Missing Middle housing
Townhouse, dual occupancy and multi-unit engineering in Canberra
Since 1 July 2026, RZ1 blocks can take duplexes, terraces and townhouses of up to two storeys. We design the footings, shared walls, retaining and frames, and document them for your certifier and builder.
- Fixed quote per project, from your photos or plans
- Fixed quote in under 20 minutes on average, during business hours
- Documented for your builder and certifier
Prefer to talk? Call 02 6189 9876
Or email info@canberrastructuralengineers.com.au
Monday to Friday, 8:00am to 5:00pm
- Engineering onlyWe never sell the repair or the build.
- Fixed quote per projectPriced from your photos or plans before we start.
- Fixed quote in under 20 minutes on averageDuring business hours, Monday to Friday.
- Canberra and the Queanbeyan sideEvery district, plus Queanbeyan, Jerrabomberra and Googong.
In short
Townhouse and multi-unit engineering in Canberra is a fixed quote per project, ex GST. Since the Missing Middle reforms started on 1 July 2026, RZ1 allows duplexes, triplexes, terraces, townhouses and low-rise apartments of up to two storeys, and RZ2 up to three. A block going to two or more dwellings can't use the DA exemptions. We design footings, shared walls, retaining and frames for your certifier.
- Fee
- Fixed quote per project, ex GST with inc GST beside
- Quote
- Fixed, in under 20 minutes on average, during business hours
- You receive
- Footing, slab, retaining and framing details for your certifier
- Storeys
- Up to 2 in RZ1 and 3 in RZ2 for multi-unit housing
- Site coverage
- 45% of the original block for multi-unit housing in RZ1 and RZ2
- Developer licence
- Needed for 3 or more dwellings since 1 October 2026
What did the Missing Middle reforms change for townhouses?
They opened RZ1 blocks to more than one or two homes. Major Plan Amendment 04 started on 1 July 2026, and its numbers shape the engineering from the first sketch.
| Rule | What it says from 1 July 2026 |
|---|---|
| Housing types in RZ1 | Duplexes, triplexes, terrace homes, townhouses and low-rise apartments |
| Storeys | Up to 2 in RZ1; up to 3 for multi-unit housing in RZ2 |
| Site coverage | 45% of the original block for multi-unit housing in RZ1 and RZ2 |
| Subdivision | RZ1 blocks can be subdivided without first building a dwelling, if minimum block sizes are met |
| Lease Variation Charge | 50% off for eligible RZ1 and RZ2 projects that defer the charge on or after 10 June 2026, get development approval by 30 June 2029 and finish by 31 December 2030 |
Territory Plan 2023 and the ACT Government's Missing Middle housing reforms page, checked 6 November 2026. Minimum block sizes and full eligibility rules: check with your designer and the planning authority.
Two storeys and 45% coverage on one block usually mean homes that share walls. Footings under a shared wall carry both homes, so the footing design has to work for each side. The full planning rules, granny flats included, are in our guide to granny flats and dual occupancy in the ACT.
What approvals does a townhouse or dual occupancy project need?
Development approval and building approval, and from three dwellings a property developer licence. A block that goes to two or more dwellings can't use the ACT's DA exemptions.
| Project | What applies |
|---|---|
| 2 dwellings (a duplex or dual occupancy) | Development approval from the Territory Planning Authority, then building approval from a licensed certifier |
| 3 or more dwellings | Development and building approval, plus a property developer licence (since 1 October 2026). Selling off the plan needs the licence from 1 April 2027. The Registrar can issue rectification orders for serious defects up to 10 years after completion. |
| Residential building insurance | Applies to class 1 and class 2 buildings of no more than 3 storeys |
If an existing house comes down first, demolition of a single dwelling is DA-exempt only with no shared party wall and written notice to the neighbours before it starts. A dilapidation report on the houses next door records their condition before excavation begins. No ACT law requires one.
Adding one granny flat, or a second home behind your own? Our page on granny flat and dual occupancy engineering covers that. This page is for projects that build two or more new homes at once.
What's included in townhouse and multi-unit engineering?
Engineering for the whole structure, documented for your certifier and builder. Your fixed quote says if a site visit is needed.
Site classification and footings
A site classification for the block, then footing and slab design to suit it. Published reports for new-estate blocks show one block can range from rock to deep clay, and cut or fill means the class must be reassessed. See footing design and site classification.
