DESIGN experts who formed part of the project team behind the £4.6 million upgrade of the Largs sea wall have shed more light on the technical know-how behind the work.

Lanarkshire-based FP McCann were the specialist pre-cast design team involved in the North Ayrshire Council (NAC) project, which was completed at the end of May, working with principal designer RPS Group and main contractor RJ McLeod.

NAC originally gave its backing to the scheme back in March 2021, when it was given a price tag of £3 million, amid mounting concern that the original wall, which was built in the 1970s, was no longer fit for purpose after decades of exposure to sea water.

FP McCann, which has its Scottish headquarters in Uddingston, worked with RPS Group on the installation of the new wall, which is designed with a curved top to reflect waves back towards the water.

It’s the same height as the existing promenade wall, and is between one and four metres high along its 300-metre length between the RNLI slipway and Aubery Crescent.

The promenade itself has been widened following infill works between the existing and new walls.

The first stage of building work involved a “significant” beach excavation, along with piling to allow for the installation of a concrete foundation, which is itself designed to prevent erosion around the base of the structure.

Complex structure: Seawall in Largs being built purpose built for years to comeComplex structure: Seawall in Largs being built purpose built for years to come (Image: FP McCann)

Before the work on the permanent wall began, a temporary ‘tide protection’ wall, consisting of pre-cast Lego-style blocks, had to be put in place for the safety of the workers.

FP McCann manufactured ‘marine grade’ precast concrete units for the permanent wall, featuring a corrosion-inhibiting ‘admixture’ – chemicals used to improve the properties of an existing concrete mix – as well as an abrasion-resisting ‘aggregate’, to strengthen the mix and, it's hoped, to give the new structure a much longer life than the one it's replacing.

The company made and delivered a total of 138 individual units for the wall at its Uddingston site, the smallest weighing three tonnes and the largest 22.5, for installation by the RJ McLeod contracting team.

As a further safety measure, installation of the sea wall units has been limited to ‘low tide windows’, while the work has been completed by the installation of new beach access steps.

Stuart Lawrence, RJ McLeod’s project manager on the scheme, said: “FP McCann worked closely with RJ McLeod and RPS Group to design and manufacture the precast concrete seawall structure, meeting both the detailed time-constrained installation and performance requirements.

"The consistency in quality of the wall units is evident throughout, clearly demonstrating the benefits and advantages of using this precast offsite sea defence solution."