The large white building at 160 Church Street, right across from the Castro Safeway, is best known as the former home of Blockbuster Video, which closed in 2011 after years in the space. For four years, it's hosted Spirit Halloween pop-ups during the fall, but sat vacant for the rest of the year.

That changed late last year, when Flagship CrossFit announced it would be permanently moving into the long-empty space. Originally set to open in March of this year, the gym (which also has a location in the Financial District) got tied up in the permitting process, pushing its opening back significantly. Now, it finally has an opening date: January 11th, 2016. 

"We're really excited to be opening after the long delays," operations manager Ryan Schaper told us. "A lot of work has been done, and we're in the final stages of coating our hardwood walls, completing restrooms and changing areas, and installing the equipment."

Flagship's rig, described as "monkey bars for grown-ups."

Schaper describes Flagship CrossFit's classes as "recess for adults," and there's plenty of equipment to play on. Large metal rigs line the northern wall, providing space for pull-ups, muscle-ups, and weighted squats. Kettlebells, medicine balls, dumbbells, and barbells provide plenty of options to throw, lift, and slam in a variety of functional workouts. There are plyo boxes for plyometric exercises, too.

Upstairs, there's a sunny, east-facing room that could host yoga, spin, or cardio classes, depending on what members want. "The space, overall, will be constantly evolving based on the needs of our customers," Schaper said.

The upstairs multi-use room, which boasts a view.

"We began as a CrossFit gym about two years ago, and have since evolved a bit into functional fitness," said Schaper, who got his start in finance and joined Flagship after discovering a passion for CrossFit. "Because this type of exercise involves overcoming challenges and obstacles as a group, we're really building on the social element of it all."

To build camaraderie, Flagship has created spaces for hanging out around the gym. The "athlete lounge," currently planned for the front of the gym, will cater to groups hanging out before and after their classes, while an outdoor patio area will host barbecues and other social functions.

"Classes become groups of friends as they conquer challenges together, and many enjoy spending time together outside of their workout," Schaper said.

Like most exercise studios, Flagship tries to offer a class for every skill level. "For newcomers, our fundamentals class allows you to jump in and get a good workout right away, while learning proper form and movement for more advanced classes," Schaper told us. "Our Core Performance class is our primary class, which requires existing knowledge from the Fundamentals or any previous CrossFit experience. It's an hour of cardio, lifting, and balance work." 

For those who want more cardio and less weight, Flagship also offers a Fit class that emphasizes mobility and range-of-motion. People with injuries are welcome in all of the classes; Schaper said that Flagship's instructors are all trained both in accommodating workouts around an injury and helping with injury prevention. Each class constantly mixes up its routine, to challenge different muscle groups and keep things fresh. 

Flagship posts new workouts for each day on its website and app, so people can see what lies ahead and sign up for an upcoming class. The new gym will start with seven classes per day, growing based on the needs of members.

"Our other location currently has about 20 classes, starting early in the morning and running into the evening," Schaper said. Some instructors will come from the FiDi location (250 Montgomery St.), and others will be added over time.

While Flagship will officially open for classes on the 11th, the plan is to host a more formal opening event down the line. "The two-year anniversary of the opening of the first location is at the end of January, so we'll most likely have a combined event for both at the new gym on Church," Schaper said.

To learn more about classes, instructors, and prices, visit Flagship's website.