The ex-government house is Canberra’s signature dwelling. Built by the National Capital Development Commission and its predecessors between roughly 1950 and 1975 to house a rapidly expanding public service, these houses were constructed to standard plans, on generous blocks, in suburbs laid out with a genuine planning intelligence — Ainslie, Yarralumla, Deakin, Curtin, Narrabundah, Lyneham, Hughes, Pearce, Farrer.
A related guide to consider while planning this work is Adding Underfloor Heating to an Existing House: Electric vs Hydronic.
They are small, solidly built, thermally dreadful and sitting on some of the best residential land in the country. They are also the single largest renovation opportunity in Canberra, and the Missing Middle Housing Reforms that commenced on 1 July 2026 have made many of the blocks they sit on considerably more valuable.
What You Are Actually Buying
The typical construction
- Double brick or brick veneer, depending on the era and the plan. Earlier houses are more often double brick; later ones brick veneer on a timber frame.
- Concrete tile or corrugated steel roof, usually on a simple hip or gable at a modest pitch
- Timber floors on bearers and joists over a ventilated subfloor in the earlier stock; concrete slab in some later houses
- Single-glazed timber or early aluminium windows, small by modern standards and often poorly oriented
- Minimal or no wall insulation, and ceiling insulation that is either absent, thin, or has been added at some point and compressed
- Compartmentalised plan — separate kitchen, separate living, three bedrooms, one bathroom, a separate toilet
- Around 90 to 130 square metres of floor area on a block of 700 to 1,000 square metres
- Original electrical and plumbing, frequently including ceramic fuse boards and galvanised water pipe
The essential character of the type is that the block is generous, the house is small, the bones are sound and the performance is poor. That combination is what makes them such good renovation projects.
Loose-Fill Asbestos: Check This First
Before anything else, before a designer, before a builder, before an offer if you can manage it.
- Loose-fill amosite asbestos insulation was installed in more than 1,000 Canberra homes during the 1960s and 1970s. A small number contain crocidolite, which is more hazardous.
- A removal program ran from 1988 to 1993, but material remained in wall cavities, subfloor spaces and behind cornices
- The ACT government has run an eradication scheme involving acquisition and demolition of affected houses, and government officials have acknowledged that loose-fill material is probably still present in the community
- Engage a licensed asbestos assessor before any work opens a wall cavity, ceiling space or subfloor. A standard building inspection does not cover this.
- The ACT Loose Fill Asbestos Coordination team holds information on affected properties, and Access Canberra can be contacted on 13 22 81
- A support scheme exists for people with asbestos-related disease connected to affected properties
The assessment costs a few hundred to a few thousand dollars. Disturbing loose-fill asbestos during a renovation contaminates the house and everything in it, and the consequence is demolition rather than remediation. This is the one thing about renovating in Canberra that has no equivalent anywhere else in Australia, and it is not negotiable.
Separately, bonded asbestos cement sheet is near-universal in this stock — eaves, wet area linings, ceilings, sheds and fences. That is a routine licensed removal at $60 to $120 per square metre, and it is a different and far less serious problem.
The Thermal Problem
Canberra has the coldest winters and among the hottest summers of any Australian capital, with sub-zero mornings, heavy frosts and 35 to 40 degree afternoons in the same year. An unmodified ex-government house handles neither.
Where the performance goes
- Uninsulated walls. Double brick has mass and essentially no thermal resistance. Brick veneer has a cavity that was never filled.
- Ceiling insulation absent, thin or displaced, and frequently wet where an exhaust fan has been venting into the roof space.
- Single glazing in conductive frames. Early aluminium frames are thermal bridges and the glass is a hole in the wall.
- Enormous air leakage — gaps around doors and windows, unsealed floorboards, open chimneys, unsealed downlights and exhaust penetrations, and a ventilated subfloor connected to the interior through every gap in the floor.
- No thermal mass usefully placed. In a double brick house the mass is on the outside of nothing.
- Poor orientation. Many plans were repeated across a suburb without regard to which way the block faced.
What fixing it costs, in priority order
- Ceiling insulation to R6.0 or better: $3,000 to $6,000. The single highest return in the house.
- Comprehensive draught sealing: $2,000 to $4,000 — doors, windows, floorboards, chimneys, downlights, exhaust penetrations, the subfloor connection.
- Underfloor insulation to suspended timber floors, maintaining subfloor ventilation: $4,000 to $9,000. Genuinely worthwhile in this climate.
- Wall insulation. Brick veneer cavities can often be injected — $4,000 to $10,000. Double brick requires furring out and lining the internal face with a ventilated cavity, at $180 to $300 per square metre of wall, which reduces room dimensions but also creates a service cavity.
