Walking into Chanhassen Dinner Theatres has always been a time-machine experience. Founder Herb Bloomberg set his best off-kilter architectural instincts to work as he designed and built the sprawling complex in 1968. The lobby looks like a living room with its big stone fireplace and rough-hewn walls full of woodsy aroma.

Quaint as the house that Herb built is, the Chan has aged mightily in nearly 50 years, and Smart Associates has been hired to give the venerable dinner theater a face-lift. Lobbies, box offices, bars and lounges will be updated in the ongoing project, which has already started. Floor surfaces, wall and ceiling finishes and lighting are the keys to the face-lift. No structural changes will take place.

Jim Smart, president of the design firm, said he tried to pull together the theater’s “quaintness, while trying to introduce some of the ‘big theater’ items such as technical lighting.”

Smart said the stone and wood features that give the Chan its ambience will be retained, though the color scheme will change. The theater did not put a price tag on the project but said that most of the work will be completed within a year. The theater last had significant renovations in 1988.

It is not anticipated the work will disrupt the theater’s performance schedule in the main room, the Fireside stage and the downstairs Playhouse. “Sister Act” is running in the 625-seat main theater.

A group led by artistic director Michael Brindisi, choreographer Tamara Kangas Erickson and producer Steven Peters bought the theater business in 2010 from the family of Thomas K. Scallen. Three years later the group was able to buy the 90,000-square-foot building from the Bloomberg family.

The complex — among the oldest and largest dinner theaters that still survive in the United States — includes three theaters, several banquet rooms, two bars and rehearsal space.