The work is worth £15.5 million and has been awarded as part of the Northumberland County Council framework agreement.
The framework was won by GB Building Solutions in January this year, after successfully completing £40 million worth of projects, on or ahead of programme and within budget, under a previous three year agreement.
The current framework will last for five years with an additional three year option, and is expected to be worth up to £200 million over its term.
The work is for Malvins Close, New Delaval and Newsham Primary Schools as part of a cluster of work in Blyth.
Additional refurbishment work will also be carried out at Horton Grange Primary, Croftway Primary and Blyth Community College.
GB Building Solutions will also begin alterations to two existing school buildings in Cramlington as part of the previous framework; this work will eventually accommodate four schools onto two sites.
Chairman and chief executive of GB Building Solutions Martin Smout said: “It is a testimony to the strength and depth of GB Building Solutions that we are able to carry out several projects in the same region starting more or less simultaneously.”