The bridge over the River Wye at Builth Wells will be closed to motorists at night for nearly three weeks next month.
Traffic Wales has confirmed the A483 bridge will be shut between 7pm and 7am from Monday, March 3, until Friday, March 21.
A diversion will be in place via Beulah and Newbridge-on-Wye, starting at Number 4 Broad Street in Builth and from the roundabout by the Royal Welsh Showground in Llanelwedd, where the A470 and A483 meet.
The closure is to allow “essential carriageway surfacing works and footway improvements” to take place.
Traffic Wales has confirmed that the pedestrian footway will remain open, but people should wait at the closure points until they can be safely escorted or directed through.