The executive management team at DivisionOne has extensive experience in all phases of construction while managing the day-to-day operations and maintaining a family-like atmosphere. All major decisions are made as a team, and clients know that everyone on this team can be easily reached at any time.

Todd Hamby

President, Partner

Todd is a founding partner of DivisionOne and is responsible for the project operations of the company. He ensures all our projects are completed safely, on-time, and meet the clients’ expectations.


  • Master’s in Business Administration – 2000
    The University of Texas, Pan American, Edinburg, TX
  • Bachelor of Business Administration – 1994
    Sam Houston State University, Huntsville, TX


  • LEED® AP

20 years of experience

Todd Callaway

CFO, Partner

Todd is a founding partner of DivisionOne and is responsible for all financial and accounting matters. He is also responsible for risk management, human resources, office operations, and business development.


  • Bachelor of Business Administration in Accounting – 1993
    University of Texas at Austin


  • Licensed CPA / LEED® AP


  • CPA, Public and Industrial Accounting Roles
  • 10 years as Manager at Deloitte & Touche

25 years of experience

Zac Koletar

Vice President of Estimating

Zac began at DivisionOne as an Estimator in June 2012 and has progressed to become the Vice President of Estimating. Zac has learned and mastered the skill of estimating projects from design through job startup, including detailed budgets at every phase of design, value engineering, and competitive bid. Zac applies his expertise to create successful relationships with owners, architects, engineers, and subcontractors, and helps deliver projects within budget that bring the owner’s vision to reality.


  • Bachelor of Science in Construction Science
    Texas A&M University


  • Estimator and Project Manager at Gamma Construction

15+ years of experience

Bruce Casares

Vice President of Operations

Bruce began his construction career in 1977.  He has held several positions including superintendent, project engineer, estimator, project manager and safety director. As Vice President of Operations for DivisionOne, Bruce provides expertise and oversight to all our projects under construction, helps determine appropriate staffing & project teams, and coordinates project management, and field supervision.


  • Dyad Construction and Gamma Construction

40+ years of experience