National Highways, formerly Highways England, will carry out the work in the central reservation between Oatens Bank Bridge at Horsley and Hassock Bog Bridge at Heddon-on-the-Wall from Sunday, 19 September.
The work aims to improve safety and reduce severe injury in the event of road accidents.
Michael Morgan, project manager for National Highways, said: “This work is vital to ensure the continued safety of road users.
"It will be carried out in the daytime, generally between 9am and 4pm to avoid peak hours, with an earlier finish at 1pm on Fridays when traffic flows start to increase. We advise people to allow extra time for their journeys.”
Both carriageways will be reduced to one lane and a 50mph speed restriction will be put in place.
The maintenance is due to be completed by Sunday, October 24, but this is weather dependent.