Major portions of the State Capitol building, including its rotunda, will close to the public this week as the yearslong restoration project enters its next phase.

Among the projects getting underway are replacement of the roof, and prepping much of the building's interior for new mechanical and electrical systems. That means closing off the rotunda, every floor of the building's East Wing, and the ground and first floors of the West Wing. Department of Administration officials said those spots need to be closed both to protect the public and architectural features.

The $273 million renovation and repair is scheduled to finish up in 2017.

It was initiated with a focus on repairing deteriorating exterior stone, addressing safety concerns in the aging building, replacing outdated systems and creating more public space.

Many of the building's most prominent tenants have already been moved off site. Gov. Mark Dayton and his staff moved to the Veterans Services Building at the south end of the Capitol campus. Attorney General Lori Swanson and her office relocated to office space in downtown St. Paul.

The only tenants remaining for now are state senators with offices in the building.