walls, mature trees, a driveway that finally handles the slope. A knockdown rebuild is a chance to keep the best of the site, if the demolition is planned around it.
Short answer
Can I keep my pool and garden during a knockdown rebuild in Northbridge?
Often, yes. An existing pool can stay if it's structurally sound, protected during demolition and kept behind a compliant temporary barrier the whole time. Sandstone retaining walls and significant trees can be retained with engineering and tree protection zones marked before machines arrive. Plan it into the DA with Willoughby Council, usually 12 to 16 weeks. New homes here cost about $2,860 to $3,450 per m² mid-spec.
Written and reviewed by Oliver Alameri
Licensed builder, NSW Contractor Licence 487805C · Founder, Buildana
Fact-checked
Keeping the pool
Pools in Northbridge are often cut into sandstone and cost a fortune to replace. If the shell is sound, keeping it is usually worth it. A pool builder checks the shell, coping, plumbing and equipment first, because a rebuild is also the time to replace an ageing filter or relocate the pump away from bedrooms.
During the build, the pool stays covered and behind a compliant temporary barrier from the day the permanent fence comes down to the day a new one is certified. Excavators work around it, not over it, and the new house's footings are designed so they don't undermine the pool wall.
- Shell, coping and plumbing inspected before design
- Temporary pool barrier in place for the entire build
- Footings and excavation kept clear of the pool wall
- New fence and barrier certification before handover
A pool cut into rock thirty years ago is worth protecting like a neighbour's house.
Sandstone walls and the old trees
Hand-laid sandstone retaining walls give Northbridge gardens their character, and many hold up the slope the house sits on. An engineer assesses which can stay as they are, which need new drainage behind them and which carry loads the new house will change.
Significant trees sit under Willoughby's canopy controls. Keeping one means fencing off its tree protection zone before demolition starts, bridging or hand-digging near roots, and designing footings to suit. Removing one needs council approval and usually replacement planting.
Want to keep the best parts of your block?
Walk your Northbridge site with me. I'll tell you what's worth keeping, what it takes to protect it through demolition, and what the new home would cost.
0476 300 300Demolition that works around things
A clear-everything demolition is quick. A selective one is slower and costs a little more, because machines have to reach the house without crossing the pool surrounds, root zones or retained walls, and sometimes the last corner of the house comes down with a small machine or by hand while someone watches the pool edge the whole time.
Access matters on a slope. The driveway may be the only way in for trucks. Keeping it? Then it gets protected, or resurfaced at the end. Asbestos in older houses is tested and removed under licence before anything else.
Approval and cost
Everything you plan to keep goes on the DA drawings: the pool, retained walls, trees with their protection zones. Willoughby City Council usually assesses a new dwelling in 12 to 16 weeks.
Adjusted for Northbridge, Rawlinsons' Sydney figures give about $2,860 to $3,450 a square metre for a new home at mid-spec. Keeping a pool or walls usually saves more than the extra care costs. Each is priced after inspection.
Before demolition day
What I'd walk the site for on any Northbridge rebuild.
- 01
Is the pool shell sound, and where is the equipment?
- 02
Which sandstone walls hold up the slope?
- 03
Which trees are significant under council's controls?
- 04
Where can machines get in without crossing retained items?
- 05
Is the driveway being kept or replaced at the end?
- 06
Has the house been tested for asbestos?
Knockdown rebuilds in Northbridge
Can I keep my swimming pool during a knockdown rebuild?
Usually, if the shell is sound. It must stay behind a compliant temporary barrier throughout construction and be protected from machinery.
Can old sandstone retaining walls be kept?
Many can, after an engineer checks their condition, drainage and how the new house's loads affect them.
Will council let me take out a tree for the rebuild?
For significant trees, yes. Willoughby's canopy controls usually require approval and replacement planting.
Is selective demolition more expensive?
Slightly, because it takes more care and time. Keeping a pool or walls usually saves far more than the extra demolition cost.
Sources and references
Costs are from the Rawlinsons handbook with the local cost index applied; rules and timeframes are checked against the sources below.
A new house on a garden that's already grown.
A Northbridge knockdown rebuild that keeps what took decades to create.