Uptown Dallas' first mixed-use development — the half-century-old Quadrangle — is headed for redevelopment.

Stream Realty Partners, which bought the property in January, intends to construct a 12-story office building and new retail space at the Quadrangle.

"Fifty years ago, the Quadrangle was a destination-oriented boutique retail center tucked back in a little neighborhood," said Stream Realty managing director Ramsey March. "It was innovative for its time and set a high standard in its day.

"Our job now is to envision what it can be for Uptown in the 2020s."

It will be a major makeover for the 4-acre project on Routh Street between McKinney Avenue and Cedar Springs Road.

Built in 1966 as a Southwestern style compound of one-of-a-kind shops and small offices, the Quadrangle has gone through several transformations. A redevelopment in the 1980s added an office building.

The Quadrangle Shopping Center in Dallas' Uptown district is getting new retail and office construction.. (Shaban Athuman / Staff Photographer)

Stream Realty plans to build a 335,000-square-foot office tower at the north end of the Quadrangle site. The building will replace a section of existing retail space on Howell Street.

The existing eight-story office building, Theater Three and the retail buildings on the Laclede Street side of the project will remain in place.

Dallas architect Omniplan designed the new office building with a metal and glass exterior. All of the parking will be in an underground garage. The surface lots that now serve the complex will be replaced with new construction and wide, landscaped walkways.

"The property is ringed by surface parking, and if you are a pedestrian, it kills your urban experience," March said. "Our vision for Quadrangle in its new form will feature architecture, open space and retailers that all meet the challenge of the new urban experience."

One of the biggest changes is planned for the corner of Routh and Howell, where the existing retail building will be replaced with a collection of small freestanding eateries and shops.

"We call it a modern retail bungalow concept," March said. "They are meant to be walkable and desirable to the workers and the residents in the neighborhood."

He described the planned office building, which also has retail on the lower level, as "modern industrial design."

The mostly glass exterior has windows framed with Corten steel. Plans call for a rooftop terrace with views of the neighborhood and nearby downtown Dallas.

"The Quadrangle sits right in the geographic heart of Uptown," March said. "We see a surge in interest in Dallas from creative users and tech companies from all over the country that desire a location in Uptown.

"We think the Quadrangle can be the epicenter in Uptown for those tech and creative tenants."

Stream Realty hopes to start construction in the middle of next year and have the project ready for tenants by 2022.

The developer will seek zoning changes to increase the height of the building, which would still be considerably lower than nearby Uptown towers.