- Double glazing: $1,000 to $2,200 per square metre installed, in thermally broken frames. In Canberra this is one of the few Australian markets where the payback is defensible on energy alone, and the comfort difference is dramatic.
- Heavy lined curtains with pelmets as an interim measure, which are genuinely effective and inexpensive.
Budget $30,000 to $90,000 for a proper envelope upgrade on an ex-government house, and understand that in the ACT it is directly reflected in the Energy Efficiency Rating disclosed at sale and lease. The detail is in energy efficiency upgrades and rebates for Canberra homes.
The Plan: What to Change
The characteristic ex-government floor plan is a set of small rooms off a central passage, with the kitchen at the back facing the service yard and the living room at the front facing the street. In most cases the street is south or east of the living room, which is exactly wrong.
The standard move
- Extend to the north or north-east with a new open living, dining and kitchen space that opens to the garden
- Convert the original living room to a bedroom, study or second living space
- Take the original kitchen for a laundry, mudroom or second bathroom
- Keep the bedroom wing largely as it is, upgrading the envelope and the joinery
- Add a second bathroom or ensuite within the existing footprint where possible
This move is repeated across Canberra because it works. It respects the existing structure, it fixes the orientation, and it delivers exactly what buyers of these houses want.
A related guide to consider while planning this work is How Much Does a Home Renovation Cost in Canberra? A 2026 Price Guide.
What to keep
- The generous ceiling heights in the better-quality plans
- Original brickwork where it is sound — the face brick of this era ages well and is worth exposing rather than rendering
- Solid timber joinery and doors, which are better than modern replacements and can be stripped and repainted
- Timber floors, which are usually good hardwood under the carpet and sand back beautifully
- The subfloor, which is a genuine asset — it gives you somewhere to run services and to insulate from below
- The mature garden. Canberra’s suburban trees are protected, valuable and irreplaceable.
Structure and Services
Removing walls
In a double brick house the internal walls are frequently load-bearing. Each structural opening needs an engineer’s design, a steel beam, temporary propping and adequate footings — $11,000 to $24,000, more where the span is long. In a brick veneer house the internal walls are timber-framed and the picture is easier, but the external skin still needs support at any new opening.
Footings
- Rock is common across much of Canberra. Hitting it at 600 millimetres changes the footing cost from excavation rates to rock breaking rates — commonly three to eight times higher.
- Reactive clay in parts of Tuggeranong, Belconnen and Gungahlin requires an engineered footing system.
- Frost is not a footing design issue at Canberra’s depths, but it does affect exposed slabs, paving and external plumbing.
- Get the geotechnical investigation before finalising any design. On a Canberra extension it is the largest single budget variable.
Services
- Rewire. Anything with a ceramic fuse board and rubber-insulated wiring needs a full rewire — $10,000 to $22,000 — and it is far cheaper while walls and ceilings are open.
- Replumb. Galvanised water pipe is at end of life. Replacing it also lets you insulate and lag pipework properly, which matters here in a way it does not further north — frozen and burst pipes in an unheated subfloor are a real Canberra event.
- Go all-electric. The ACT is transitioning away from fossil fuel gas, and an all-electric renovation is the sensible default. Reverse-cycle for heating and cooling, heat pump hot water, induction cooking. Check the switchboard capacity early.
- Hydronic underfloor heating suits this climate exceptionally well, and where a new slab is going in for an extension the marginal cost is modest. Retrofitting it to a suspended timber floor is harder but possible.
The Missing Middle Question
Since 1 July 2026, an RZ1 block in an established Canberra suburb can support missing middle housing up to two storeys — duplexes, terraces and small-scale multi-dwelling development. RZ2 blocks can go to three storeys. The former minimum block size for a second dwelling in RZ1 has been removed, unit titling thresholds have been relaxed, and a 50 per cent partial waiver on the Lease Variation Charge applies to eligible development until June 2029.
For an owner of an ex-government house on a 700 to 1,000 square metre block, that changes the question. The options are now:
- Renovate and extend the existing house, keeping the whole block
- Retain and extend the house, and add a second dwelling — with the lease variation and the reduced Lease Variation Charge
- Demolish and build two or more dwellings, potentially unit titled and separately saleable
The arithmetic on those has changed materially and it is worth running properly before committing to a straightforward renovation. See knockdown rebuild versus renovate in Canberra and granny flats and second dwellings in Canberra.
Approvals
- Read the Crown lease. All ACT land is leasehold and the purpose clause governs use. A single-dwelling renovation on a single-dwelling lease needs no variation; adding a dwelling does.
