Road users from the A24 and the A27 will be controlled by temporary traffic lights and signed diversions next week as engineers conduct repairs to a deteriorating bridge near Upper Beeding.
Engineers noticed parts of Court Bridge along the A283, near Upper Beeding, were leaking water, according to West Sussex County Council.
West Sussex Highways is set to begin work to fix the deteriorating bridge, which crosses River Adur north of the old cement works, on Monday, June 19.
The road on top is also due to be resurfaced.
The work is due to take five days to complete between 6.30am and 7pm.
It will then continue over two consecutive weekends, from 8pm on Friday, June 23 to 6am on Monday, June 26 and 8pm on Friday, June 30 to 6am on Monday, July 3.
During the first week, traffic will be controlled by temporary traffic lights, manually controlled at peak times.
Over both weekends the bridge will be closed.
A fully signed diversion route will be set up via the A27 and A24 for road users to follow.
West Sussex County Council’s Cabinet Member for Infrastructure and Highways Bob Lanzer said: “This is important maintenance work we carry out regularly on our bridges to keep them safe for road users.
“Work of this nature does require a road closure over the weekend, so we ask motorists to follow the signed diversion routes.
“There is likely to be disruption, so please allow extra time for your journeys if you are travelling this route.”
The scheme costs £120,000, according to West Sussex County Council.