Building in the 'Cobalt Belt'
There are few spectacles capable of surpassing the unearthly beauty of a coastal sunset and its brilliant, mirrored coruscations of fiery orange and pink. With large swathes of Britain's scenic south-west coastline off-limits to development as a result of the National Trust's Project Neptune, those areas that become available may seem to be a veritable goldmine for any developer. However, coastal projects face a unique series of challenges throughout their lifecycle that must be accounted for from their inception.
In terms of what constitutes a 'coastal' property for the purposes of this article, I am turning to the climate change commercial search used by our firm as an indicator. It considers the risk of coastal erosion within 2,000m of the coast itself. Additionally, the Australian housebuilder Pivot Homes suggests a focus on the corrosion-susceptible zone along the Australian coast which is "defined mainly by the distance from the marine influence. The strictest requirements concern buildings that are situated within 1km of breaking surf or within 100m of a non-surf coastline, e.g. a river coast."
Pre-Site Acquisition and Site Preparation Considerations:
In order to deliver a coastal project all the way through to handover, potential enabling groundwork must be considered as part of the project's pre-tender phase.
Large portions of the UK's coastline are extremely susceptible to erosion – none more so than the eastern Holderness Coast in Yorkshire which worryingly loses an average of 1.8 metres of ground every year, the fastest rate in Europe. In the south-west, segments of Devon and Cornwall are susceptible, being comprised of a patchwork of differing rock-types ranging from the more durable schist and slate to the frangible sandy clays similar to those that comprise Holderness. This can lead to wild variations in erosion rates across relatively short distances which accounts for some of the spectacular features along this stretch of coast.
The physical stability and history of the neighbouring ground should be a key consideration for developers, even before investing in known hotspots, as well as the likelihood that climate change will exacerbate any instability. In recent years, increasingly extreme weather has accelerated the deterioration and been deemed responsible for a number of collapses across the Jurassic Coast. Abrupt ground destabilisation must be accounted for in the drafting of the building contract; specifically the definitions of Relevant Events and Relevant Matters in the JCT suite of contracts by way of example. As occurred recently at the site of a planned housing development on the Whipsiderry Cliffs near Newquay, existing planning permission and licences can be suspended as a result of sudden changes such as landslips. In such situations, the contract must account for the expense caused by delays, the mandatory re-surveying of the area as well as the potential for the site to be declared no longer usable.
If any form of cliff or shoreline stabilisation work is anticipated, as well as the obligatory planning consent, the applicant will be required to obtain a licence from the Marine Management Organisation (the MMO) to carry out any works/licensed activity under the Marine and Coastal Access Act 2009 and are also likely to require an environmental permit from the Environment Agency to cover any flood defence works. The MMO will evaluate a range of factors including the potential ecological/habitat damage caused by the applicant's proposals. If the application is successful, then the provisions requiring adherence to the conditions of the licence (including the timeframe (which could be restricted by ecological factors such as seabird nesting), permitted work hours and notification requirements) will need to be incorporated into the accompanying building contract. In drafting the contract, one would need to include provisions mandating that the contractor indemnify the client against any breach of the licence by the contractor's (or any of their specialised sub-contractors') activities.
An increasing number of investigations are being carried out into those areas most at risk from rising sea levels, but it is crucial to consider the local plans for coastal defences which could greatly alter the findings and reliability of any ground survey. As of 2025, the current government guidance, as issued by the Environment Agency, is that there are four shoreline policies that can be assigned to a segment of coastline which broadly amount to:
- maintain shoreline in current position;
- managed retreat/realignment;
- push forward (move defences seaward); or
- no intervention.
Ironically, attempts to forestall coastal erosion can exacerbate its effects elsewhere, as has occurred along the east coast, where the construction of groynes has halted longshore drift (the natural movement of beach material by sea currents): although this preserves the coastline in one area, it prevents other beaches from being replenished and thus they (and the buffer that they offer to the coast) are stripped away.
Checking the changing beach width and for the presence of neighbouring manmade structures blocking natural replenishment will be a vital ongoing monitoring aspect of any coastal project, and should therefore be accounted for in the contractor's obligations; reliance upon an initial survey will not be sufficient in such a dynamic environment.
Materials and maintenance
It is standard practice for building contracts to contain detailed provisions regarding the standard of materials to be used in a project including a prohibition on the use of those known to be deleterious to the durability of the buildings or structures. However, a project in the vicinity of a coastline will require specialised contract drafting to accommodate the materials necessary to withstand such a uniquely aggressive environment.
With the spotlight on the renewable energy credentials and efficiency of new developments, the demand for heat pumps and solar panels has greatly increased in recent years. However, the fact that a large portion of the infrastructure (panels, fan units etc) is mounted on the exterior of the building presents a new challenge since they will corrode at a faster rate due to contact with air-borne salt. This can be offset with protective coatings applied during installation but contractual amendments will need to be incorporated to strengthen the contractor's obligation (and to the obligations imposed on sub-contractors engaged on a project) to select materials optimised, where possible, for a coastal environment citing the resistance to corrosion and increased stress due to wind-load.
Salt-tolerance and BNG
In seeking to ensure the suitability of materials for a coastal environment, it is also important to flag the garden areas, both the private/individual allotted segments as well as the common zones, for consideration.
With the drive for biodiversity net-gain, many developers are under pressure to incorporate biodiversity enhancement measures into their projects such as native broadleaf trees, shrubs and wildflowers and will look to engage specialist landscape sub-contractors to design such areas and supply plants. In a similar fashion to the main building contract, construction sub-contracts should contain the obligation to supply salt-tolerant plants and factor the need for sheltered areas into any design.
Final caution
The Law Society now imposes an obligation on solicitors to advise their clients about climate change-related legal risks, specifically coastal erosion where developments are being proposed within close proximity to the shore. Trowers & Hamlins' construction practice has experience of negotiating the full range of building contracts with built-in provisions that account for the whole host of concerns that relate specifically to coastal projects which are laden with complexities, all of which need to be considered well before the tendering process - primarily the volatility of the ground itself.
With an increasingly extreme climate and unpredictable coastal defences, ground stability "snapshot" surveys may only provide a small window of certainty. Ground engineers appear to be becoming increasingly wary of the lack of contractual provisions that relate to delays caused by concealed soil conditions and unpredictable weather, especially within the JCT 2024 suite of contracts.
Building contracts may also be required to incorporate a litany of obligations and restrictions under an MMO licence and oblige contractors to eschew traditional materials where marine-compatible alternatives are available. The engagement and composition of the professional consultancy team is also an area we assist our clients with on their projects and the inclusion of adequate safeguards.
