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Tony Andrews founded Tandem in 1997, and is the Director of Construction at Tandem. He manages the site superintendents, project managers, and estimators. He enjoys site and field work, value engineering, operations management and lean processes, as well as business development. Having been in the industry for 27 years, his favorite part is being able to solve problems and seeing the confidence clients have, knowing they’ve made the right decision in choosing Tandem. Tony was born and raised in the Chicagoland area, and now lives in Park Ridge with his family.

Dimitri Nassis received his bachelor’s in Psychology and Philosophy from the University of Illinois at Chicago and a Construction Technician Certificate from Triton College. After graduating, he spent a decade in the financial industry as an options trader at the Chicago Board of Trade and the Chicago Board Options Exchange. He left the trading floor and followed his lifelong calling by entering the world of construction and real estate development. After reconnecting with childhood friend Tony Andrews, he helped found Tandem in 1997 and began Tandem’s journey as a developer. In addition to real estate, Dimitri also helps guide the company’s marketing and property management teams. Most recently, Dimitri was instrumental in helping secure Tandem’s largest and most noteworthy development and construction project, MODE 2501, which is a $23M, 78-unit mixed-use building in Logan Square, completed in early 2017.

Chris Walsh received a Bachelor’s Degree in Architecture from the University of Illinois at Chicago and is a licensed Architect in Illinois, Wisconsin, Indiana, Michigan, and Colorado. Prior to becoming a partner at Tandem, he worked for one of the nation’s largest architecture firms and then became the Vice President of Architecture for a national home builder. Additionally, Chris has a background in construction, having worked in the field throughout high school and college. Chris manages the architecture team and serves as the Principal Architect at Tandem.

Sean Staunton received a Bachelor in Public Service from Northern Illinois University. Prior to joining Tandem, he worked with Lettuce Entertain You, Brinker International, and was a realtor at Coldwell Banker. His role at Tandem includes project management, client relations, and business development. He is also the warranty service and OSHA systems manager. His expertise is in designer interior build-outs, including new construction, remodeling, and landscape/exterior space construction. Sean is the Director of Special Projects and Service, helping serve clients and building associations beyond the completion of their projects.

Jeffrey Hreben received his Bachelor’s in International Studies with an emphasis in Economics from the University of Chicago. He earned a Master’s in City Planning from the University of Pennsylvania and a certificate of Real Estate Development from the Wharton School of Business. Prior to joining Tandem, he worked at Progressive Housing Ventures, a residential construction and development firm in Philadelphia that capitalizes on transit-oriented development opportunities. His work at Tandem focuses on various real estate development initiatives, including zoning and entitlements, financial underwriting, investor relations, and project management.

Justin joins Tandem as our Development Manager and will be working with the Tandem Development team.  Most recently Justin was with Stage Equity Partners in acquisitions and asset management. While there he was involved in vetting new medical office opportunities and assisting in all manners of transaction work.  Before that he was at Dayton Street Partners and Lakeshore Management where he honed his skills in underwriting, market research, development, and operations after completing his BA and Master’s in Accounting at Indiana University. Justin brings a wealth of experience that will be a great complement to our work here at Tandem. Outside of work he’s an avid IU basketball fan and be sure to ask him to tell you about his love of travel or what how he’s hitting the golf ball.

Pat grew up in southern Indiana and graduated from Purdue University with a B.S. in Construction Engineering and a minor in Management.  After working on a variety of complex projects for a large general contractor in Los Angeles, he moved to Chicago and now lives with his wife and two kids in Elmhurst.  He joined Tandem in 2015, is a LEED Accredited Professional and is OSHA 30 certified.  Pat led the field operations for the recently completed Avenir tower and is overseeing the construction of the new 20 story Avra building.  His expertise in scheduling, site logistics, LEAN Construction principles and team communication greatly contribute to the success of his projects.

Kevin was born and raised in Green Bay, Wisconsin and moved to Chicago after attending college in Cleveland, Ohio. He has a Bachelor of Science in Civil Engineering from Case Western Reserve University as well as a Master of Science in Civil Engineering from Illinois Institute of Technology. He is a licensed Structural Engineer in Illinois, New York, and Arizona and has been involved with the design and construction of over 2,000 apartments, condos, and student housing units, along with healthcare, cultural, higher education, and sports facilities. He currently acts as Project Executive to manage all aspects of new construction and renovation projects. His expertise is in budgeting, scheduling, construction logistics, value engineering, and coordination of building systems. His favorite part of his job is developing innovative construction solutions through collaboration with design professionals and subcontract trades.

