Galliford Try has been appointed to deliver two office contracts in Northamptonshire and Surrey, worth a combined £77m.
It will build a new £38m headquarters for Northamptonshire County Council in Northampton.
The 17,600 sq m four-storey building will regenerate an area on the south side of Northampton town centre and consolidate the council’s existing offices in the town into one building.
Galliford Try will also build a café and carry out hard landscaping on the site.
The project will be finalised in December 2016.
In a second deal, the contractor will build an office building for offshore engineering company Subsea 7 at Sutton in Surrey.
The £39m project will deliver a 13,935 sq m Category A office space on the site of a former car park. Construction will begin in 2014 and will be finalised in late summer 2016.
Galliford Try executive chairman Greg Fitzgerald said: “We are delighted that Northamptonshire County Council and Subsea 7 have entrusted us with such significant projects.
“We have a strong reputation in the office sector and we look forward to providing these two clients with the first-class facilities they require.”
Galliford Try is delivering the £28m Category A office space in St James Square, London (pictured).
The company announced on Tuesday that Mr Fitzgerald would assume the role of executive chairman up until December 2015 after chairman Ian Coull stepped down from the board.