The Johnson County Board of Supervisors chose to go local on a project with a muddled history.

The supervisors approved a contract with Neumann Monson PC for all services related to the courthouse annex design plans in a unanimous vote on Thursday. The firm, in association with Venture Architects, was hired to complete a study, analyzing options for a courthouse annex to be built adjacent to the existing courthouse.

“We chose specifically to use a local firm,” Supervisor Rod Sullivan said. “That was part of what went into our decision-making.”

The Iowa City firm is tasked with designing the proposed annex and has been providing estimates for the supervisors recently.

The courthouse annex will only be built if a referendum passes by a super majority — or 60 percent — of the voters in November. Kim McDonald, the architect in charge of the project, said a referendum would be held if the supervisors vote to proceed after the firm follows up with an additional presentation and resolves any concerns.

Bond referendums have failed to pass twice, but if the referendum were to pass, development would follow quickly.

“Assuming everything goes smoothly, construction of the annex could start as soon as July 2015,” McDonald said.

Sullivan said the benefit of going through a local firm, like Neumann Monson, is that the architects are more invested in the project.

Neumann Monson, 221 E College St., was founded as a four-person, firm in 1977. Since then, it has expanded to Des Moines and Sioux City.

The current plan for the courthouse annex is to add up to six courtrooms in a building to the south of the courthouse. Officials have said the existing courthouse and jail are overcrowded and are riddled with security problems.

The current estimate for the courthouse annex is $30.8 million. The price was recently raised as the design plans have changed. The update includes a larger building with conference rooms, more public space and storage, and a connection between the two buildings. As a result, the cost per square foot rose.

Supervisor Janelle Rettig said the supervisors have faced criticisms for the aesthetics of the last proposal designed by Neumann Monson, but the supervisors are trying to change those details on the upcoming proposal in order to please voters.

“I’m hearing a lot of people complain to get a new architect,” Rettig said. “But they’ve spent more than three times the effort on this project than we’ve paid them for.”