The city of Saint John is trying to stop the decline of some of the historic buildings, including the jellybean houses, it bought for potential use in the new Peel Plaza police station development.

The jellybean houses, so called because they are painted bright colours, are Second Empire row houses with distinctive carved windows along Wellington Row. They were built around 1860 and are in a state of disrepair.

Peel Plaza project manager Bill Edwards said Thursday that the jellybean houses were vacant when bought by the city and several walls were black with mould. Much of the plaster had to be removed to keep the mould from spreading, he added.

"We removed all the carpeting that was here, was full of mould," Edwards said. "We replaced the roof because we believe this is where the water came in and then entered the rest of the building. So, we removed all that and put in a new roof."

The building has no power, heat or water, Edwards said, but it is stable and will be monitored.

"We will do regular inspections to make sure things aren't deteriorating or that there aren't persons living in here.

"But the reason we did that is to stabilize the buildings, and that's why we took out the walls and the ceilings to make sure that the mould didn't continue. We're satisfied that the building is in stable condition and is not in any jeopardy at this point."

A few doors down the street, contractors are installing one of four new electric furnaces in a cavernous former synagogue, which is also now city property.

Heat is required for the building, project engineer Gerry Matson said.

"It is set at about 15 degrees [Celsius] right now, just to get the building up to temperature. We'll monitor it on a regular basis and lower the temperature as required and keep it at just above freezing," Matson said.

Saint John has no plans to become a landlord. Both the former synagogue and the jellybean buildings are being held in case developers of the Peel Plaza complex and parking garage want to include them in a larger project.

Peel Plaza will be the city's new justice complex, comprising law courts built by New Brunswick's Department of Justice and a three-storey police facility built by the Saint John Police Force.