info@keystonebuilding.com.au
02 4722 5466
5.0
40+ GOOGLE REVIEWS

Ground Floor Additions Blue Mountains

With over 20+ years’ experience in Sydney’s north-west, we transform homes to complement our client’s lifestyles and budgets.

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25 years building ground floor additions across the Blue Mountains, backed by a 5.0-star rating from 40-plus Google reviews. Every Blue Mountains project runs on fixed-price contracts, full licensing and insurance.

A two-storey Hamptons-style home photographed at dusk with warm interior lighting and a wide verandah.

Blue Mountains's Local Home Building Specialists

With over 20 years building across the region, we understand the unique conditions of building in the Blue Mountains — from bushfire-prone zoning to how Blue Mountains City Council assesses a residential addition. That local knowledge helps keep your project moving smoothly through approval.

Our Services in Blue Mountains

More room for a growing Blue Mountains family, without leaving the home they love. Keystone Building has been designing and building second storey additions, ground floor additions and major home renovations since 1997, with one family-run builder seeing every project through from first sketch to final handover.

Second storey additions

Build up with a second storey addition and keep your yard. Architecturally known as a first floor addition, Blue Mountains homeowners choose a second storey extension to add a whole new level of bedrooms, bathrooms and living areas above theirexisting home, without touching the backyard, pool or garden. The build usually starts with a structural engineer confirming your existing foundations can carry a new level, then moves on to removing the existing roof and reinforcing the structure below. For a growing family, it is one of the most popular home additions for gaining room without moving.

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Ground Floor Extensions

Extend your home at ground level. Ground floor extensions Blue Mountains families love to add for single-level living include easy indoor-outdoor flow and step-free access. These ground floor extensions create more space and new living areas for everyday life without adding a staircase, and they can lift the value of your property at the same time.

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Major home renovations

Reimagine the home you have with complete home renovations. Blue Mountains homeowners who want to reconfigure their floor plan to unlock better flow, more light, modern kitchen and bathroom renovations, all finished to a high standard of quality, choose Keystone Building to create lasting value from their existing property

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Design & Council approvals

One team, start to finish. We handle concept design, engineering, structural drawings, certifications and Blue Mountains City Council approvals in-house, so you are never left chasing separate consultants.

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Building in Blue Mountains: What Local Homes Need

Larger, established blocks

Many Blue Mountains homes sit on generous lots of 600 square metres or more. That land is the reason people move here, so wherever it makes sense we build up rather than out, adding living space while leaving the yard, pool and side access exactly as they are.

Reactive clay soils

Pockets across Western Sydney sit on reactive clay that swells and shrinks with the seasons. It is a normal local condition, not a barrier, but it does mean footings and any structural reinforcement are engineered specifically for your site rather than assumed.

Hot summers and BASIX

Keystone holds a 5.0-star rating across more than 40 Google reviews, with feedback from homeowners right across the Blue Mountains LGA who have added a level, extended out or renovated with us.

Home addition & extension approvals

Every home addition or extension requires the right approvals. Depending on your project, this may be through a Complying Development Certificate (CDC) or a Development Application (DA) with Penrith City Council.

We identify the right approval pathway from the start and prepare your plans to meet the relevant planning controls, helping keep the approval process efficient and your project moving forward.

Why Blue Mountains Families Choose Keystone

Adding a top level, extending out or renovating is a big commitment, so the builder you choose matters. As a family-run business, Keystone makes the whole renovation process feel manageable, guiding you through every stage with quality workmanship and a genuine focus on your family's lifestyle. Here is why Blue Mountains families choose us.

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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!).

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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.

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Customer-First Approach

Every layout starts with how your family actually lives, and you are involved in every key design decision.

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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.

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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.

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Our Refined Process

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1. Free introductory session

A relaxed phone call to get to know you, your ideas, your budget and your goals.

2. Free Design Consultation

A site visit where we sit down and talk through every concept of your proposed build.

3. Formal Concept Design and Proposal

A concept plan from a qualified Building Designer, paired with a fixed-price proposal.

4. Plans and Approvals

Architectural and structural drawings prepared and lodged with the relevant authority.

5. Preparing to Extend

We walk you through the pre-construction checklist so you are ready for day one.

6. Construction Phase

The real work begins, and your vision becomes a finished, lived-in home.