Shared walls
Footings under the walls two homes share, and the framing details that tie each side in, set out so your builder can build each dwelling from the drawings.
Stepped sites and retaining
Townhouses on a slope often step down the block, with retaining between levels. Over 1.2 m, measured from the top of the wall to the lowest ground beside it, design and construction standards apply. See retaining wall engineering.
Sewer and stormwater mains
Icon Water's guidance says its approval comes before building work near its assets, and footings stay out of the pipe protection envelope. We design footings to suit. See building near sewer and stormwater mains.
Frames, beams and tie-downs
Framing, bracing, tie-downs and fixings, and any steel or concrete members, detailed for the certifier's stage inspections.
Low-rise apartments
Certifiers lodge class 2 to 9 building approvals against the 2019 minimum documentation guide. We prepare the structural drawings and calculations for that lodgement.
What sets the fixed quote: the number of dwellings and storeys, the slope and soil, how much retaining the site needs, any mains crossing the block, and how many drawings your certifier needs.
We're engineers only. We don't build, sell or recommend builders, so the design isn't tied to anyone's contract.
Where are Canberra's townhouses?
In the newer districts. In the 2021 Census, 23.8% of occupied homes in the Molonglo Valley and 20.5% in Gungahlin were semi-detached, row or townhouse dwellings, the two highest shares in Canberra.
Newer suburbs also mean sloping blocks. Builders describe estates such as Jacka, Whitlam and Denman Prospect as hilly, so townhouses there may need to step down the slope, with retaining between levels.
Local detail is on our pages for Gungahlin and the Molonglo Valley.
Semi-detached, row and townhouse dwellings, 2021
What happens next?
Three steps, and you know the price before anything is booked.
Send plans
Use the form above or email info@canberrastructuralengineers.com.au. Your designer's plans, or a site plan and sketch. Add up to 5 files.
Get a fixed quote
We reply with a fixed quote in under 20 minutes on average, during business hours, ex GST with the inc GST figure beside.
Design and drawings
We classify the site and design the structure, then send drawings and calculations for your certifier and builder.
Multi-unit work is priced per project. Our home services have published prices, and the rest of the lane is on commercial structural engineering.
Get a fixed quoteSmaller projects, and the planning rules in full
Every service is quoted at a fixed price before we start. Send photos or plans and we reply in under 20 minutes on average, during business hours.
Granny flats & dual occupancy
Slab, footing, frame and retaining engineering for a secondary residence or a second home on your block.
Fixed quotefrom your photos or plans See the serviceGranny flats and dual occupancy in the ACT
What the Missing Middle reforms changed on 1 July 2026, the secondary residence rules, which approvals a second home needs, and the engineering it usually involves.
Read the guide
Building on a new estate block in Canberra
What published site reports reveal about fill, reactive clay and shallow rock on new blocks, how slopes and boundary limits shape the design, and the protections that come with a new home.
Read the guideTownhouse and multi-unit questions
Something else on your mind? Call 02 6189 9876, email info@canberrastructuralengineers.com.au or send photos for a fixed quote.
Can I build townhouses on an RZ1 block in Canberra?
Since 1 July 2026, yes, within the Territory Plan rules. RZ1 now allows duplexes, triplexes, terrace homes, townhouses and low-rise apartments of up to two storeys, with multi-unit site coverage of 45% of the original block. Your designer checks your block against the rules.
Do I need a property developer licence to build three townhouses?
A property developer licence has been needed since 1 October 2026 for projects of 3 or more dwellings, and it's needed to sell off the plan from 1 April 2027. Check the scheme's details on the ACT planning website before you commit.
Who gets the 50% Lease Variation Charge reduction?
Eligible RZ1 and RZ2 projects that defer the charge on or after 10 June 2026, get development approval by 30 June 2029 and finish by 31 December 2030. Confirm your project's eligibility with the planning authority.
Is a granny flat the same as a dual occupancy?
No. A granny flat is a secondary residence: up to 90 m², one per block, and only with a single dwelling. A dual occupancy is two dwellings on one block, which this page covers along with townhouses.
How much does townhouse engineering cost?
It's a fixed quote per project, ex GST with the inc GST figure beside. The number of dwellings and storeys, the slope and soil, any retaining, mains on the block and the drawings your certifier needs set the price.