Work is taking place on nearly £3 million of works to upgrade the sea wall on the north end of Largs Promenade - which has resulted in a significant section being closed off to the public.

This part runs along the northern seaward section of Largs Bay, for approximately 300 metres between Aubery Crescent and the existing RNLI slipway.

The existing seawall is in a state of disrepair and needs to be upgraded.

It was originally constructed in the 1970s as a replacement facing for an older seawall, and has deteriorated over time due to repeated exposure to seawater.

North Ayrshire Council wants to ensure that the seawall continues to provide optimum protection and support against wave activity and coastal erosion. The best design solution is to replace/encapsulate the existing seawall.

Tell us more about the contractor involved in the project

In June 2023, RJ McLeod was appointed as the main contractor for this project.

The company is one of Scotland's largest privately owned civil engineering and building contractors based in Glasgow. For over 70 years it has successfully delivered major projects, and it has a proven track record in Britain’s civil engineering and building infrastructure.

Throughout the 1950s the company gained a reputation as an accomplished hydro scheme contractor and held the European tunneling record on  construction of the Breadalbane Tunnel. The company was heavily involved in the New Town era of the 1960s and 1970s with the construction of many a Highland road added to its portfolio.

Largs and Millport Weekly News: How the new sea wall and extended prom will look when completeHow the new sea wall and extended prom will look when complete (Image: NAC)

The early 1980s saw RJ McLeod venture into the petro-chemical industry, with a contract for Shell at Braefoot Bay, its first working to a formal Quality Assurance and Quality Control Standard. In this era the company also attained another record – this time for Britain’s biggest single concrete pour outside the oil industry – a 1,300m3 pour for the construction of a 5-span bridge deck on the Ballinluig section of the A9.

Later in the 1980s the company played its part in the cultural and economic renaissance of Glasgow – the city where the company was first registered and where its head office is based – with contributions to the infrastructure of the Scottish Exhibition and Conference Centre (SECC), groundworks, landscaping and foundations at the Glasgow Garden Festival and groundworks and substructure of the Glasgow Royal Concert Hall.

How long are the works expected to last?

The work began on site in July 2023 and is set to last until spring 2024.

Work will extend 300m along the existing seawall with the replacement structure extending to a footprint of 0.24ha (2,400 sqm) and a height equal to the existing seawall, varying from approximately 1m to 4m.

What do the specific works involve?

The works will involve the removal of existing steps and installation of new steps along the seawall structure.

It will see the installation of precast concrete caisson units to be infilled with granular material to facilitate subsequent installation of new concrete seawall units.

Granular backfill material will be used between the existing seawall and the new replacement structure with suitable drainage installed and concrete or asphalt material used to surface the said backfill; and the reinstatement or installation of a new handrail along the promenade.

Largs and Millport Weekly News: Sea wall image projectionSea wall image projection (Image: NAC)

The total length of time to complete the proposed works is estimated to be between 4-6 months depending on tidal restrictions.

Beach material will be excavated to facilitate the placement of the concrete caisson units.

A foundation for the replacement seawall structure will be excavated to low water level and a lean mix concrete added.

The precast concrete caisson units will then be installed on top of this material by a crane, and the new concrete seawall units will be placed on top.

An excavator working from the promenade side will place and compact backfill between the existing seawall and the replacement seawall structure and rock will be layered to the front of the replacement seawall structure.

How will it compare to the original prom when finished?

The new seawall replacement structure will have similar construction, level and wave reflective properties to the existing seawall. The proposed works will be undertaken during low tide when there is no water within the intertidal zone, therefore minimising the potential impacts of pollution on the water environment and reducing the significance of any noise generated by the piling and demolition phases.