Our STORY
Built on trust. Proven through delivery.
Appian Civil is a Toowoomba-based civil construction company specialising in subdivision and land development projects across the Toowoomba region and broader South East Queensland.
Founded by Clayton MacDonald and Will Siebenhausen, the business began in 2021 under the name Connected Civil, delivering residential and commercial civil projects throughout the Toowoomba region.
As the company grew in scale, capability and ambition, it rebranded to Appian Civil, reflecting a stronger, more established civil construction business with the experience, systems and resources to deliver complex projects with confidence.
Today, Appian Civil combines the technical capability of a major contractor with the direct accountability of a hands-on local partner. Clients work directly with the people leading the business, allowing decisions to be made quickly, communication to stay clear and every project to receive the attention it deserves.
Appian Civil is not built on volume. It is built on quality, reliability, trust and a genuine commitment to delivering civil works that stand up on site, on paper and over time.
45+ years
combined leadership experience
$50M+
completed projects
1,000+
residential lots delivered
$56M+
live project portfolio
The values behind every project.
Every project is approached with the client’s priorities in mind.
With Clayton and Will actively involved, communication is direct, decisions are made quickly and issues can be resolved without unnecessary layers.
Quality
High standards on every project, regardless of size.
From materials and workmanship through to inspections and approvals, Appian Civil holds a high bar across every stage of delivery.
Reliability
We mean what we say and follow through.
Appian Civil maintains a consistent site presence, keeps clients informed and backs up project commitments with practical action.
Client Focus
Every project is approached with the client’s priorities in mind.
With Clayton and Will actively involved, communication is direct, decisions are made quickly and issues can be resolved without unnecessary layers.
Trust
Strong projects are built on honest relationships.
Appian Civil keeps clients informed on variations, budget movements, subcontractor coordination and site progress, with no runarounds and no surprises.
Our Team
Meet the people behind Appian Civil.
Appian Civil is led by an experienced team with deep capability across civil construction, project management, construction management, business operations and HSEQ.
The business is director-led, with practical experience guiding both site delivery and client communication. This hands-on leadership model means the people making decisions are close to the work, close to the client and accountable for the outcome.
Clayton MacDonald
Director & Project Manager
Clayton brings 30 years of civil construction experience to Appian Civil, including 20 years in project management roles. His experience spans residential, commercial, subdivision and industrial civil works across South East Queensland.
With a strong understanding of both technical project requirements and practical site delivery, Clayton plays a key role in planning, managing and delivering projects to a high standard.
Will Siebenhausen
Director & Construction Manager
Will brings 20 years of civil construction experience, spanning hands-on plant operation through to the management of major subdivisions, commercial projects and TMR road upgrades.
On site, Will provides the practical knowledge, guidance and problem-solving required to keep complex civil projects moving. His experience is central to the way Appian Civil supports its team and delivers for clients.
Justin Scutt
General Manager
Justin brings more than 30 years of experience across construction, electrical and civil infrastructure. His background includes strategic leadership, business growth, operational management and financial performance.
At Appian Civil, Justin oversees business operations, strategic direction and organisational performance, helping support sustainable growth, strong client relationships and continuous improvement across the business.
Greg Dalziell
HSEQ Manager
Greg is an experienced senior leader with more than 20 years’ involvement across the construction, energy and civil infrastructure sectors.
As HSEQ Manager, Greg supports Appian Civil’s approach to quality, safety and environmental performance. He holds a Diploma of Work Health and Safety and a Diploma of Business, combining formal qualifications with extensive industry experience.
Supporting the communities we help build.
As a Toowoomba-based business, Appian Civil understands the importance of contributing to the communities where its people live, work and deliver projects.
Beyond the work delivered on site, Appian Civil supports local and community-focused organisations including Hope for Our Children, Stationery Aid and Toowoomba West Special School.
This commitment reflects the way Appian Civil approaches its role in the region, not only as a civil construction company, but as a local business invested in long-term community outcomes.