Expert Building Design in Thornleigh

Thornleigh is a vibrant suburb in the Upper North Shore, known for its family-friendly atmosphere, well-connected transport options, and leafy streets. With Thornleigh Marketplace, nearby schools, and easy access to the M1 and Pennant Hills Road, it’s a popular choice for growing families and professionals alike. Homes here range from post-war cottages to modern builds, offering great potential for renovation, extension, or redevelopment.

At DMR Designs, we specialize in drafting services, council approval assistance & building design in Thornleigh—helping you modernize older homes, plan thoughtful extensions, or design a custom new home that meets your vision and Hornsby Shire Council’s regulations.

We proudly service Thornleigh and every suburb across Hornsby Shire, with select availability for projects up to 4 hours from the region.

Why Choose DMR Designs for Building Design in Thornleigh?

  • Tailored for Family Living: We create open-plan designs perfect for modern families and multi-generational households.

  • Smart Upgrades for Older Homes: Ideal for post-war and 60s-era homes needing space, light, and flow.

  • Knockdown Rebuild Experts: Start fresh with a layout made for your block’s shape and slope.

  • Council-Compliant Plans: We manage all tree preservation, setback, and stormwater rules required by Hornsby Shire.

  • Easy, End-to-End Process: We handle the paperwork, consultants, and approvals so you don’t have to.

Our Thornleigh building design projects balance function and comfort while ensuring council compliance from the start.

The Hornsby Shire Council Requirements for Building in Thornleigh

  • General Setbacks:

    • Front: 6–9m | Side: 900mm–1.5m depending on block width and height

  • Floor Space Ratio (FSR):

    • Typically 0.4:1 in R2 Low Density Residential areas

  • Average Block Size:

    • 650–950 sqm, many with existing homes ready for renovation or redevelopment

  • Zoning:

    • Primarily R2 Low Density Residential, with some E4 Environmental Living areas nearby

  • Local Considerations:

    • Properties may have mature trees, stormwater easements, or bushfire overlays, depending on location.

Building in Thornleigh requires careful consideration of zoning overlays, bushfire ratings, and environmental planning policies.

For detailed council regulations and submission guidelines, visit the The Hornsby Shire Council website.

DA vs CDC: What’s Right for Your Thornleigh Project?

We help you determine the most efficient approval path based on your project type and property conditions.

Here’s a quick breakdown to help you understand the difference:

DA (Development Application):

  • Required for projects involving large extensions, tree removal, or site constraints

  • Allows flexibility in design and layout

  • Lodged through Hornsby Shire Council

CDC (Complying Development Certificate):

  • Ideal for straightforward builds or additions on compliant lots

  • Approved by a private certifier when all requirements are met

  • Typically faster if no environmental or heritage issues apply

We’ll evaluate your land, goals, and constraints to determine the best pathway forward.

 

FAQs About Building Design in Thornleigh

  • Yes—we create functional designs that make the most of irregular block shapes and gradients.

  • Very—many homeowners upgrade post-war homes with second-storey additions, new kitchens, and open-plan living.

  • Most projects move from concept to submission in 6–10 weeks, depending on complexity.

  • Not at all—we also work across the entire Hornsby region, including Mount Colah, Hornsby, and Waitara. We're also available for select projects up to 4 hours away from The Hornsby Shire Council area.

  • Cost depends on the scope of your project. We’ll walk you through pricing during your discovery call so you know exactly what to expect.

Ready to take the next step?

We’re here to help you take the next step—whether you’re planning a brand-new build or modernizing a classic home.

Our Building Design Services in Thornleigh

We design custom homes, knockdown rebuilds, duplexes, renovations, and granny flats—tailored to suit Thornleigh’s generous lots and lifestyle.

From practical extensions to complete home transformations, our Thornleigh building design services help your ideas become reality—stress free.

What to Expect: Our Building Design Timeline

A step-by-step look at how we take your project from concept to council approval and beyond.

Every project starts with a discovery call and ends with council-approved, build-ready plans.

Here’s how we make it easy from start to finish:

Step 1 - Discovery Call

  • Let’s chat! We’ll have a quick call to understand your project and see how we can help.

Step 2 -Site Visit & Consultation (5–7 days)

  • We’ll meet at your site (or virtually), take a closer look, and discuss your vision in detail.

Step 3 - Fee Proposal (2 days)

  • You’ll get a clear, no-surprises proposal with the scope, timeline, and costs.

Step 4 - Concept Design (4 weeks)

  • We’ll create initial design ideas and layouts tailored just for you.

Step 5 - Design Development & Expert Coordination (2 weeks)

  • We’ll fine-tune the design and collaborate with any needed specialists (engineer, energy consultant, town planner, geo tech engineer, bushfire, heritage consultant, etc).

Step 6 - Final Adjustments (1 week)

  • We’ll polish everything and prepare the final drawings for submission.

Step 7 - Submission for Approval

  • We handle the council or certifier submission, so you’re ready for the next steps.

Want the full breakdown?

View our detailed process here.

From Plans to Reality: See How It All Comes Together

Explore how we’ve helped Thornleigh homeowners create functional family homes that work with the land and meet all requirements.

Portfolio

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Home Designs

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From value-adding upgrades to brand-new homes, our Thornleigh building design services deliver smart, stylish results—without the stress.

Ready to Start Designing Your New Home in Thornleigh?

We’re here to help you take the next step—whether you’re planning a brand-new build or modernizing a classic home.

We’d love to hear what you have in mind. Book a discovery call or send us a message, and we’ll be in touch within 48 hours.

Not based in Thornleigh?

DMR Designs proudly services the entire Hornsby Shire Council area—from the riverside homes of Brooklyn and Berowra Waters to the leafy streets of Beecroft, Wahroonga, and Westleigh. Wherever you're building across the Shire, we bring the same expert process and personalized design approach to every project.