Mike hails from the South suburbs of Chicago, and has lived in Chicagoland for most of his life. He studied Construction Management at Bradley University and currently acts as a Construction Manager at Tandem, dealing with the day-to-day supervision of the construction jobsite. He makes sure that quality is being controlled so that clients are receiving the best product possible. His favorite part of the job is that every day is different; there are always new challenges that require thinking outside of the box. The end product also gives him a sense of pride, as he has contributed to the ever-changing cityscape. Mike loves spending time with his kids and playing a round or two of golf in his free time.

Kimm Donnelly brings over two decades of exceptional leadership and operational expertise in multi-family property management. She joined Tandem Property Management in 2022, following a 21-year tenure at Draper and Kramer, where she built a diverse and dynamic portfolio spanning affordable housing, senior and student living, market-rate properties, retail, and third-party management.

Kimm’s extensive experience includes managing high-value capital improvement projects, as well as leading complex acquisitions and dispositions. Her greatest strength lies in her ability to build, motivate, and empower teams—driving performance, exceeding goals, and fostering a culture of excellence.

She is a proud graduate of Southern Illinois University with a BS in Business Administration and holds an Illinois Real Estate Managing Broker License. Deeply committed to professional development and industry leadership, Kimm has been a long-standing member of IREM, where she served as the 2014–2015 Regional Vice President overseeing five Midwest chapters and was the 2009 Chapter President.

Outside of work, Kimm stays active and grounded through outdoor adventures—whether it’s running, hiking, or biking—with her two daughters and their spirited puppy by her side.

Kaitlyn has been with Tandem since 2018.  With a strong background in strategic problem-solving and extensive expertise in Yardi software, she has played a key role in the successful launch of three high-rise residential buildings in the Chicago market.  Kaitlyn has also led the implementation of new software solutions to enhance the experience of both residents and property managers.  A graduate of Ohio State University, Kaitlyn is passionate about streamlining building operations to improve efficiency and tenant satisfaction. Outside of work, she dedicates her time to fundraising for clean water initiatives with Team World Vision, running marathons, and spending time with her nieces and nephew.

Caroline has been a dedicated professional in the multifamily industry since 2012, holding a Certified Apartment Manager (CAM) designation from the National Apartment Association (NAA) and an Accredited Residential Manager (ARM) credential from the Institute of Real Estate Management (IREM). With a strong background in property management, she specializes in overseeing both residential and commercial properties, focusing on operational efficiency, resident satisfaction, and asset value growth. Recognized for her exceptional communication and problem-solving skills, Caroline fosters strong relationships with property owners, residents, and vendors to ensure a seamless management experience. Outside of work, Caroline enjoys spending quality time with her family and exploring new shopping and dining in the City.

Born and raised in Lithuania, I’m a passionate Residential Real Estate professional with 17 years of experience in property management, sales, and marketing. I love what I do — helping properties thrive while building vibrant communities. I’m fluent in three languages, which has been a tremendous asset in connecting with diverse clients and teams.  With an ARM (Accredited Residential Manager) certification and a Bachelor of Science in Marketing and Management from Colorado Technical University, I’ve developed a knack for solving challenges, driving revenue growth, and leading successful teams.  As the Property Manager for Avra and Sage, I focus on creating exceptional living experiences, optimizing operations, and ensuring financial performance. My journey has also included roles as Leasing Director at TJBC and Property Manager at Greystar, where I honed my skills in strategic negotiation, budgeting, and community relations.  Whether it’s navigating landlord-tenant laws, mentoring teams, or launching innovative marketing campaigns, I’m always excited to make a positive impact.

Born and raised on the Northwest side of Chicago (“Go Cubs Go!”), Ryne attended Chicago State University obtaining his a major in Recreation Management and a minor in Physical Education. He previously worked as a Concierge at an apartment building in the Streeterville neighborhood. Ryne describes being a Concierge with Tandem as being a “first responder,” as well as security, a source of communication to residents, potential residents, team members, couriers, vendors, and beyond. His favorite parts of the job are the Tandem team, the residents, and the building (Avenir).

Manuel Hernandez was born and raised in Chicago IL.  He has joined Tandem this May of 2021 as the Assistant Building Engineer at Mode Logan Square. Before Tandem Manuel has worked at Steiner Industries as the production manager, safety coordinator and fire safety captain. This industry is growing and he is excited to contribute and share his knowledge, experience and energy to provide a safe, clean and well-organized building that exceeds our tenants’ expectations and draw focus to the Mode vision. When he is no working at Mode he loves running & cycling not just recreationally, but as sport. He can proudly say that he has completed two marathons, several half marathons and Century (100 mile) rides.