- A compliant single-dwelling extension that meets all the development controls and the essential design elements can be exempt from a development application — but it still needs building approval and a building commencement notice from a private certifier.
- Trees. Registered trees and trees in the Tree Management Precinct are protected, including their root zones. Get an arborist report before the design is drawn.
- Heritage. Some Canberra precincts and individual houses are on the ACT Heritage Register, and parts of the inner north and inner south are affected.
- Bushfire, on the western and southern fringes.
The Budget and the Sequence
A full ex-government house renovation with a rear addition realistically runs $550,000 to $1.3 million in 2026, of which $100,000 to $250,000 is remediation and envelope work before anything a buyer can see improves.
The order that works
- Loose-fill asbestos assessment before anything else
- Crown lease review, zone check and arborist report
- Geotechnical investigation and site classification
- Existing Energy Efficiency Rating assessment, with modelled improvements
- Design, including the decision on whether the Missing Middle reforms change the brief
- Bonded asbestos removal and demolition
- Structural work and footings
- The extension, to a high envelope standard
- Services throughout — rewire, replumb, all-electric conversion
- Envelope upgrade to the retained house — insulation, glazing, draught sealing
- Internal finishes and joinery
- Landscaping
These houses reward a renovation that fixes the two things they got wrong — orientation and thermal performance — and leaves alone the things they got right, which are the block, the bones and the location. A renovation that spends the whole budget on a kitchen and leaves the house cold is a common and expensive mistake in this city.
For the surrounding cost picture see the Canberra renovation cost guide, and for the extension itself, home extensions in Canberra.
What These Houses Are Actually Worth Keeping
The temptation with an ex-government house is to treat it as a shell — strip everything and start again inside the walls. That is usually a mistake, because several things about this stock are better than what would replace them.
- The hardwood floors. Almost every one of these houses has good hardwood under the carpet. Sanded and finished at $50 to $90 per square metre, it outperforms anything you would lay in its place, and it is one of the highest visual returns available in a Canberra renovation.
- The face brickwork. The brick of this era is generally sound, well laid and ages well. Rendering over it is usually a mistake both aesthetically and thermally, and it is expensive to reverse.
- Solid timber doors and joinery. Heavier and better proportioned than modern equivalents. Strip and repaint rather than replace; the replacements never match the profiles.
- Ceiling heights, which in the better plans are more generous than a modern volume-built house.
- The subfloor. A genuine asset — somewhere to run and insulate services, and somewhere to insulate the floor from below without losing room height.
- The block and the garden. Mature protected trees, established planting and a generous setback pattern that no new subdivision offers.
- The proportions of the original rooms, which are modest but well judged. Not every wall needs to come out.
The things worth changing are the orientation, the thermal envelope, the services and the wet areas. The things worth keeping are the fabric, the floors, the brick and the garden. Projects that get this the wrong way round spend more and produce less.
The Sequence in Detail
Order matters more on this housing type than on most, because several of the steps foreclose others.
Before you buy
- Loose-fill asbestos assessment by a licensed assessor
- Crown lease review — the purpose clause
- Zone, development controls and canopy cover requirement
- Arborist report mapping protected trees and root zones
- Geotechnical investigation for rock and reactive clay
- Existing Energy Efficiency Rating
- Building inspection covering roof, wiring, plumbing, subfloor and structure
Design stage
- Decide the fundamental question first — renovate, renovate and add a second dwelling, or redevelop. The Missing Middle reforms changed this and the answer is no longer automatic.
- Set the northern extension position using the arborist report and the canopy cover requirement as inputs
- Model the envelope improvements against the existing rating so the budget is evidence-based
- Engage the certifier at concept, not at lodgement
- Ask the designer what it would take to stay inside the exempt development criteria
Construction stage, in order
- Tree protection fencing before any plant arrives on site
- Bonded asbestos removal and clearance
- Demolition of the rear service areas
- Footings — with the rock allowance and any underpinning
- Frame, roof and windows, sequenced to be weathertight before the end of May
- Rewire and replumb throughout, with pipe lagging in every unheated space
- Insulation and sealing — ceiling, walls, underfloor — across both the new work and the retained house, photographed before it is covered
- Linings, wet areas and waterproofing, with cure times respected
- Joinery, stone, painting, flooring
- Heating commissioned and balanced
- Landscaping, and an updated Energy Efficiency Rating at completion
The step most often skipped is the envelope work to the retained house, because it happens mid-project when the budget is under pressure and it produces nothing visible. It is also the step that determines whether the finished house is a pleasure to live in or an expensive disappointment every July.