Block Management in Highcliffe

Open coast on Christchurch Bay, from a cliff top rather than a beach frontage. The East coast of Dorset tidal area stops 59 metres short of the built-up area, because the settlement sits above the tidal flood extent. The exposure is salt-laden air and wind-driven rain rather than tidal inundation. External metalwork, fixings, glazing and coatings should be specified for a marine atmosphere. Erosion, not flooding, is the coastal risk that matters here. The shoreline management plan, adopted on 1 July 2011, puts Highcliffe in a policy unit running from Highcliffe to Friars Cliff. It gives hold the line across all three epochs, to 2025, to 2055 and to 2105, noting that detailed consideration will be needed of the case for defending Highcliffe Castle in the long term. Its baseline erosion rate, the rate that would apply if the defences failed, is 1.1 metres a year, or 120 metres over a hundred years. Erosion is currently resisted by defences and the slopes are stabilised. National coastal erosion mapping published in 2025 shows that with no future intervention the main Highcliffe frontage would lose 21 metres by 2055 and 34 metres by 2105 under a present-day climate. On the upper-end climate allowance that rises to 73 metres by 2105. With the shoreline plan delivered every figure is zero, and the frontage is classified as erosion restricted. The defences are a permeable revetment with rock groynes and slope drainage, rated mainly good to fair by the council with an unknown standard of protection. The council's strategy documents disagree on their construction date, one part giving the 1970s and another the 1980s. The Christchurch Bay and Harbour strategy, adopted in December 2025, covers this frontage as a distinct unit between Steamer Point and Chewton Bunny. Appraisal is timetabled for 2030 to 2034 and construction for 2035 to 2039. Its leading national option carries a present value cost of 5.4 million pounds against benefits of 6.9 million, a benefit-cost ratio of 1.28. The strategy states that 18 properties are expected to be at risk within the next 50 years and 191 within the next 100. For a long lease or major works on this frontage, the policy is to hold the line, but the works to deliver it are a decade away from construction, and reserve fund plans should reflect that timetable.

The measurable part of marine exposure is corrosion. A high-salinity coastal atmosphere is category C5-M in the standards, where unprotected steel can lose 200 micrometres in a year. In practice that means the metalwork on a Highcliffe block sets the inspection interval, and the reserve fund follows the inspections rather than a standard cycle.

Almost entirely the lowest band. Of the nine one-kilometre squares covering the settlement, eight are in the lowest class, covering 95.6 per cent of it, where radon measurement is not advised. One is class 3, at 3 to 5 per cent of homes at or above the action level. It covers the remaining 4.4 per cent at the far eastern edge on the Walkford side, where measurement is advised. Only a block in that eastern square needs radon on its compliance list.

That is national advice about the ground, not about the building. The same map excludes basements, cellars and underground spaces at every band, so an enclosed plant room, undercroft or lower-ground flat is still worth a look even here, and whatever is found belongs with the compliance record.

Service charge or accounts query? Email accounts@plymouthblockmanagement.com and quote your development and flat number, or send us your query.