One of downtown Dallas' most unique office projects is creating a new use for an old building.

The almost 80-year-old Masonic Temple on Harwood Street served thousands of Masons in North Texas for decades.

For almost 10 years, the property has been vacant awaiting redevelopment.

Now, the 41,000-square-foot historic building is being renovated as part of the East Quarter development on downtown's east side.

The three-story former fraternal organization building was purchased this year by Dallas developer Todd Interests and its partner JPMorgan Asset Management.

"We are busy cleaning up the inside and removing asbestos and other materials," said Todd Interests' Patrick Todd.

The developer is installing new elevators and adding a roof deck for prospective office tenants.

"We've had a lot of interest from single-tenant office users," Todd said. "It's about the size of two floors of a downtown office building.

"A company can have their own office building, front yard and parking lot all to themselves."

They are calling it the Block House.

When the Masonic Temple was built in 1941, it housed 6,000 Masons and 750 members of the Eastern Star.

1 / 2The interior of the building originally housed five lodge rooms.(DMN files) 2 / 2 The exterior of the Masonic Temple on Harwood Street in downtown Dallas.(LOUIS DeLUCA / 102770)

The building cost $350,000 and was constructed in art deco style of stone, metal and glass.

Inside, there was a 500-seat auditorium, five lodge rooms, a banquet hall, library, lecture rooms and offices.

The exterior is 24-inch-thick Texas limestone — not veneer.

The building was designed by the Dallas architect Flint & Broad, which worked on the aquarium at Fair Park and parts of the original Love Field passenger terminal.

"The ceiling heights increase as you go up," Todd said. "The top floor is 33 feet of clear height.

"We've got a 6,000-square-foot room with no columns," he said. "There are not a lot of buildings like that."

This summer, Todd Interests and J.P. Morgan Asset Management acquired more than a dozen buildings and land on the east side of downtown. They have begun renovations of the old commercial properties, most of them built between the 1920s and 1930s.

The old buildings are being converted to new office, restaurant and retail uses, and the entire neighborhood has been rebranded East Quarter.

Tech and creative companies are being pitched office space in the project.