Home Extensions · Dundas NSW 2117
Home extensions in Dundas, done properly.
Home extensions in Dundas by a licensed builder who designs around the slope before anything else. Most extensions run $70,000 to $300,000 depending on size and how much of the existing house has to change, itemised quote, honest programme, one builder from concept to handover.
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Extending on a sloping block
Building out on a Dundas slope.
Strava Group builds house extensions in Dundas: living rooms that step out onto decks, additional bedrooms and bathrooms, and rooms that use the fall of the land. Dundas grew from orchard subdivisions in 1902 and 1905, and its hilly streets mean most backyards either fall away from the house or climb behind it. On those blocks the hardest part of an extension sits below floor level: footings, retaining and where the stormwater goes.
Extensions we build for Dundas homes:
- Rear extensions on stepped or suspended floors
- Living areas opening onto new decks
- Extra bedrooms and bathrooms
- Rooms built out over a sloping yard
- Retaining and drainage around the new work
- Storage or a workshop under the new floor
- Structural openings in the rear wall
- Cladding and roofing that tie old and new together
Where the house is the right size and only the inside needs attention, our home renovations in Dundas page applies. Where the yard is too steep to build on economically, second storey additions can be the better route.
A Dundas extension often starts below the floor. On a block that falls away, the new room can sit on piers or a stepped slab with the yard carrying on underneath it, which turns a steep, unused backyard into living space.
Quick Answer
Most home extensions in Dundas run $70,000 to $300,000 depending on size and how much of the existing structure has to change, at roughly $2,500 to $4,500 per square metre for ground floor work, with around $30,000 in preliminaries (design, engineering and council approvals, plus site set-up) on top. Footings and retaining on a sloping block, the stormwater solution and adding a bathroom decide most Dundas budgets.
Local knowledge
What we know about extending in Dundas.
The land shapes almost every Dundas extension. This is what we look at first.
Council
Dundas is in the City of Parramatta Council area under the Parramatta Local Environmental Plan 2023. A detached home can often be extended under Complying Development with a private certifier, and heritage items and site specific controls mean a Development Application. Controls are published by City of Parramatta Council and on the NSW Planning Portal.
Slope and footings
Hilly, sloping streets define Dundas. On a falling block, the extension may need a stepped slab, a suspended timber or steel floor on piers, or retaining walls, and each option prices differently. A site survey and geotechnical report come first, so the engineer designs footings for the real ground.
Stormwater on a fall
Roof water from the new section has to discharge somewhere lawful. A lot that falls toward the street usually drains to the kerb. A lot that falls away from it may need an easement through a downhill neighbour or an on-site system the certifier or council accepts, and we answer that question before design.
Houses, villas and townhouses
Dundas has built up in layers since the early subdivisions, and today about half its dwellings are separate houses, with roughly 40% villas or townhouses. A detached house can be extended with council or certifier approval alone. A villa or townhouse on a strata plan also needs the owners corporation to approve the work.
Levels and machinery
On a slope, the new floor has to meet the existing house exactly while the ground drops away beneath it. We set the levels from the survey, and plan excavation and deliveries around the fall, since a steep side path can mean smaller machines and more hand work.
Space underneath
Where the yard falls far enough, the area beneath a raised extension can become storage, a workshop or a covered outdoor area. The structure is already being built, so enclosing it adds useful space for a modest extra cost.
Start here
Tell us about your Dundas home.
No sales pitch, no obligation. Here is exactly what happens when you enquire:
One at a time, takes about two minutes, so the first conversation is about your project rather than the basics.
The Strava standard
How we build differently.
An extension lives or dies at the junction between old and new. We build for longevity, and on every Dundas extension we run:
Every new-to-existing junction properly detailed
This is where most extensions crack, leak and part company with the house, and the cause is almost always a detailing shortcut. Ours get a proper structural tie, flashing and movement detail.
