Our Leadership

We are constantly listening, learning and adapting. That defines what we do.
It is our commitment to sustainability, that defines who we are.
Together, our vision is to create transformative environments, having fun in the process.

Joanne McCallum

Executive Director & Principal

B.A., M.E.Des.(Arch), OAA, AANB, FRAIC, LEED AP

Joanne McCallum is the Co-Founder and Executive Director of mcCallumSather. From the firm's inception, she’s instilled a commitment to environmentally conscious practices, positioning it as an industry leader in sustainable design. read more

Michelle Austin

Managing Principal, Operations

MAATO, OBEC, LEED AP

Michelle Austin has been with mcCallumSather since its inception in 1996, with over three decades of experience providing oversight in quality control, quality assurance, field review and sustainable design. read more

Drew Hauser

Director, Design & Business Development

HONS. VIS. ARTS., B.ARCH., OAA, AANB, NSAA, AIA (NY), FRAIC, CAHP

Drew Hauser provides design and business development leadership, impact that extends to mcCallumSather’s internal teams as well as its clients, partners and peers. His influence has been pivotal in award-winning design solutions that set precedents or are the first of their kind, challenging conventional notions while aligning with clients' financial goals. read more

Matt Bolen

Managing Principal

BAS, M.ARCH, OAA, MRAIC, CPHD

Matt’s area of expertise is multi-res building design ranging from mid-rise supportive housing to high-rise market rate.  His professional interests include mass timber, modular/ prefabrication, and high-performance design. read more

Michael Trussell

Managing Principal

BAS, M.ARCH, OAA

Michael Trussell is an award-winning designer and a skilled leader, able to develop efficient solutions and exciting outcomes on behalf of his clients, including a mix of institutional, commercial, industrial, and healthcare facilities. read more

Heather Gordon

Managing Principal, Finance & Administration

CPA., MAcc.

Heather Gordon is the Managing Principal of Finance & Administration with mcCallumSather, having helped oversee the team’s substantial and sustainable growth over the past decade. read more

Kevin Van Hartingsveldt

Principal, Project Manager

Dipl.T.(Arch.), LEED AP, PMP

Kevin Van Hartingsveldt, Principal with mcCallumSather, has an exceptional attention to detail and profound technical understanding, which contributes to the success of a diverse range of projects. read more

Liam Brown

Principal, Architect

M.Arch, OAA, AANB, MRAIC, PMP

Liam Brown is a Principal with mcCallumSather. His systematic approach to work, coupled with a unique blend of creativity and practicality, has earned him the appreciation of clients across various sectors including his specialty in Science & Research design. read more

Willems Ransom

Principal, Architect

B.F.A., M. ARCH., NCARB, AIA

Willems Ransom, Principal, is an award-winning designer and leader within mcCallumSather. Willems is known for crafting unique spaces, each meticulously tailored to their unique context. read more

William Neal

Principal, Architect

B.Arch (Hons.), Dip.ArchTech, OAA, AANB, MRAIC, PMP, LEED Green Associate

William Neal, Principal at mcCallumSather, leverages over a decade of architectural experience, hands-on construction background and complementary technical degree to spearhead some of the firm’s most innovative projects. read more

Ashraf Azeem

Senior Associate, Architect Design Lead

B. Arch., OAA, PMP

As a Senior Associate and Design Lead at mcCallumSather, Ashraf Azeem is a seasoned mentor, teacher, and designer. read more

Laura Sears

Senior Associate, Marketing Lead

B.J. (Hons), MBA

Laura Sears, Senior Associate and Marketing Lead, leverages over two decades of experience  in journalism and professional services marketing to drive growth for mcCallumSather. read more

Mary Georgious

Senior Associate, Mechanical Lead

P.ENG, LEED AP BD+C, CHES

In her role as the mechanical engineering lead and Senior Associate, Mary Georgious is an accomplished leader with a unique blend of experience and specializations that adds value to her clients. read more

Adam McCaughan

Associate, Architect

M.ARCH., OAA, LEED AP BD+C

As a Project Manager, LEED Facilitation Lead, who often fills the role of Authorities Liaison, Adam McCaughan showcases a breadth of experience that speaks to his deep understanding of processes within the architectural realm. read more

Brian Torrens

Associate, Architect

BAS, M.ARCH, OAA

read more

David Riley

Associate, Mechanical Engineer

P. Eng., PMP, LEED AP BD+C

David Riley, Associate with mcCallumSather, has carved a niche for himself as a versatile designer who excels in projects that pose unique challenges, employing data-driven approaches to shape meaningful design solutions. read more

Kenneth Roy

Associate, Technologist

Kenneth Roy is a detail-oriented Architectural Technologist with over 10 years experience in the industry. He has extensive experience in a variety of building sectors that range from multi-unit residential, transitional housing, office buildings, industrial and health care facilities. read more

Liz Gabaldo

Associate, Interior Design Lead

B.I.D. (Hons)

In her career spanning over 35 years, Liz Gabaldo, Associate with mcCallumSather, has earned widespread recognition for her exceptional talent in crafting beautiful interiors that distinctly capture the unique identities of her clients. read more

Mark Koppeser

Associate, Contract Administrator

CET, OACETT

read more

Morgan Wright

Associate Architect

BAS, M.ARCH

read more

Greg Sather

Retired

B.Arch., OAA, MRAIC, LEED AP

Co-founder and Director, Greg is responsible for design direction, sustainable design initiatives and providing technical excellence oversight for the firm’s projects. His experience with the design of high performing spaces has resulted in ground breaking projects and firmly established his reputation as a leader in sustainable design. read more