Home Extensions · Guildford NSW 2161
Home extensions in Guildford, done properly.
Home extensions in Guildford by a licensed builder, from timber cottages that need a proper rear addition to brick homes that need more room. 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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Building out the back
Adding space to a Guildford cottage.
Strava Group builds house extensions in Guildford: new rear living areas, extra bedrooms, bathrooms and covered outdoor rooms. Guildford’s older streets mix weatherboard cottages with face brick ones, and many have a skillion addition on the back from decades ago. Those older additions are rarely worth keeping. The extension replaces them with a properly footed, insulated and flashed rear section that joins the house cleanly.
Extensions we build for Guildford homes:
- Rear extensions replacing old additions
- Kitchen, dining and family extensions
- Extra bedrooms and bathrooms
- Weatherboard and fibro cladding matched
- Covered decks and outdoor rooms
- Laundries moved out of the kitchen
- Subfloor levelling at the join
- Insulation upgrades through the old wall
If the cottage has enough room and needs work inside, see home renovations in Guildford. For more space without losing the yard, second storey additions are the alternative, though a timber cottage needs careful assessment first.
Timber houses are the easiest to extend well. New weatherboards can follow the old profile, the frame can be opened up without cutting brick, and with the right detail at the join, nobody can tell where the original house stops.
Quick Answer
Most home extensions in Guildford 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. Removing an old rear addition, testing and removing fibro and levelling the floor at the join add the most to a typical Guildford quote.
Local knowledge
What we know about extending in Guildford.
Guildford extensions mostly start from older, lighter houses. Here is what that means on site.
Council
Guildford falls under Cumberland City Council and the Cumberland LEP 2021. The LEP lists 8 heritage items in the suburb, and a property holding one needs a Development Application with a heritage assessment. Outside those, many rear extensions can use Complying Development through a private certifier. Controls are on the Cumberland City Council site and the NSW Planning Portal.
Housing stock
Weatherboard cottages sit alongside brick homes of several eras, and many have been added to at least once. We check what each previous addition stands on before deciding whether the new work attaches to it or replaces it.
Cladding and fibro
On a weatherboard house, new boards can follow the existing profile closely, so the extension reads as part of the original. Fibro is different. Sheeting installed before the 2003 national ban may contain asbestos, so we test it before any cutting, and where the old sheet has to go, a licensed contractor removes it.
Floors and footings
Many cottages here sit on piers with timber floors that have dropped over the years. Before connecting, we level the old floor at the junction, then build the extension on engineered footings set to the same height, so there is no lip or slope where the rooms meet.
Block and services
Older blocks often have the sewer line crossing the rear yard and a single narrow side path. We locate the sewer before design, since building near it needs Sydney Water approval, and we plan deliveries and machinery around the access so it is costed from the first quote.
A typical extension
A rear addition of 20 to 40 square metres in place of the old skillion section: kitchen and family room across the back, a bathroom and laundry beside them, and a deck or covered area stepping down to the yard.
Start here
Tell us about your Guildford 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 Guildford 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 Guildford.
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 Guildford the lighter timber and fibro homes are simpler to open up, but removing old additions, asbestos and floor levelling at the join add up. Most projects sit in the lower to middle part of the band. Wet areas and how much of the existing structure has to change account for most of the remaining difference between a modest and a large project.
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
Guildford 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 Guildford.
We build extensions across the Cumberland area and the surrounding western suburbs. Select a suburb for local council information and what extensions there typically cost.
Cumberland and western Sydney
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 Guildford? We also build second storey additions and home renovations in Guildford.
Extend your Guildford 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 Guildford
Other Strava Group services in Guildford
Each page covers the local council, the homes we see in Guildford and what that kind of project typically costs.