The existing structure gets rectified first
Where the extension meets the house, we screw off and re-brace the adjoining structure, tying new and old together so the whole building moves as one. Future cracking gets designed out at frame stage instead of patched at the paint stage.
Footings engineered for the ground they sit on
New footings are engineered for your soil and detailed against the existing ones, because differential movement between old and new slabs is the classic extension failure, and it matters more on an older house whose original footings were never engineered to modern standards.
Furring channels for a dead flat finish
Where new ceilings and walls run through to existing rooms, furring channels give one level plane across both, so you cannot see where the house ends and the extension begins.
Waterproofing is a documented hold point
New wet areas are inspected and photographed before a single tile goes on, to AS 3740, and new roof-to-old-roof junctions get the same treatment.
Everything photographed before it is covered
You receive the record at handover, so in ten years you know exactly what is behind your walls and under your floor. Want more than photos? We can also capture a full 3D virtual model of the frame, plumbing, wiring and waterproofing before the plasterboard goes on, available as an optional add-on.
Before starting Strava Group, I spent seven years on the tools as a carpenter and five years running sites. The failures I kept seeing in extensions were always at the join: cracked cornices along the old wall line, roofs that leaked where new met old, floors that stepped as slabs settled differently. None of it was illegal. All of it was avoidable. None of this shows up in a finished-room photo. All of it shows up in year seven.
Honest numbers
What a house extension actually costs in Dundas.
Most builders will not put numbers on a website. We will, because the alternative is wasting your time and ours across three meetings before anyone mentions a figure.
| Item | Typical range |
|---|---|
| Home extension, depending on size and scope | $70k–$300k |
| Ground floor extension work | $2,500–$4,500 /m² |
| Preliminaries, on top of build cost | approx. $30,000 |
Preliminaries are the costs that exist before a single wall moves: design, engineering and council approvals, plus site set-up such as site fencing, temporary services, waste removal, insurances and supervision. They are real, they are unavoidable, and a quote that does not show them separately has either buried them or forgotten them.
In Dundas the slope moves the number more than anything above floor level. Retaining, a suspended floor or deep footings can put even a modest room in the middle of the band. Above floor level, the number to watch is how much of the existing structure has to change.
Every project is quoted properly after a site inspection. These ranges are here so you can decide whether it is worth a conversation.
Good to know
Dundas extension questions.
Rated 5.0 on Google.
We had Strava Group complete major renovation works on our property and were blown away with the quality. The attention to detail and overall finish were amazing.
Great communication, honest work, easy to work with, highly recommend to work with for any new build/renovations. If you are looking to get work done without worrying about shortcuts Strava Group is builder to use.
I highly recommend Strava Group to everyone great workmanship, reliable service, and I couldn’t be happier with the result.
I couldn't be happier with the work from Strava Group. From the beginning, Stav and the team was friendly, honest, and super easy to deal with.
We engaged Strava Group for a home extension and renovation. We are incredibly happy with the service and the results we achieved. From day one Stav and team where always willing to help with any issues we had and we loved that the main focus was as quality and longevity. Highly recommended
Had a great experience with Strava Group. The team was easy to deal with, super professional, and kept me in the loop the whole way through. They really listened to what I wanted and made the whole process feel smooth and stress-free.
Aloona T.
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Nearby
Home extensions near Dundas.
We build extensions across Parramatta and the surrounding suburbs. Select a suburb for local council information and what extensions there typically cost.
Parramatta and surrounds
The Hills District
Hornsby and the Northern Suburbs
Ryde, Hunters Hill and the North Shore
Inner West
Parramatta
Western Sydney
Southern Sydney and St George
Looking for a different service in Dundas? We also build second storey additions and home renovations in Dundas.
Extend your Dundas home properly.
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Tell us about your property and what you want to add. We respond within 24 to 48 business hours with honest advice and real numbers, no cost, no obligation.
More in Dundas
Other Strava Group services in Dundas
Each page covers the local council, the homes we see in Dundas and what that kind of project typically costs.