Guides
Guides: building, buying and renovating in Canberra
Sixteen guides to the questions Canberra homeowners ask most. Each one answers first, then gives the ACT rule, the number and its condition, and the official source.
Approvals and rules
What needs approval in the ACT, and who gives it?
Who does what, what needs development or building approval, and the height and size limits for common jobs around the house.
Ground and cracks
Why do Canberra houses crack and move?
How to read a crack, why the ground under Canberra changes so much from block to block, and what underpinning really costs.
Cracks in walls in Canberra: when to worry
Which cracks are cosmetic, which point to footing movement, and what to record before you call anyone.
SoilsCanberra soils and footings
Weathered rock, mapped soil hazards and AS 2870 site classes: why one block differs from the next.
CostsHow much does underpinning cost in Canberra?
Published Canberra price ranges, what drives them, and when fixing the cause means you don't need underpinning.
TreesProtected trees and building in the ACT
What the Urban Forest Act protects, the digging limits near a protected tree, and what needs approval.
Buying and selling
Buying or selling a Canberra home?
Most ACT home sales come with a seller's building and compliance report. It's worth knowing what it must cover, and what it doesn't.
The seller's building and compliance report, explained
What the seller's report must cover, who can write it, the 3-month inspection rule and the 180-day reliance limit.
The report often flags decks, pergolas, carports or extensions built without approval. If yours does, an unapproved structure assessment tells you what the structure needs.
Buying, and something in the report worries you? A pre-purchase structural inspection looks at the structure before you sign.
Older homes
What changes when the house is older?
Pre-1985 homes bring asbestos rules into any renovation, and the 1960s govvie has its own quirks.
Older homes and asbestos in the ACT
The asbestos removal control plan for pre-1985 homes, and the difference between the Mr Fluffy Register and List.
RenovationRenovating a 1960s ex-govvie
Brick veneer, the 400 Series and the walls people want gone: what to check before you renovate or extend.
New blocks and projects
Building new, adding a dwelling or rebuilding?
The rules and engineering behind granny flats, knock-down rebuilds, building near mains and building on new-estate blocks.
Granny flats and dual occupancy in the ACT
What the Missing Middle reforms allow from 1 July 2026, and the 90 m² limit for a secondary residence.
New buildKnock-down rebuilds in Canberra
Demolition, asbestos, trees, utilities and footings: the approvals checklist for rebuilding on your block.
SewerBuilding near a sewer in Canberra
Building near an Icon Water main or over a private drain: what needs approval and what the engineering involves.
New buildBuilding on a new estate block in Canberra
Controlled fill, shallow rock and steep slopes: what the published reports on new-estate blocks show.
General information, dated 6 November 2026
Every guide was written on 6 November 2026 from official sources, listed at the end of each guide with nofollow links. ACT rules change. The Missing Middle Housing bill passed on 21 October 2026 but wasn't in force when we wrote these guides, and NCC 2025 becomes mandatory for building approvals from 1 May 2027. Check the current position before you rely on a rule, and ask your certifier.
Ready to price a job? See all home services and prices, or send photos or plans for a fixed quote in under 20 minutes on average, during business hours.
Get a fixed quoteAbout these guides
Something else on your mind? Call 02 6189 9876, email info@canberrastructuralengineers.com.au or send photos for a fixed quote.
Are these guides advice for my house or block?
No. They're general information for Canberra and the ACT, written on 6 November 2026 from official sources. For your own house or block, send photos or plans and we reply with a fixed quote in under 20 minutes on average, during business hours.
Do the guides cover Queanbeyan, Jerrabomberra and Googong?
Mostly no. The guides explain ACT rules. The three NSW areas follow NSW law and Queanbeyan-Palerang Regional Council. See our Queanbeyan page for how we work there.
Which rules are about to change?
Two to watch. The Planning (Missing Middle Housing) Amendment Bill 2026 passed on 21 October 2026 but wasn't in force when we wrote these guides. And from 1 May 2027 new building approvals must use NCC 2025, apart from projects with a development application lodged before 1 November 2026.
Where should I start if I'm not sure what I need?
Start with do I need a structural engineer?. It explains who does what in the ACT and who to call first. Or describe the problem in a few lines and we'll tell you.