Home Extensions & Additions in Kellyville
Keystone Building has been extending and renovating homes across The Hills district for close to three decades, and Kellyville is one of the suburbs we know best. In building terms, it is really two suburbs in one. There are the older brick homes around The Village and Acres Road, many of them single level on generous established blocks, and there is the newer estate housing stretching towards North Kellyville and Beaumont Hills, where floor plans are large but land is tight. Each of those starting points calls for a very different approach.
We also know how The Hills Shire Council assesses a residential addition, how the shale-derived clay under this part of the ridge changes the way footings are engineered, and how much the suburb's mature tree canopy shapes where new floor area can go. That local knowledge is the difference between a design that moves smoothly through the approval process and one that stalls. It is why Kellyville families trust us with renovations to homes they intend to stay in for decades.
More room for a growing family, without leaving the suburb you chose for its schools, parks and Metro line. Keystone Building has been designing and building Second Storey Additions, Ground Floor Extensions and full home renovations since 1997. Home extensions in Kellyville generally come down to three choices: build up, extend out, or rework the plan you already have. Whichever of the three suits your home, the process is the same: you deal with one local, family-run builder from the first sketch through to final handover.
Second storey additions
For an older single-level home that has run out of room at ground level, Second Storey Additions in Kellyville are usually the most practical answer. Architecturally called a first floor addition, another storey can add bedrooms, bathrooms and a separate living zone above the existing structure, while the yard, pool and side access stay exactly as they are.
The build begins with a structural engineer confirming that the existing slab and footings can carry the load, after which the roof comes off and the structure below is reinforced. On a compact estate block with nowhere left to extend outwards, building up is often the only way to gain genuine floor area.
Ground Floor Extensions
Ground Floor Extensions in Kellyville most often open the back of the house to the garden, adding a larger kitchen and living area, a covered alfresco, a guest bedroom or a self-contained space for a parent or an adult child. Everything stays on one level, so no floor area is lost to a staircase, and access remains step-free for every age in the household. Done well, a Ground Floor Extension also lifts the resale value of the property.
Major home renovations
Complete home renovations in Kellyville are rarely about square metres. Many local houses already have the floor area but not the layout. A full renovation reworks the plan itself, removing the walls that close the kitchen off from the living spaces, drawing daylight deeper into the house, and rebuilding kitchens, bathrooms and laundries to a standard that matches the rest of the street. It is often the most cost-effective way to modernise a 1990s or early-2000s home without touching its footprint.
Design & Council approvals
One team, start to finish. Concept design, engineering, structural drawings, certification and The Hills Shire Council approvals are all handled in-house, so you are never coordinating separate consultants or chasing paperwork between them.
Two very different housing stocks
Older Kellyville homes around The Village sit on established blocks, frequently 700 square metres or more, with room to extend in almost any direction. The estate homes built from the late 1990s onwards are the opposite: they have large floor plans on compact lots, with narrow side setbacks and little spare ground. We establish which of the two you have before proposing anything, because that determines whether the sensible move is up or out.
Shale-derived reactive clay
Much of The Hills ridge sits on soils weathered from Wianamatta shale. These soils behave as reactive clay, swelling and shrinking with the seasons. It is a normal local condition rather than a barrier, but it does mean footings, piers and any structural reinforcement are engineered to your own site classification, not carried over from an assumption about the house next door.
A mature tree canopy
Kellyville's established streets are heavily planted, and The Hills Shire protects that tree canopy through its landscaping and tree management controls. Mature trees influence where an extension can sit, how footings are designed near root zones, and what planting has to be replaced. We map all of this at concept stage, so protecting a favourite tree never forces a redesign late in the process.
Approvals through The Hills Shire Council
Every extension or addition needs the right approval. Depending on the scope and your site, that is either a Complying Development Certificate (CDC) issued by a private certifier or a Development Application (DA) lodged with The Hills Shire Council. Homes in newer estates may also carry design covenants from the original subdivision, and these sit alongside the council controls. We identify the correct pathway at the very start and prepare your plans to meet the relevant requirements, which keeps the approval efficient and your project moving.
Built On Time & Budget
With careful planning, clear communication and realistic scheduling, we keep your home addition on budget and on time (sometimes even earlier, when possible!).
Stay Home While We Build
Staged construction methods mean most families remain in the home throughout the build, saving on rent and storage.
Minimal Disruption
We contain dust, manage noise, tidy up daily and protect your finishes while we work.
Customer-First Approach
Every layout starts with how your family actually lives, and you are involved in every key design decision.
No Hidden Costs
We provide a detailed fixed price building contract that clearly outlines the scope of works and project costs, giving you confidence before construction begins.
Trusted Family Business
Nearly three decades of home extensions, additions and renovations, delivered by a local, family-run team that has been in business since 1997.
Featured Projects
Our Refined Process
We build throughout Kellyville and the surrounding suburbs in and around the Hills District, so wherever you are in the local area, there is a good chance we are already on site nearby.
- Kellyville
- North Kellyville
- Kellyville Ridge
- Beaumont Hills
- Rouse Hill
- Castle Hill
- Baulkham Hills
- Glenhaven
- Bella Vista
- Norwest
- Cherrybrook
- West Pennant Hills
- Dural
- Box Hill
- Annangrove
- Winston Hills
- Kenthurst
- Glenorie
Our service also reaches across Blacktown, Parramatta and Penrith, extending into the wider Western Sydney region, the Hawkesbury and the Blue Mountains.
There is no single square-metre rate, because so much depends on the home we are working with. We give you a free price guide at your first consultation, based on the details you provide, then a detailed fixed price once a site assessment and final plans are confirmed.
The variables that move the figure most are the ones that stay hidden until we inspect: how much structural reinforcement the existing house needs, how tight site access is for machinery and deliveries.. Many clients fund the work through a construction loan that draws down in stages as the build progresses. That is worth raising with your lender before design begins.
Plan for two stages. Design, engineering and council approval can take a few months up front. A Complying Development Certificate is typically assessed in around 20 business days, while a Development Application through The Hills Shire Council generally takes eight to twelve weeks. On site, a Ground Floor Extension usually runs for about twelve weeks, and a Second Storey Addition for twelve to eighteen weeks, depending on the scope of the work and the weather.
Yes, and around 95 per cent of our clients do. The stages that require you to give up a room differ from project to project. A Second Storey Addition takes over the room where the new staircase breaks through, while a renovation is at its most disruptive when the kitchen or the main bathroom is offline. In those cases, a temporary kitchenette or a second bathroom usually keeps daily life running through the few weeks involved.
The Hills Shire regulates the removal and pruning of many trees, and the fact that a tree stands where you want to build is not on its own grounds for taking it out. Where a tree can stay, footings can usually be designed to work around the root zone. Where removal is justified, we prepare the tree removal application as part of your approval package, and replacement planting is generally required as a condition.
Privacy and overshadowing are among the first things assessed on a Second Storey Addition, and among the most common reasons a poorly prepared design gets held up. Upper level windows are positioned, offset or screened so they do not look directly into a neighbour's living areas or private open space, and shadow diagrams are prepared to show that surrounding homes keep the required winter sunlight. Resolving this at the concept stage costs far less than redesigning after a submission.
If you have concept drawings from an architect or draftsperson, we can review them, price them and build from them, or refine them where the design and the construction budget do not line up. If you would rather start with a blank page, our in-house design service covers everything from the first concept through to construction drawings.