The Canberra knock-down rebuild checklist: approvals, asbestos, trees and footings

What approvals does a knock-down rebuild need in Canberra?

A knock-down rebuild in Canberra needs approval for two things: taking the old house down and putting the new one up. Between them sit checks for asbestos, trees, utilities, bushfire and heritage, usually in this order.

Your certifier and designer confirm which checks apply to your block.

Can you knock down a house in Canberra without a DA?

Yes, if it's a single dwelling with no shared party wall and the neighbours get written information before demolition starts. Miss either condition and the demolition needs development approval.

The party wall rule catches Canberra's red-brick duplexes, built from the 1920s and again after the war: two homes sharing one wall. Taking down one half is not exempt, and the half that stays is at risk. In a 2013 Yarralumla case reported in the Canberra Times, an attached half was left with "gaping holes in her walls" after the other half came down.

No ACT law requires a dilapidation report before demolition or excavation. Master Builders ACT says one "should be treated as essential", which is advice rather than law. A dilapidation report is a dated, photographed record of the neighbouring building's condition before work starts, from $750 + GST ($825 inc GST).

What asbestos checks come before demolition?

Two. If the house was built or started before 1985, the Building Act requires an asbestos removal control plan with any building approval application for it. And before anyone starts, check whether the house is on the loose-fill asbestos (Mr Fluffy) Register.

The Register listed 17 remaining affected homes at 8 October 2026. A home on it allows only work essential for health, safety or reasonable living conditions, or demolition. Most affected houses have already gone: the ACT Government says the vast majority have been demolished, and the remediated blocks resold and rebuilt. So a former Mr Fluffy block can be a normal rebuild site.

We check the Register before any visit. We never enter or inspect affected roof spaces or subfloors, and we don't test for asbestos. See our guide to older homes and asbestos in the ACT.

What if there's a protected tree on or next to the block?

Then the tree shapes the job. Under the Urban Forest Act 2023, a tree on private land is protected if it is 8 m or taller, has a canopy 8 m or wider, or has a trunk circumference of 1 m or more at 1.4 m above the ground. Every tree on public land is protected, including verge trees.

Inside the tree's protection zone (the canopy area, plus 2 m beyond it, plus 4 m around the trunk), digging deeper than 100 mm over 4 m² or more is prohibited groundwork. So is compacting more than 10% of the zone, which demolition machinery and stored materials can do.

Tree management plans are now compulsory in DA and BA applications where a protected tree may be affected, including one on the neighbour's side. We design footings that keep digging out of the zone, such as piers and beams in place of a slab edge. Our guide to protected trees and building in the ACT explains the rules.

What else can hold up a rebuild?

Sewer mains, bushfire mapping and, on some blocks, the National Capital Authority. Check each one early.

• Icon Water. Its guidance says its building approval is needed before work starts, even where no planning approval is required, and footings are not permitted inside a pipe's protection envelope. We don't quote clearance distances from memory. See building near a sewer in Canberra.
• Bushfire. If the block is on the ESA bushfire map, the DA may carry a BAL condition or need a site-specific BAL assessment by a bushfire consultant. DA-exempt homes take their BAL rules from the district development controls. We don't do BAL assessments; we design to the BAL that's set.
• The National Capital Authority. In Designated Areas, such as parts of Deakin and Forrest and blocks on main avenues, the NCA approves works instead of a DA. A building approval is still needed.

What rules apply to the new house?

The new house is DA-exempt only if it meets the single dwelling development controls and the neighbours are informed. It then needs building approval like any new home, because there are no BA exemptions for detached houses.

Sources: Territory Plan E01 rule 10; ACT NCC page; NI2025-492 control 17; Building (General) Regulation ss 33–34; Building Act s 69.

What engineering does the new house need?

The certifier needs structural details to lodge the BA: footing and slab details with the "nominated founding depth and description of founding material", reinforcement and concrete strength, retaining wall details, and framing, bracing and tie-downs. That list comes from form AF2025-18, the ACT's minimum documents for house BAs.

The new house won't sit on the ground the old one was built on. Demolition leaves old footings and disturbed soil, and any cut or fill changes it again. Published new-estate site reports say the class must be reassessed after cut or fill; the same logic applies here.

Canberra's ground varies, too. The rock is often deeply and unevenly weathered, so it can be near the surface on one part of a block and metres down on another. The soil mapping for the landscape most suburbs sit on notes "a considerable range in profile form occurs within a small area". No ACT law names a geotechnical report, so we write footing design for your site's soil, and we arrange a soil test at cost when the design needs one.

How much does a knock-down rebuild cost in Canberra?

We can't give you a build cost: there's no official Canberra data on rebuild costs or numbers, and builders price the build. Here is what the engineering costs.

Starting prices for a typical house. Your fixed quote confirms the price before we start, and says if a site visit is needed.

News reports say owners commonly knock down 1960s ex-govvies. If you're weighing up renovating against rebuilding one, our guide to renovating an ex-govvie covers the other path.

When should you call a structural engineer?

Call once you have a house design, or earlier if the block has a protected tree, a sewer main, a slope or an attached neighbour. Each one changes the footing design.

• Design for the new house: knock-down rebuild engineering, a fixed quote from your plans.
• Footings and site class only: footings, slabs and site classification from $1,290 + GST ($1,419 inc GST).
• An attached or close neighbour: a dilapidation report before demolition.

Weston Creek, for example, has many rebuilt homes beside its 1970s houses, some replacing homes lost in the 2003 fires and some on remediated Mr Fluffy blocks. See structural engineering in Weston Creek.

We're engineers only. We don't demolish, build or recommend builders, so the design isn't written around anyone's contract. Send your plans, add up to 5 files, and we reply with a fixed quote in under 20 minutes on average, during business hours.