BATH, Maine — The owner of the former Bath hospital will be before the planning board on Tuesday seeking another developmental subdivision and site plan approval for additional apartments in the mixed use space.

The approvals are needed to make sure those 12 residential units won’t tax the city’s existing infrastructure — sanitary, traffic and stormwater. The change of use would decrease those impacts.

The planning board could vote on granting the approvals Tuesday at the meeting which starts at 6 p.m. at City Hall in council chambers.

Bob Smith of Kennebec Landing, LLC is owner of what was renamed the Midcoast Center for Higher Education at 9 Park St. He decided to construct apartments in the former hospital building after he began losing commercial tenants after purchasing the property from the city in 2013 for $799,000.

Andrew Deci, Bath’s planning director, said Smith needs the approvals to convert non-residential space to residential space and add units in an existing building. He was before the city’s planning board in July 2014 and was granted approvals to construct 15 apartments. Up to 30 are allowed under existing zoning.

Smith said Thursday the Navy has rented out those 15 apartments. Ten are currently filled and another three will be filled next month. The commute to Bath Iron Works is only 1.2 miles, Smith said, “so these guys can go home and have lunch.”

Now that Mid Coast Medical Group has moved into a new building on Central Avenue, Smith plans to build the additional 12 apartments in that space. He was unsure Thursday as to whether this will be leased to the Navy or not, noting he’s received calls from people who have been tenants in the past at other buildings he’s owned who have asked to be on the list if he has apartments available in this building.

With the construction of these additional units, there will be little space left in the building, Smith said. There is room where Volunteers of America was formerly located as well as on the top floor of the three-floor building. He has a letter of intent pending with a large contractor that deals with BIW. If it lands a contract its competing for, the company will be in one of the commercial spaces.

Smith has leased space out to four artists, he said. The former caterer occupying the cafe space left but Run With Soup, which makes and delivers soup, will move into the cafe space on Oct. 1.

A gym is also available to tenants and anyone working in the building.

Smith was initially very concerned with the exodus of businesses and educational institutions from the MCHE shortly after he bought it. The conversion of some of the space to residential has helped occupy former empty rooms. He’s worked every day there for the last seven months and it has paid off, he said. There is now enough revenue to pay the bills.