About Leithal Designs
Luxury Commercial Design.
Delivered With Depth, Precision, and Purpose.
Great commercial spaces aren’t created by chance — they are created through experience, structure, and an uncompromising commitment to detail. Leithal Designs exists for business leaders who expect their workplace, clinic, hospitality venue, or retail environment to reflect the calibre of their brand.
With a values-driven process, two decades of complex project experience, and deep local knowledge across South-East Queensland, we design and deliver luxury commercial spaces that perform as beautifully as they look.
Our philosophy is simple: your space should elevate your business, not introduce risk.
Our Story - Born From a Belief That Luxury Commercial Design Should Be Intelligent, Personal, and Risk-Free
Leithal Designs was founded by Sonia Leith, a multidisciplinary designer with more than 24 years of experience across complex commercial, government, medical, retail, hospitality, and premium residential projects.
Her background in Building Design, Interior Design, and Commercial Architectural documentation gives her a unique vantage point — one that blends creativity with technical mastery.
Across two decades, Sonia witnessed a recurring problem in the design industry:
commercial clients were expected to make high-value decisions with unclear information, inconsistent advice, and no structured roadmap.
Projects went over budget. Timelines blew out. Quality slipped. Not because clients lacked vision — but because the process lacked clarity. Leithal Designs was created to change that.
Every project is guided by a structured, values-based methodology that Sonia refined across medical clinics, four-level office fitouts, government facilities, distilleries, retail stores, and multi-site refurbishments. Her QBCC Commercial Building Designer licence, medium-rise qualification pathway, and hands-on project management experience offer clients peace of mind in an industry where risk is high and precision matters.
Today, Leithal Designs is recognised across Brisbane, the Gold Coast, and SEQ as a trusted authority in luxury commercial interior design, blending creativity, compliance, and construction knowledge into spaces that endure.
8th November
What does our values-based approach look like?
We are Creative
You’ll never see your design show up in another build or fit-out.
We are Collaborative
Our clients are at the centre of everything we do.
We have High Standards
Every detail of your project is accounted for and is of the highest standard.
We are Resourceful
We thrive on coming up with innovative solutions to the natural challenges that arise in a build project.
Our Mission
Our Vision
Our Values
High Standards as a Non-Negotiable
Luxury isn’t an aesthetic — it is a standard of thinking. Our clients expect materials that last, workmanship that holds up under pressure, and detailing that enhances brand presence. We honour that with a meticulous approach to documentation, design intent, and technical delivery.
Clarity Over Assumption
Every project begins with discovery, analysis, and feasibility. Assumptions derail projects — clarity protects them. Our structured design roadmap ensures informed decisions at every stage.
Design with Integrity
We design for longevity, not trend cycles. Timeless materials, climate-appropriate selections, and sustainable solutions form the backbone of our approach.
Collaboration & Communication
We believe high-end results come from respectful relationships, transparent conversations, and a disciplined process that supports everyone involved — clients, consultants, builders, and end users.
Our Expertise
Built for the Complexity of Commercial Design
Sectors We Specialise In
- Workplace & Office Fitouts
From boutique firms to multi-level corporate headquarters. - Medical, Dental & Wellness Clinics
Workflow optimisation, acoustic treatments, infection control, accessibility, and regulatory compliance. - Retail Environments
High-end, brand-driven spaces engineered for customer flow and durability. - Hospitality & Leisure
Breweries, cafés, restaurants, and experiential venues that blend performance, atmosphere, and emotion. - Government & Institutional Projects
Built-form upgrades, accessibility improvements, and compliant design across SEQ and beyond.
Each project benefits from Sonia’s extensive experience in both architectural and interior design, paired with her ability to coordinate consultants, manage tenders, and work alongside builders to ensure design integrity throughout the build.
Meet Sonia
Principal and Director of Leithal Designs
SONIA T. LEITH DIRECTOR Lic:QBCC | Dip.I.D&D | Dip.B.D&Tech
Sonia Leith is the Director and Principal Designer at Leithal Designs.
With extensive know-how on the build process and project delivery, Sonia is renowned fordelivering authentic, creative, and functional spaces and buildings that are tailored to each project’s unique needs.
Over two decades, Sonia has developed a conscientious and intentional design process thatunderpins the Studio’s values-based approach and has gained Leithal Designs a reputation for the highest standards, reliability, and trustworthiness.
Sonia has widespread knowledge in dealing with both small- and large-scale complex projectsfrom bespoke residential renovations, commercial boutique retail fit outs to developments and applies the same meticulous methodology to each project.
“I love seeing our client’s vision come to life.”
Best Design Health
Services Over $500K
Leithal Designs was engaged to deliver a highly resolved, wellness-driven interior for Proud Smile Dental Clinic – located in the bustling Hope Island Marketplace. The brief was clear: deliver a space that transcends traditional dental environments by crafting a warm, inviting, and elegant setting that prioritises both patient experience and operational excellence.
Our Values-Based Methodology
A Proven, Risk-Mitigating Process Trusted by Clients Across South-East Queensland
Commercial clients value certainty — around timeframes, costs, quality, and compliance. Our structured design process is engineered to safeguard your investment from start to finish.
1. Discovery & Diagnostic
We begin by asking the right questions — about your operations, brand, users, constraints, and objectives. This stage eliminates guesswork and identifies what success truly looks like.
