Skip to main content
Traffic Wales information line 0300 123 1213
The Welsh Government’s traffic information service for motorways and trunk roads in Wales

M4 J32 to J33 Highway Structure Works

M4 Taff Bridge

Essential refurbishment of the M4 and Taff Bridges.

Works will include overnight closures, 24 hour lane closures and a contraflow. 

 An additional phase of works is required in the new year. This is because of adverse weather and the discovery of defects on the bridge. These defects require a greater amount of resource and time to repair. The current contraflow system will still be removed as planned following the overnight closure on December 16th.

Works are due to recommence in January 2022 under lane closures for approximately six weeks. Two lanes in each direction and the slip roads will remain open during daytime works. The contraflow system will not be reinstated. A more detailed programme of works will be provided in due course.

We apologise for the inconvenience and thank the public for their continued patience as we complete these works

Essential bridge deck refurbishment works will be undertaken on the M4 between Junction 32(Coryton) and Junction 33(Capel Llanilltern) on both eastbound and westbound carriageways on Taff River and Taff Rail bridges.


The existing waterproofing was installed over 40 years old. Recent inspections have identified that water is leaking through the bridge joints. 

Failure to do this work now will lead to unplanned future interventions which would be more disruptive than these planned works. 

Traffic will be diverted via the A470, A48 and A4232 during the night time closures.

The works will require a 24/7 contraflow firstly, to be installed  westbound from the 05/11/21 until 30/11/21 between J32 Coryton and J33 (Capel Llanilltern), then eastbound between J33 Capel Llanilltern and J32 Coryton from 01/12/21 – until 16/12/21.

Vehicles over 2.9m wide will be diverted along the A48(M), A48 and A4232 between J32 and J33.

30/11/21 – 16/12/21
Eastbound 2 lane contraflow

Overnight westbound closures from J32 Coryton to J33 Llaniltern (20:00-06:00)

  • 01/12/21-03/21 for 2 nights
  • 09/12/21 for 1 nights
  • 13/12/21 for 1 night.
  • 15/12/21 for 1 night.

Overnight eastbound closures from J33 Capel Llanilltern to J32 Coryton (20:00-06:00)

  • 10/12/21 eastbound off-slip closure for 1 night
  • 11/11/21 from 20:00-06:00 for 1 night
  • 14/11/21 from 20:00-06:00 for 1 night

Overnight closure in both directions from J32 Coryton to J33 Capel Llanilltern (20:00-06:00)

  • 16/12/21 closure for 1 night to remove contraflow system.

For further information, please contact Traffic Wales on 0300 123 1213 or via Twitter @TrafficWalesS


Call the Traffic Wales information line
0300 123 1213
Contact us