Home Extensions Southern Highlands
Exceptional Homes. Enduring Craftsmanship.
Trusted in the Southern Highlands for over 30 years.
Why Choose Us
The KMI Difference — Built on Trust, Craft and Experience
01
Three Decades of Local Expertise
More than 30 years building across the Southern Highlands means we understand this land, its climate and its architecture better than any Sydney builder ever could.
02
Award-Winning Craftsmanship
Recognised by the Master Builders Association of NSW for excellence in sandstone work and structural timber craftsmanship on every project we complete.
03
Featured in National Media
Our work has been celebrated in Home Beautiful, Belle and Country Style magazines, a reflection of the distinction we bring to every build.
04
Same Trusted Trades, Every Time
We engage the same core team of master trades professionals on every project, ensuring consistent, uncompromising quality from start to finish.
05
A Personal, Considered Approach
Every home begins with a genuine conversation, never a template, tailored entirely to your lifestyle, your land and your vision.
06
Built on Relationships
A significant share of our business comes from repeat clients and personal referrals, loyalty earned through decades of trusted craftsmanship.
Local Expertise. Bespoke Craftsmanship.
Home Extensions Southern Highlands: Trusted Local Expertise
KMI Builders is a family-run, Bowral-based building company with more than 30 years of experience delivering home extensions across the Southern Highlands, including Bowral, Mittagong, Moss Vale, Berrima, Burradoo, Exeter and Sutton Forest.
A well-considered home extension lets you stay in the Southern Highlands neighbourhood you chose for a reason, without compromising on the calibre of home you want to live in. At KMI Builders, we craft home extensions throughout the region, and bring the same uncompromising standards to an extension that we bring to a custom home commission.
Led by Kim Middleton and grounded in more than three decades of building experience in this region, we understand what distinguishes a genuinely enduring addition from one that simply adds square metres, an understanding reflected in our Master Builders Association of NSW recognition and the same trusted trades we engage on every project, extension or otherwise.
30
+
Years building across the Southern Highlands
What We Help With
Home Extensions across the Southern Highlands
KMI Builders is a full-service Southern Highlands building company:
01
Home extensions, including single-storey, double-storey and heritage-sensitive additions
02
Custom homes, commissioned and built from the ground up
03
New homes, designed and constructed for individual sites and lifestyles
04
Renovations, modernising interiors while preserving original character
05
Aftersales services, including decks, statue installations and access bridges
A Showcase of Exceptional Craftsmanship
KMI Projects in the Southern Highlands
Renovation | Bowral
Bowral
A cherished Bowral renovation, saw KMI Builders reimagine a beloved cottage's interior, adding two bathrooms and a bright kitchen and living space, all while preserving the character and heart that made it special.
Complete Rebuild | Southern Highlands
A Southern Highlands Country Manor
Built for a family seeking a slower Southern Highlands life, KMI Builders delivered a complete rebuild featuring an expansive kitchen, private parents' retreat and light-filled sunroom, creating a calming family oasis.
Awarded by Industry. Featured Nationally.
A Reputation Built on Recognised Work
Our work has earned recognition that reflects our commitment to exceptional craft:
2019 MBA NSW Excellence in Building Awards, Best Sandstone Work
2019 MBA NSW Excellence in Building Awards, Best Use of Structural Timber
Master Builders Association of NSW member
Painters individually recognised by the Master Painters Association
Featured in Highlife Magazine
Our projects have also been featured in national media, including the Rose Cottage renovation on Amberlane Estate, Bowral, published in Country Style (September 2023) alongside property designer Sarah Parry-Okeden of Wild Orchid Spaces, and a Southern Highlands country manor rebuild published in Home Beautiful (May 2022) with architectural designer Sally Wilkins Studio.
Why Southern Highlands Homeowners Choose KMI Builders
Experience Proven Through Every Detail
KMI Builders is a family-run, Bowral-based company led by Kim Middleton, with more than three decades of building experience across the Southern Highlands. We hold the 2019 MBA NSW Excellence in Building Award for Best Sandstone Work and the 2019 MBA NSW Excellence in Building Award for Best Use of Structural Timber, and our painters are individually recognised by the Master Painters Association.
Our work has been featured in Home Beautiful for a Southern Highlands country manor rebuild with architectural designer Sally Wilkins Studio, and in Country Style for the Rose Cottage renovation on Amberlane Estate, Bowral, with property designer Sarah Parry-Okeden of Wild Orchid Spaces. We are members of the Master Builders Association of NSW and work alongside trusted trade partners including A&R Engineering and Design and Tziallas Omeara Architecture Studio.