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Free introductory session

A relaxed phone call to get to know you, your ideas, your budget and your goals.

Free Design Consultation

A site visit where we sit down and talk through every concept of your proposed build.

Formal Concept Design and Proposal

A concept plan from a qualified Building Designer, paired with a fixed-price proposal.

Plans and Approvals

Architectural and structural drawings prepared and lodged with the relevant authority.

Preparing to Extend

We walk you through the pre-construction checklist so you are ready for day one.

Construction Phase

The real work begins, and your vision becomes a finished, lived-in home.

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Map highlighting the western and southwestern suburbs of Sydney, Australia, including areas like Penrith, Liverpool, Parramatta, and Campbelltown with major roads and surrounding regions.

Areas We Serve in the Blue Mountains LGA

We build throughout the Blue Mountains and surrounding suburbs, so wherever you are in the local area there is a good chance we are already working nearby.

5.0
40 REVIEWS ON GOOGLE

Our Happy Customers

Keystone holds a 5.0-star rating across more than 40 Google reviews, with feedback from homeowners right across the Blue Mountains LGA who have added a level, extended out or renovated with us.

  • "To everyone who is reading this with intention to build a first floor addition, your search should end here.”
    Andrea
    NSW
  • "Thank you so much for all your dedicated hard work and especially your consideration to our family during the renovation of our home.”
    Tracey, Jason, Liam & Mackenzie Brown
    NSW
  • “All the tradesman involved in the renovation process were prompt, courteous and very meticulous.”
    Cathy & Stephen Bone
    NSW
  • "Their workmanship is second to none that I have seen and the service and tradespeople they used were fantastic."
    Reginald Moodley
    Penrith
  • "The staff was very friendly and kept our premises spotless and clean. Nothing was too difficult or out of their way. "
    Neil Moodley
    Glenmore Park
  • "The whole process was professional, on time and on budget. The tradesmen were all brilliant and meticulous.”
    Chris and Jim
    Harrington Park
"Their workmanship is second to none that I have seen and the service and tradespeople they used were fantastic."
Reginald Moodley
Penrith
"The staff was very friendly and kept our premises spotless and clean. Nothing was too difficult or out of their way. "
Neil Moodley
Glenmore Park
"The whole process was professional, on time and on budget. The tradesmen were all brilliant and meticulous.”
Chris and Jim
Harrington Park
"To everyone who is reading this with intention to build a first floor addition, your search should end here.”
Andrea
NSW
"Thank you so much for all your dedicated hard work and especially your consideration to our family during the renovation of our home.”
Tracey, Jason, Liam & Mackenzie Brown
NSW
“All the tradesman involved in the renovation process were prompt, courteous and very meticulous.”
Cathy & Stephen Bone
NSW
"Their workmanship is second to none that I have seen and the service and tradespeople they used were fantastic."
Reginald Moodley
Penrith
"The staff was very friendly and kept our premises spotless and clean. Nothing was too difficult or out of their way. "
Neil Moodley
Glenmore Park
"The whole process was professional, on time and on budget. The tradesmen were all brilliant and meticulous.”
Chris and Jim
Harrington Park
"To everyone who is reading this with intention to build a first floor addition, your search should end here.”
Andrea
NSW
"Thank you so much for all your dedicated hard work and especially your consideration to our family during the renovation of our home.”
Tracey, Jason, Liam & Mackenzie Brown
NSW
“All the tradesman involved in the renovation process were prompt, courteous and very meticulous.”
Cathy & Stephen Bone
NSW
"Their workmanship is second to none that I have seen and the service and tradespeople they used were fantastic."
Reginald Moodley
Penrith
"The staff was very friendly and kept our premises spotless and clean. Nothing was too difficult or out of their way. "
Neil Moodley
Glenmore Park
"The whole process was professional, on time and on budget. The tradesmen were all brilliant and meticulous.”
Chris and Jim
Harrington Park
"To everyone who is reading this with intention to build a first floor addition, your search should end here.”
Andrea
NSW
"Thank you so much for all your dedicated hard work and especially your consideration to our family during the renovation of our home.”
Tracey, Jason, Liam & Mackenzie Brown
NSW
“All the tradesman involved in the renovation process were prompt, courteous and very meticulous.”
Cathy & Stephen Bone
NSW
"Their workmanship is second to none that I have seen and the service and tradespeople they used were fantastic."
Reginald Moodley
Penrith
"The staff was very friendly and kept our premises spotless and clean. Nothing was too difficult or out of their way. "
Neil Moodley
Glenmore Park
"The whole process was professional, on time and on budget. The tradesmen were all brilliant and meticulous.”
Chris and Jim
Harrington Park
"To everyone who is reading this with intention to build a first floor addition, your search should end here.”
Andrea
NSW
"Thank you so much for all your dedicated hard work and especially your consideration to our family during the renovation of our home.”
Tracey, Jason, Liam & Mackenzie Brown
NSW
“All the tradesman involved in the renovation process were prompt, courteous and very meticulous.”
Cathy & Stephen Bone
NSW
"Their workmanship is second to none that I have seen and the service and tradespeople they used were fantastic."
Reginald Moodley
Penrith
"The staff was very friendly and kept our premises spotless and clean. Nothing was too difficult or out of their way. "
Neil Moodley
Glenmore Park
"The whole process was professional, on time and on budget. The tradesmen were all brilliant and meticulous.”
Chris and Jim
Harrington Park
"To everyone who is reading this with intention to build a first floor addition, your search should end here.”
Andrea
NSW
"Thank you so much for all your dedicated hard work and especially your consideration to our family during the renovation of our home.”
Tracey, Jason, Liam & Mackenzie Brown
NSW
“All the tradesman involved in the renovation process were prompt, courteous and very meticulous.”
Cathy & Stephen Bone
NSW
"Their workmanship is second to none that I have seen and the service and tradespeople they used were fantastic."
Reginald Moodley
Penrith
"The staff was very friendly and kept our premises spotless and clean. Nothing was too difficult or out of their way. "
Neil Moodley
Glenmore Park
"The whole process was professional, on time and on budget. The tradesmen were all brilliant and meticulous.”
Chris and Jim
Harrington Park
"To everyone who is reading this with intention to build a first floor addition, your search should end here.”
Andrea
NSW
"Thank you so much for all your dedicated hard work and especially your consideration to our family during the renovation of our home.”
Tracey, Jason, Liam & Mackenzie Brown
NSW
“All the tradesman involved in the renovation process were prompt, courteous and very meticulous.”
Cathy & Stephen Bone
NSW
"Their workmanship is second to none that I have seen and the service and tradespeople they used were fantastic."
Reginald Moodley
Penrith
"The staff was very friendly and kept our premises spotless and clean. Nothing was too difficult or out of their way. "
Neil Moodley
Glenmore Park
"The whole process was professional, on time and on budget. The tradesmen were all brilliant and meticulous.”
Chris and Jim
Harrington Park
"To everyone who is reading this with intention to build a first floor addition, your search should end here.”
Andrea
NSW
"Thank you so much for all your dedicated hard work and especially your consideration to our family during the renovation of our home.”
Tracey, Jason, Liam & Mackenzie Brown
NSW
“All the tradesman involved in the renovation process were prompt, courteous and very meticulous.”
Cathy & Stephen Bone
NSW
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FAQs

