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Steve Heymes

MEP Specialist

Headshot of Danielle Sessler

Danielle Sessler

Senior Project Manager

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Joe Walker

Project Executive

Joaquin Aburto

General Foreman

Professional portrait of GLY employee Dennis Sizemore.

Dennis Sizemore

Cement Mason Superintendent

Jackson Reid

Project Engineer

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Cassie Withrow

Executive Administrator+Administrative Services Manager

Tyler Tonkin

President+CEO

Trevor Lunde

Director of Virtual Design+Construction

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2026 GLY Construction, Inc.

Headshot of Danielle Sessler

Danielle Sessler

Senior Project Manager

Associate DBIA™

Construction was always part of the plan for Northwest native Danielle, having grown up in a family that owned a contracting business. She took a few detours first, earning a BFA in Metalsmithing and Art History from Central Washington University and working as a Senior Estimator focused on honing her preconstruction services skills. When she landed at GLY in 2013, we quickly recognized her background would be perfect for Design-Build projects. Outside of work, Danielle enjoys hiking, bouldering, climbing—and collecting “odd things that most people scratch their heads over.”

Headshot of Joe Walker

Joe Walker

Project Executive

Joe is a self-motivated, engaging and results-driven construction professional with over 30 years of planning, scheduling, value engineering, and estimating experience on high profile and complex construction projects. His years and variety of experience in the industry makes him a valuable member of the GLY team. He can tackle whatever scope of work is required. His work experience throughout the United States [OR, CA, NV, FL, MD, NJ, NY…to name a few] has taught him there’s no place like home. Joe has four children with his wife—and high school sweetheart—and loves to go hunting and fishing whenever he can.

Joaquin Aburto

General Foreman

Joaquin approaches each day on the jobsite with a people-first attitude, emphasizing the importance of a collaborative team culture in finding efficient solutions and creating a learning environment for everyone. One of his favorite aspects of construction is that he leaves each workday having learned something new from his teammates. When he’s not out in the field, you can find Joaquin adventuring in the PNW with his 5 kids.

Professional portrait of GLY employee Dennis Sizemore.

Dennis Sizemore

Cement Mason Superintendent

Dennis is the go-to guy on anything and everything concrete. At age 15, he poured and finished driveways, patios, and shop slabs. When he started at GLY at 18, he was the youngest journeyman in his union. Today, he's a concrete master who oversees projects up to one million square feet. His favorite aspect of the job is the constant change of scenery since he's not on one single project for an extensive amount of time. While concrete is a big part of Dennis’s life, he makes plenty of room for his kids, fishing, hiking, and visiting Kauai, his happy place.

Jackson Reid

Project Engineer

Headshot of Cassie Withrow

Cassie Withrow

Executive Administrator+Administrative Services Manager

Excellent customer service comes naturally to Cassie, who approaches every task with a can-do attitude. As Executive Administrator, she enjoys working with people that encourage her and test her limits but allow her to have fun along the way. She manages her time—and many others’—with extraordinary ease and keeps things running like a well-oiled machine. Outside the office, you’ll find Cassie hiking, exploring the city, and when the sun comes out, boating on Lake Washington—all with her husband and pups by her side.

Tyler Tonkin

President+CEO

Since joining GLY in 1998, Tyler has played a pivotal role in shaping the company’s culture and project delivery excellence. Now serving as President and CEO, he brings a collaborative spirit, deep technical expertise, and a strategic mindset to every facet of the business. Tyler’s leadership has guided some of GLY’s most complex and transformative projects—from integrated hospital expansions to urban highrise developments. His commitment to client advocacy and team empowerment continues to inspire innovation and elevate performance across the organization.

Trevor Lunde

Director of Virtual Design+Construction

Associate DBIA™

Trevor is an industry innovator with over 22 years of experience devoted to creating synergy between architectural design and technical construction. Trevor leads strategic business planning for the company’s Virtual Design and Construction [VDC] and technology efforts and provides companywide training on GLY delivery philosophy and VDC process. Having been both a project architect and a construction manager, he identifies valuable opportunities for coordination and collaboration amongst designers, engineers, and tradespeople. Trevor respects each discipline’s individual process and expertise while ensuring constructability. Trevor’s downtime is spent playing with his kids or fishing.