Client: Swansea City Council
Contractor: Knights Brown
Location type: Coastal defence scheme – sea wall
Completion: August 2025

The challenge

This £26 million coastal protection project was designed to reduce the risk of flooding and coastal erosion for residents and businesses along this popular stretch of Swansea Bay. The existing sea defences – comprising a 0.5km vertical concrete sea wall and a 0.7km sloping revetment – had deteriorated over time, leaving the area increasingly vulnerable to flooding.

Alongside strengthening the coastal defences, the scheme aimed to enhance the promenade as a popular leisure destination. Improvements included decorative surfacing, landscaping, lighting, seating, litter bins and improved connections to Mumbles Road. Key works involved raising the central section of the promenade by approximately half a metre, reinforcing the sea wall and revetment, replacing railings with a low pedestrian wall, widening the promenade to create a shared pedestrian and cycle route, and introducing new hard and soft landscaping.

The project also presented several logistical and environmental challenges. Limited road access for HGVs required carefully coordinated material deliveries to minimise disruption to local residents, businesses and road users. Construction activities also needed to be managed sensitively to protect a neighbouring Site of Special Scientific Interest (SSSI), an important habitat for both local and migratory bird species.

Tarmac's solution

Tarmac became involved at an early stage as the project's key materials supply partner, providing aggregates, concrete and decorative asphalt to support both the structural and aesthetic requirements of the scheme.

The concrete supplied for the sea walls, slipways and stairways was required to deliver high strength, excellent abrasion resistance and rapid early strength development to meet the contractor's construction programme. The design also incorporated detailed textures and patterns cast into both the sea wall and the new pedestrian wall.

A specialist C40/50 micro-silica concrete mix was developed for the sea wall. As the concrete was placed on a steep gradient, achieving the correct slump was critical. If the mix was too dry it could not be properly placed and finished, while an overly wet mix would flow down the structure. The concrete also needed to remain workable during the typical 45-minute journey to site while setting quickly enough to withstand the incoming tide.

As supply continued over a two-year period, the concrete mix was refined seasonally to maintain consistent performance throughout the project.

Results and benefits

Completed on time and within budget during summer 2025, the project showcased close collaboration between Tarmac, the contractor and the wider project team.

From July 2023 onwards, Tarmac supplied approximately 16,500m³ of concrete, including 10,500m³ of specialist high-strength micro-silica concrete, together with 660 tonnes of ULTICOLOUR coloured asphalt for the promenade.

Careful planning and coordination across Tarmac's concrete and asphalt operations ensured materials were delivered efficiently despite the site's logistical constraints.

The completed sea defences now provide improved protection against coastal flooding for 126 properties, including homes and more than 50 local businesses. The regenerated promenade has also enhanced the area's appearance and accessibility, creating an attractive public space that is expected to further support Swansea's tourism economy, already worth around £660 million annually. The successful outcome reflects the collaborative approach adopted by all project partners throughout the scheme.