Find answers to the most common questions you may have.

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How much does a ground-floor addition cost in the Blue Mountains?

The price depends on the size you choose, the design you select, and the finishes you prefer, but we provide a clear, fixed-price quote so you know exactly what to expect.

Do I need council approval for a single-storey extension?

Yes. We handle all approvals and engineering documentation on your behalf.

Can we live in our home during the build?

Yes, in most cases, families can remain at home while work is carried out.

How long do ground-floor renovations take?

Most projects take a few months, depending on complexity and weather conditions.

Can I include a new kitchen or bathroom in my extension?

Yes, we integrate kitchen and bathroom renovations with ground-floor additions.

5.0
40+ GOOGLE REVIEWS

Talk to Sydney's Home Renovation Specialists

Every Keystone project starts with a free, no-obligation consultation, a relaxed conversation about what you want your Ground Floor Additions Blue Mountains home to become. We will walk you through the whole journey, from the first design idea to council approval and the construction schedule that follows. There is no pressure and no cost to find out what is possible. Give us a call on 02 4722 5466 or request a quote online to get started.

Get a free consultation and quote with no obligation.
Share your plans and speak directly with our team.
Ask questions about timing, approvals, or next steps.
info@keystonebuilding.com.au
02 4722 5466
Unit 1, 29 Coombes Drive, Penrith 2750
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