Northamptonshire County Council has begun the hunt for a contractor to build its new offices, codenamed Project Angel.
The contract, estimated at £37.6m, requires the construction of a new civic office building in the centre of Northampton at the council's Angel Street site.
The current design contract will be novated to the successful bidder, who will have overall responsibility for the delivery of design and build phases of the project.
The timetable calls for invitations to tender being issued in May and a contractor being appointed in September. Construction should start in January 2015 and complete by November 2016.
The county council has calculated the consolidating 2,000 staff from 12 buildings into one would eventually save £54m in future running costs over the next 30 years.