The Mayo Clinic said Monday that it will add five floors to St. Marys Hospital and reno­vate other parts of the campus in Rochester, part of a $72 million project.

The floors will be added to the Mary Brigh East Building, and the third floor of the Domitilla Building will be renovated. Both projects will begin in the second quarter of 2014 and are expected to be completed by early 2016.

Construction on the first four floors of the Mary Brigh Building is currently wrapping up, part of a surgery expansion project to create a new post-anesthesia care unit. Three floors of the five-floor addition will be patient-care units, each with 23 private rooms. The remaining two floors will be built out and reserved for future expansion and mechanical infrastructure.

The expansion will provide patients with private rooms. Ceiling lifts will be installed for patient and staff safety, and patients will have private bathrooms and showers. Each room will offer space for family members to stay overnight and include additional workspace for staff.

The new expansion will create an additional 131,800 square feet of finished space and 25,300 square feet for future expansion. Once completed, Mary Brigh East will be nine floors.

The project will replace 73 inpatient beds currently located in the Joseph Building, which was built in 1922 and has become outdated, Mayo said. Once the renovation is completed, the Joseph Building will be used for hospital-based staff support space.

The third-floor renovation of the Domitilla Building, which currently houses one of the largest adult general care inpatient units at Mayo Clinic, involves modernizing the unit by providing private patient rooms with bathrooms and showers and adding ceiling lifts.

“Hospitals are the location where care is delivered to the most complex and seriously ill patients,” said Dr. Amy Williams, Mayo’s medical director of hospital operations.

“We pursued this expansion to meet the patients’ needs, ensure a safe environment and to improve the patients’ overall hospital experience,” Williams said. “The new areas are designed to continue to provide high-quality care to our patients for many years to come.”