Cardiff faces £9.54m extra bill for delayed coastal defences

Cardiff Council faces an extra £9.54m contribution to a coastal-defence scheme whose completion date has moved from October 2026 to August 2027, according to papers presented to councillors on 10 September. The forecast total is £45.48m, compared with an approved budget of £35.94m. The Welsh Government contribution stays at £30.55m in that forecast, leaving the council to meet the whole increase. These are projected costs, not a final account of spending.

What the defences are intended to protect

The council says the completed scheme will protect 1,116 homes and 72 businesses against a one-in-200-year storm event, with a 40% climate-change allowance. It also covers highways, utilities and other coastal infrastructure. The September presentation reported about 80% of physical work complete, including finished rock armour and substantial sheet piling. That is the position reported then, rather than a fresh inspection of the site.

Why the forecast has risen

Officers identify £2.6m in costs linked to delayed environmental approvals. The presentation says the construction contract began before the permissions were secured because awarding it was necessary to retain Welsh Government funding. Unsuitable ground conditions required changes to the rock-armour design. Officers say an initial £15.5m increase for that change was reduced to £5.5m through redesign. A different piling method to keep one lane of Lamby Way open adds another £1m. Those rounded figures describe the principal pressures, rather than an exact reconciliation of every pound. The council’s planned contribution rises from £5.39m to £14.93m. Its March 2026 capital programme included £10m of additional borrowing towards the identified costs, split between two financial years.

The dates and the questions still open

The revised completion date in the presentation is 12 August 2027, 285 days after the original 31 October 2026 deadline. The document attributes 270 days to approval delays but does not separately explain the remaining 15. For Lamby Way, the September programme scheduled piling from 5 October within a 20-week work programme, with one lane closed to provide working space. The papers warn of local disruption. They do not establish the live traffic arrangements on any particular day. In a letter dated 14 September, the scrutiny committee asked for confirmation of the completion date, remaining delivery risks and whether approval or design problems could reasonably have been identified earlier. It recommended a lessons-learned review after the contract ends. The papers also consider replacing a potential £3.2m river-edge stabilisation intervention with monitoring and later action if needed. That is a possible saving, not a confirmed reduction in the published forecast. The committee asked what would trigger intervention and how future work would be funded.