Extending an existing fence typically costs $50 to $110 per metre inc GST, depending on how much height you add and whether the existing posts can carry it. It is almost always cheaper than replacing the fence, provided the posts and footings are sound.
Typical cost: $50 to $110 per metre inc GST
Colorbond extension, 300mm: $50 to $70 /m. Post extenders and matching sheet
Colorbond extension, 600mm: $70 to $95 /m. Bracing usually required
Timber lattice topper, 300mm: $55 to $80 /m. Treated pine lattice and framing
Timber lattice topper, 600mm: $80 to $110 /m. Heavier framing, more fixings
New post extenders: $45 to $75 each. Bolted to existing posts
Post replacement where needed: from $140 each. If the existing post is failing
When an extension makes sense
Extensions are ideal when the fence itself is fine but the height is not. Common triggers are a new two storey build next door, a pool or spa going in, a dog that has learned to jump, or simply wanting more privacy in a backyard that has become overlooked.
The economics are simple. A new 1.8 metre Colorbond fence starts around $130 per metre. Adding 600mm of height to what you already have starts around $70 per metre. If the posts are sound you save roughly half.
The test is the posts. Push hard on a few along the run. If they move at the base, the footing has failed and no extension will fix that. In that case the honest answer is a rebuild, and we will tell you at the site check rather than bolt height onto a fence that will lean within a year.
Height rules in Victoria
Most Victorian councils allow a boundary fence up to 2.0 metres between neighbours without a planning permit, and lower limits often apply on a street frontage. Overlays, heritage controls and corner blocks can change that.
Under the Fences Act, if you want your neighbour to contribute you need to serve a fencing notice and agree on the work. If you are extending purely for your own benefit, expect to fund it yourself.
We do not lodge permits for you, but we will tell you when a job looks like it needs one so you can check with your council before booking.
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