Client
National Highways
Value
£2.5M
Sectors & Services
Highway Structures Concrete Repair Coatings Corrosion Control ECI (Early Contractor Involvement) Projects Projects
The M6 Junction 4A to M42 interchange is a critical component of the West Midlands motorway network, providing essential connectivity between the M6, M42, and routes serving the North West, South East, and Birmingham Airport. Handling over 150,000 vehicles daily, this section of the network is vital for regional and national traffic, freight movement, and access to major transport hubs.
CRL, on behalf of National Highways, delivered a maintenance programme on the bridge linking these motorways to safeguard its structural integrity and reduce the need for future interventions. The project combined specialist engineering expertise with robust planning to ensure the bridge continued to meet operational and safety requirements while minimising disruption to one of the UK’s busiest corridors.
Services Undertaken
- Removal of existing paint coatings and surface oxidation from structural steelwork
- Mechanical preparation of steel to SA 2.5 standard
- Application of a five-coat protective system, including corrosion-inhibiting primer, two-pack epoxy intermediate coat, and aliphatic polyurethane topcoat
- Vacuum blasting for controlled removal of old coatings and minimisation of dust and debris
- Night-time traffic management to reduce disruption on a high-volume motorway
- Early stakeholder coordination, including Road Space Booking and traffic management teams
- Ecological survey and environmental compliance, including bat checks
- Project management and site coordination, ensuring efficient delivery and supply chain oversight
- Planning for parallel ECI-led concrete repairs on the structure
for Every Job
The maintenance works focused on the structural steel elements of the bridge, covering approximately 3,000 m². All existing paint coatings and surface oxidation were removed using vacuum blasting, a technique that allowed controlled containment, minimised dust and debris, and maintained compliance with environmental regulations. Following this, steel surfaces were prepared to SA 2.5 standard, ensuring a clean, bright metal surface suitable for high-performance coatings. A five-coat protective system was then applied, beginning with a corrosion-inhibiting primer, followed by a two-pack epoxy intermediate coat, and finished with a durable aliphatic polyurethane topcoat. These treatments collectively provide robust long-term corrosion protection, even in a high-traffic, exposed environment.
Due to the bridge’s location above one of the UK’s busiest motorway sections and near the HS2 corridor, all works were scheduled at night to minimise disruption. Early coordination with stakeholders, including Road Space Booking and traffic management teams, ensured smooth operations. An ecological survey was conducted prior to works to ensure compliance with environmental regulations, including bat checks. The project was led by CRL’s Technical Manager, Chris Hinton, with site coordination by Dan Foxhall and James Lewis, ensuring strict environmental compliance, efficient supply chain management, and safe delivery under challenging operational conditions. Parallel ECI-led concrete repairs on the structure are scheduled for the following year.
"Working on such a critical stretch of the UK’s motorway network has been both a challenge and a privilege. From coordinating with multiple stakeholders to ensuring zero environmental impact, the team has delivered with precision and care. Using vacuum blasting and a robust five-coat protection system, we’re safeguarding the structure for decades to come. It’s a great example of how CRL brings together technical excellence, sustainability, and teamwork to keep the country moving."
Chris Hinton | Techincal Manager | CRL
The five-coat protective system ensures long-term durability of the steel bridge elements, providing enhanced corrosion resistance and reducing the frequency of future maintenance interventions. Surface preparation to SA 2.5 standard maximised coating adhesion, while vacuum blasting minimised environmental impact and maintained structural cleanliness.
The use of a corrosion-inhibiting primer and high-performance epoxy and polyurethane coatings ensures resilience in a high-traffic, exposed environment. By integrating rigorous environmental and traffic management controls, the project safeguarded both the bridge and the surrounding motorway network.
These measures collectively support asset management objectives, extend the structure’s service life, and provide sustainable protection for one of the UK’s most strategically important transport links.
the repair