Knowledge Built In
Understanding Home Extensions in Southern Highlands
A home extension adds floor area or volume to your existing home without creating a separate dwelling. It can be as focused as a new bedroom at the rear, or as considered as a full first-floor addition with multiple rooms. Homeowners across Bowral, Mittagong and Moss Vale consistently choose to extend rather than relocate, because these established neighbourhoods offer community ties, quality schools and property values that reward thoughtful investment rather than a move elsewhere. A considered extension genuinely lifts a Southern Highlands home's value and liveability when it is executed with the right materials and detailing.
Types of Extensions Available
The right extension type depends on your lot, your family and the character of your existing home. KMI Builders builds each of the following across the Southern Highlands.
- Single-storey rear extensions, creating open-plan kitchen, dining and living zones
- Double-storey additions, which add bedrooms and bathrooms on a new first floor and preserve garden space on smaller blocks
- Side extensions, suited to narrower township blocks in older residential zones of Bowral and Moss Vale
- Outdoor living additions, including roofed verandas and timber decks
Local Planning Considerations
A significant proportion of properties across Wingecarribee Shire, New South Wales, carry heritage or environmental overlays, and KMI Builders has a long history working with these constraints.
Properties in bushfire-prone zones require fire-resistant materials and construction measures compliant with Australian Standard AS 3959-2018. The updated Bush Fire Prone Land Map took effect across Wingecarribee in July 2025, meaning Bushfire Attack Level assessments may require specific requirements for framing, cladding, glazing and ember sealing depending on whether a property falls into BAL-19, BAL-29 or BAL-40.
A Section 10.7 planning certificate identifies the constraints specific to your property, and we recommend obtaining one before committing to detailed design work.
Planning Your Extension Project
Getting the planning right before construction begins prevents costly redesigns mid-build. At our initial consultation, Kim Middleton and the KMI Builders team walk the property with you, discuss your vision and flag any overlay or site issues that will shape the project.
Design and architectural planning sets the direction for everything that follows. Across the Southern Highlands, we work alongside architects and designers who understand the region's architectural language, and north-facing extensions capture winter sun while clerestory windows and skylights prevent deep-plan rooms from becoming dark corridors. Integration with the existing house is where craftsmanship shows: floor level differences of even fifty millimetres between old and new sections require careful transition design.
Council approvals follow a defined path. Wingecarribee Shire Council requires a Development Application for most residential extensions unless the project qualifies as exempt or Complying Development. DA processing in Wingecarribee has averaged 3 - 6 months. Once approved, a Construction Certificate and Principal Certifier must be appointed before our work begins.
Materials and Finishes for Southern Highlands
Material selection in this region balances aesthetics, climate performance, bushfire compliance and long-term value. External cladding options range from fibre cement weatherboard through to natural sandstone or timber weatherboard. Roofing ranges from Colorbond steel, which performs well across BAL ratings, through to slate tiles for heritage projects. Window options range from aluminium frames through to timber-aluminium hybrid windows, which satisfy heritage appearance requirements while meeting bushfire ratings where required.
Next Steps
From Planning to Possibility
A successful home extension in the Southern Highlands requires careful planning, the right approvals, and a builder with genuine local knowledge of heritage overlays, bushfire requirements and climate-appropriate construction.
Contact Kim Middleton and the KMI Builders team for an initial consultation and site visit, where we will assess your property, discuss your vision, and outline the approval pathway for your Southern Highlands home extension.
Frequently Asked Questions
FAQs About Home Extensions in the Southern Highlands
How much does a home extension cost in the Southern Highlands?
Costs depend on extension type, bushfire compliance requirements, heritage detailing, finishing and site conditions. KMI Builders provides a detailed cost breakdown specific to your property and scope at the quoting stage.
How long does council approval take in Wingecarribee Shire?
A Development Application in Wingecarribee has averaged around 3 - 6 months.
Can heritage properties in the Southern Highlands be extended?
Yes, heritage properties can be extended.
Do bushfire zones affect extension design in the Southern Highlands?
Yes, properties in bushfire-prone zones require construction compliant with AS 3959-2018, with Bushfire Attack Level ratings of BAL-19, BAL-29 or BAL-40 dictating framing, cladding, glazing and ember sealing requirements.
Is KMI Builders a licensed builder in the Southern Highlands?
Yes. KMI Builders is a Master Builders Association of NSW member, family-run and based in Bowral, with more than 30 years of experience delivering renovations and custom homes across the region.
