WATERVILLE — The owners of the Hathaway Creative Center have announced that construction has begun on finish work for office space for MaineGeneral Health at 10 Water St. The additional 35,000 square feet of Class A office space will increase the total space occupied by MaineGeneral at the complex to more than 75,000 square feet and more than 330 jobs.

Tom Niemann, a member of the partnership that has redeveloped the historic mill building, said in a news release, “We are very pleased to play a role with MaineGeneral and the City of Waterville in sustaining quality employment in the area and in returning new life to this spectacular structure. We can now see our original vision coming to fruition.”

“As the largest employer in Waterville, MaineGeneral is committed to the economic development of downtown Waterville,” said Chuck Hayes, CEO of MaineGeneral Health. “We are pleased to continue to make another significant contribution to Waterville’s downtown revitalization and to be a part of the preservation of this historic landmark.”

The five-story structure includes residential apartments on the top two floors, which have been fully occupied for more than four years. MaineGeneral and four other office tenants occupy the second and third floors. The first floor includes space for offices and retail, as well a cafe that recently opened.

Paul Boghossian, a partner in the project, said in the release, “We are very pleased to be using Peachey Construction, a local contractor, to undertake this project along with other local subcontractors. This is all about generating local jobs as well as restoring an historic building.”

The owners said they feel positive about their ability to finish leasing the remaining office and retail space now that a large concentration of workers and residents are located at the site. When the additional MaineGeneral space is occupied in August, more than 600 people will be living and working at the complex.

Boghossian said, “This is the top-quality commercial space in the region, with great access, great views and great finish work in addition to the historic feel of the large, open, common areas inside the building.”

Baldacci Real Estate Group handled the real estate brokerage for the transaction.