M6 Thelwall Viaduct bridge joint replacement scheme
We’re replacing the bridge joints on the iconic Thelwall Viaduct, in Warrington, which carries the M6 motorway over the Manchester Ship Canal and the River Mersey.
Latest updates
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19 August 2026
Scheme starts 1 September
This scheme will begin on 1 September 2026, with initial enabling works taking place beneath the M6 Thelwall Viaduct at Warrington Road.
To work safely, we'll introduce a 24/7 contraflow system on the M6 located around junctions 20 and 21 from 12 October 2026 until winter 2027-28, with traffic running at 40mph.
A contraflow system allows traffic to use the opposite side of the road to maintain same lane capacity so roadworks can be carried out safely while keeping traffic moving.
The first phase of contraflow begins on 12 October which will enable works to be undertaken on the northbound carriageway.
This will involve the following traffic management between junctions 20 and 21 until Spring 2027:
Daytime:
- 4 lanes of traffic will be maintained in both directions of travel, with a 40mph speed restriction in place on both carriageways.
- the southbound carriageway will be utilised for one of the northbound lanes
Night-time:
- 4 lanes of traffic will be maintained on the southbound carriageway, whilst the northbound carriageway will be restricted to one lane between 10pm and 5am.
- the northbound exit slip road at junction 21 will remain open at all times
This approach is the safest way to work while keeping impact on journeys as low as possible and significantly reducing the need for full motorway closures.
Replacing the bridge joints at Thelwall Viaduct will mean some disruption, but it will ensure the safety of road users for decades to come.
To safely set up traffic management layout, the following lane and overnight closures will be needed (all 10pm-5am):
Monday 21 September
Lanes 1 and 2 of the northbound carriageway.
Tuesday 22 and Wednesday 23 September
Lanes 1 and 2 including the exit and entry slip road on the northbound carriageway.
Thursday 24 and Friday 25 September
Lanes 1 and 2 including the exit and entry slip road on the southbound carriageway.
Saturday 26 and Sunday 27 September
Lanes 1 and 2 of the southbound carriageway.
Monday 28 and Tuesday 29 September
Full overnight closure of the northbound carriageway.
Wednesday 30 September and Thursday 1 October
Full overnight closures on the southbound carriageway.
Friday 2 to Saturday 10 October
Lanes 3 and 4 on both carriageways.
Sunday 11 October
Full overnight closure of the northbound carriageway.
During full overnight closures, motorists can follow the route via the M56, M60 and M62 in both directions.
Clear diversion signs will be in place, so we’re advising drivers to plan ahead and allow extra time to complete trips.
Please remember that closures can change at short notice. You can find the latest information on our daily closures page or check for current incidents, disruptions and delays. Our travel alerts give details of high priority incidents on our network.
Project information
Overview
Replacing these joints is essential to:
- reduce the risk of unexpected closures
- keep the bridge working safely and effectively
- minimise disruption for road users over the long term
Milestones
We’ve carefully planned our work at M6 Thelwall Viaduct, which will be carried out in stages:
Stage 1 – September 2026
Northbound contraflow set-up on the M6 motorway, along with scaffolding installation beneath the viaduct.
Stage 2 – Mid October 2026 to March 2027
Bridge joint replacement works on the northbound side of the M6 viaduct.
Stage 3 – Spring 2027
Introduction of the southbound contraflow on the M6 motorway.
Stage 4 – Spring to December 2027
Bridge joint replacement works on the southbound side of the viaduct and removing the contraflow layout.
Stage 5 – Winter 2027-28
Resurfacing, road marking and road studs on both carriageways under overnight lane closures, with traffic sensors replaced under overnight full closures on both carriageways.
Please note, additional traffic management phases may be needed during the scheme.
We’ll update this web page in due course. We always aim to work to the programme, however unforeseen circumstances or adverse weather conditions may mean changes.
Benefits
Replacing these bridge joints is essential to reduce the risk of unexpected closures, keep the bridge working safely and effectively, and minimise disruption for road users over the long term.
Documents
Traffic information
Information about scheduled roadworks and events on our motorways and major roads.Sign up for updates!
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