Balbriggan Harbour is a listed 18th century masonry harbour and the options considered needed to be in keeping with the existing architecture and be approved by the FCC Heritage and conservation officer. The partial collapse of the quay was attributed to an external source which caused scouring of the harbour bed and undermining of the foundations.

Following the initial review of the collapse whilst options for repair were being considered and discussed Royal Haskoning designed and supervised the ground investigations in order to identify the condition of the founding stratum.

For the ensuing design of the repairs of the preferred option Royal Haskoning used a variety of techniques to address the problem including underwater concreting to form the foundations, sheet piling and the addition of new fill material to maintain the level of the quay. Grout injection of the existing fill was also used to stabilise the quay wall on either side of the collapsed section.