Design Mechanical signs 10-year lease at Thornton industrial park

DENVER — Design Mechanical Inc. has signed a 10-year lease for 129,140 square feet at Creekside Innovation Park, a two-building industrial development in Thornton, according to developer OCC Industrial.

The lease covers the entire Building 1 and will commence upon delivery of the facility in the second quarter of 2027. Construction is scheduled to start in June.

Design Mechanical, a mechanical systems contractor backed by Comfort Systems USA, will serve as the project’s anchor tenant. The lease was finalized before construction began.

“Securing Design Mechanical as our anchor tenant before a single shovel hits the ground is exactly the kind of validation that defines a well-positioned project,” said James Carolan, chief investment officer of OCC Industrial.

The 252,200-square-foot development will consist of two industrial buildings at the southwest corner of 148th Avenue and Washington Street in Thornton. Building 2, totaling 123,060 square feet, remains available for lease or sale and can be divided into spaces starting at 20,000 square feet.

The project will include 32-foot clear heights, 130-foot truck courts, ESFR sprinkler systems and 4,000 amps of power in each building.

Tyler Smith, Alec Rhodes and Aaron Valdez of Cushman & Wakefield represented OCC Industrial in the transaction. Anya Marmuscak, Chris Schultz and James McGill of JLL represented Design Mechanical.

According to OCC Industrial, the property is located within an Enterprise Zone and is not subject to metro district assessments, resulting in mill levies about 40% lower than competing projects along the North I-25 corridor.

“Thornton is where we want to be for the long term, and Creekside gave us the confidence to commit,” said Bob Frese, president of Design Mechanical. “The location puts our team at the center of the region’s growth, with access to the I-25 corridor, labor pool and infrastructure.”

Comfort Systems USA reported more than $9 billion in revenue in 2025 and a backlog of approximately $12 billion, according to the company.