With existing buildings at full occupancy, Crow Holdings has begun work on an 110,000-square-foot addition to Old Parkland, its exclusive office campus off the Dallas North Tollway at Oak Lawn and Maple avenues. Three new buildings will be developed on the west side of the project.

Construction has already begun on an underground parking garage; next up is development of two of the planned buildings. Parkland Hall will total about 50,000 square feet; Commonwealth Hall will total about 30,000 square feet. A third, to-be-named office building will also total about 30,000 square feet and will be built after the first two fill up.

Construction is expected to take about 18 months. Beck Architecture is designer on the project. The general contractor for the parking component is Brasfield & Gorrie. The construction contract for the office buildings has not yet been awarded.

Brasfield & Gorrie also is building TRT Holdings’ new headquarters within the park at 4001 Maple Ave. The 164,000-square-foot facility was designed by HKS Inc., in keeping with Old Parkland’s Jeffersonian architectural style. TRT Holdings, the parent company of Omni Hotels & Resorts and Gold’s Gym International, will relocate employees from the company’s existing facility in Irving when the new building is completed late next summer.

At full build-out, Old Parkland will total about 450,000 square feet. The picturesque, heavily-treed campus is arguably the most exclusive office address in North Texas, securing rents in the low to mid-$40s per square foot.

Crow Holdings renovated two of the historic Parkland Hospital facilities and moved its headquarters to the campus in 2008. It later added two more office buildings, Woodlawn Hall and Reagan Place, bringing the existing total to about 176,000 square feet.

“We’re trying to build extremely high-quality, authentic, classical buildings,” said Harlan Crow, chairman and CEO of Crow Holdings. “We want it to feel like a small college campus, and we want it to celebrate American tradition.”

The Old Parkland campus is managed by CNL Commercial Real Estate.