Bucks motorists using the M40 warned about impact of £23m year-long works
Motorists in Bucks who use the M40 could face overnight and full road closures during a £23 million refurbishment of Loudwater Viaduct, with work due to finish in autumn 2027.
The bridge carries the M40 over the Loudwater Valley in High Wycombe. National Highways said work began in February 2026 and described the programme as maintenance and defect work.
A spokesman said: “We are renewing our roads to keep them fit for the future and are carrying out a programme of maintenance and defect works to Loudwater viaduct to ensure the M40 stays safe and reliable.”
He added that the work was typical for a bridge of its age.
VolkerLaser was appointed by UK Highways M40 Ltd to carry out the refurbishment.
The company says overnight carriageway closures will be needed for some bearing replacement work, while lane and full road closures will be used to replace joints across the bridge’s 24 spans. No closure dates were given by National Highways or VolkerLaser.
The work includes concrete repairs across eight spans and bearing replacement on four spans. Those sections will be jacked up to allow the bearings to be changed.
The programme also includes installing a cathodic protection system and repainting steelwork. A cathodic protection system uses a controlled electrical current to help slow corrosion of the steel reinforcement inside the concrete.
In an update, VolkerLaser said the jacking system was in operation and concrete repairs and protective coating work were under way. The company described the refurbishment as a £23m project. In an earlier update, it said the project was scheduled to finish in October 2027.
National Highways said work began in February. VolkerLaser said site mobilisation began in March, with contracted works starting in mid-April.
Built in 1968 as part of the second stage of the High Wycombe bypass, the viaduct carries the M40 over the Loudwater Valley. Its twin three-lane decks are supported by reinforced-concrete piers and crosshead beams.
The viaduct has undergone major repairs before. In evidence to Parliament in 2009, John Laing said earlier M40 maintenance work had uncovered failing reinforcement in the viaduct’s parapets, leading to about £4m of rectification work.
The Government had estimated the main works to build the viaduct at £1.9m in 1967, with completion expected the following year.
The M40 was built in stages: its first section, between Handy Cross and Stokenchurch, opened in 1967; the route to Oxford was completed in 1974; and its extension to the M42 near Birmingham opened in 1991. It provides an alternative motorway link between London and the Midlands.