2. Research & Feasibility
We assess site conditions, compliance requirements, opportunities, and risk factors. Understanding constraints upfront prevents costly rework later in the project.
3. Concept & Design Development
Ideas take shape, supported by 3D modelling, spatial flow planning, and material selections tailored to your brand identity and operational needs.
4. Technical Documentation
This is where details become reality. Our construction drawings and schedules are highly resolved to ensure builder accuracy, cost clarity, and seamless procurement.
5. Tender Management & Builder Coordination
We manage a structured tender process with trusted builders — ensuring competitive pricing, quality control, and alignment with the design intent.
6. Guidance Through the Build
Throughout construction, we remain involved to review work, maintain design accuracy, and support problem-solving so your project stays on track.
This process does more than deliver high-end design — it reduces risk, protects your budget, and ensures your space is built to the standard your brand deserves.
Local Expertise, Elevated for Luxury Commercial Clients
Designing for SEQ is not the same as designing for other regions. Climate, lifestyle, regulations, and building performance expectations differ — and so do the needs of high-end projects.
Our deep local knowledge allows us to:
- select materials that perform in SEQ’s humidity and heat
- anticipate council and compliance requirements
- collaborate with the region’s most trusted builders and consultants
- integrate sustainability practices that improve operational efficiency
For luxury commercial clients seeking longevity, cost-efficiency, and environmental responsibility, this local insight is a strategic advantage.
Sustainability as a Marker of Modern Luxury
Today’s premium commercial clients expect spaces that support wellbeing, reduce energy consumption, and stand the test of time.
We incorporate:
- Low-energy lighting and compliant electrical layouts
- Durable, timeless, low-waste materials
- Biophilic principles that improve mood and performance
- Climate-appropriate finishes and construction detailing
The result? Spaces that feel refined today — and still look exceptional years from now.
Our Team
Our Impact
Design That Moves Businesses Forward
Our work has shaped commercial environments for:
- Infinity Group Australia
- Hearing Australia
- The Estate Lawyers
- Harcourts
- Target Physio
- Crafty Monk Brewery
- Multiple government agencies
- Premium private developers and entrepreneurs
Clients consistently praise our clarity, communication, detail-driven process, and ability to turn complex constraints into elegant, functional solutions. (“Highly detailed”, “pure good taste”, “managed to perfection”, “a refined, professional office that reflects the calibre of our firm”.)
These are not just design outcomes — they are business outcomes.
Why Clients Choose Leithal Designs
- Founder-led expertise on every project
- QBCC-licensed commercial building designer
- Structured, risk-mitigating design process
- Exceptional detail resolution & documentation
- Strong commercial understanding (budgets, workflows, operations)
- Local SEQ insights that improve buildability and longevity
- High-end materiality & refined spatial outcomes
- Proactive communication from start to finish
Frequently Asked Questions
What types of projects do you specialise in?
Leithal Designs focuses on luxury commercial interior design projects across:
- Corporate offices and workplaces
- Hospitality and leisure venues
- Retail environments and experiential spaces
- Medical, dental and allied health clinics
We also support selected premium residential and mixed-use developments where architectural complexity and design quality are central to the brief.
What project size do you typically take on?
Our portfolio ranges from compact but high-impact tenancies (around 70–125 m², such as boutique clinics and cafés) through to multi-level, multi-thousand square metre workplaces and service centres.
If you are unsure whether your project is the right size, we are happy to review scope and advise on the best way forward during an initial discussion.
Do you only work in Brisbane and the Gold Coast?
We are based in South East Queensland and undertake the majority of our work across Brisbane, the Gold Coast and surrounding regions.
For high-end commercial projects, we may also support clients across other parts of Australia, subject to scope and feasibility.
Do you handle both design and project management?
Our primary role is architectural and interior design, including:
- Concept design and design development
- 3D modelling and visualisation
- Documentation and coordination
- Tender administration with builders
We stay involved during construction as a design advocate, helping to answer design-related queries, review key details and maintain alignment between approved design and built outcome.
How early should we engage Leithal Designs?
The earlier, the better. Ideally, you engage us during:
- Site selection or lease negotiation, or
- Early planning for a refurbishment or relocation.
This allows us to provide early feasibility insights, highlight constraints, and advise on space requirements before commitments are locked in.
Do you advise on budgets and cost estimates?
We do not replace a quantity surveyor or builder, but we provide early guidance on realistic cost ranges using tools like our Building Cost Estimator and past project benchmarks.
During tender administration, we help compare builder submissions and assess value based on both cost and quality.
How do we start a project with you?
Typical first steps:
- Enquiry: Complete the form on our Contact page or phone our studio.
- Discovery Call: A focused discussion to understand your project, timing, and objectives.
- Proposal: A tailored fee proposal outlining scope, stages, and deliverables.
- Engagement: Once accepted, we schedule a formal briefing session and begin the design process.
You are welcome to reference favourite projects from this page during our first conversation.
Let’s Create a Space That Moves Your Business Forward
Every successful project begins with a conversation. Whether you’re planning a new commercial space or refining an existing one, we would love to guide you through the next step.
Your space has potential. We help you realise it — brilliantly, intelligently, and with absolute care.