Wates Living Space and Mulalley have been awarded contracts to refurbish 4,000 homes for Stevenage Borough Council.
The deal is worth £45m over five years and covers 550 blocks of flats across the borough.
Refurbishment works will cover roofs, windows, structural repairs, electrics and paving, along with some redecoration.
Wates is also planning to provide extra community benefits as part of its works.
Wates Living Space managing director David Morgan said: “Our team is looking forward to starting work on behalf of the council later this year, and we are currently preparing a community investment programme that will ensure our presence brings lasting benefit to businesses and individuals across Stevenage.”
Stevenage Borough Council has a £1bn 30-year investment plan for its social housing stock.
It plans to spend £448m on new homes and £660m on maintaining and improving existing properties.
The council has already invested £64m over the past seven years on internal works to council homes.
Councillor Jeanette Thomas said: “This is a major programme that will prolong the life of these homes, and ensure good-quality housing for local people.”
Stevenage Borough Council is also investing £350m in regenerating its town centre.
Mace has been named development partner on the scheme and is currently working on a planning application that is expected to be submitted later this year.