New London — Contractors are getting a bit more time to prepare bids for the multi-million dollar historic renovation of City Hall.

The city has extended the bid deadline from Dec. 22 to Jan. 19 at the request of contractors who are contemplating the scope of what is expected to be a year-long project.

More than 30 people representing 22 different companies showed up at a tour or “walk through” of City Hall last month, according to Tom Bombria, the city’s community development coordinator and the manager for the restoration project.

“It’s not the biggest job but it is complex with a lot of varied components,” Bombria said.

The city has agreed to borrow $3 million for the project that will involve interior and exterior restorations, Americans with Disabilities Act-compliant entrances and updating of most of the outdated mechanicals — heating and cooling, electrical and plumbing. Bombria said there are small but crucial fixes needed, such as fabricating parts of a marble handrail that were cut during previous renovations.

The design for the renovated City Hall, much of which matches the original components of the century-old building, were prepared by New Canaan-based Architectural Preservation Studio.

City Hall will be completely vacated during the work, which is estimated to take about a year. The 22 offices at City Hall are expected to be relocated to the newly renovated space on the top two floors at the post office building across the street at 27 Masonic St. during the renovations.

The city is still negotiating a lease agreement with postal officials. While the postal service invested in their own renovations, the city is likely to have to pay for some improvements that will include installation of wiring for intranet service.

The city will also have to recreate a city clerk’s office complete with a vault to store records and historic documents — all of which will remain available to the public. Some of the documents date back to the earliest settlements in the city.

City Clerk Jonathan Ayala said even though it is temporary, the new vault must be secure, protected from fire and comply with other requirements as dictated by the Office of the Public Records Administrator of the Connecticut State Library. The state library publishes regulations for things like the construction of town record storage vaults.

The renovated city clerk’s office will be better designed to accommodate the public and employees and also include more vault space, Ayala said.

Some of the city offices, including the probate judge’s office, are expected to remain at the post office building permanently. Mayor Michael Passero has said some offices from City Hall may return to the Stanton building at 111 Union St. — a building vacated in 2015 because of possible structural issues. The building department offices remain in a rented trailer outside the building.

The timeline for the restoration project is still unclear. Bombria said a team of architects and engineers will examine the bids and finalize a recommendation to the City Council.

g.smith@theday.com