Subsidence and Commercial Property Insurance in the UK

Ground movement is one of the risks commercial property owners worry about most — and one insurers scrutinise hardest at placement. Here is how the cover works and how a building with a history is presented to market.

What subsidence, heave and landslip cover involves

The three perils are usually grouped together in a buildings wording. Subsidence is downward movement of the ground beneath the building; heave is upward movement, typically when soil that had dried out re-expands; landslip is movement of ground down a slope. Cover responds to damage the movement causes to the insured buildings — cracking, distortion, doors and windows going out of square, and in serious cases structural instability.

Wordings vary considerably. Movement claims commonly carry their own, higher excess. Many policies restrict or exclude damage to yards, car parks, boundary walls, gates and outbuildings unless the main building is damaged by the same event, and damage arising from the normal settlement of newly built structures is generally excluded. Coastal or river erosion is usually treated separately. Because the differences between wordings are real, this is an area where reading the policy — not assuming — matters. For a shorter reference treatment of the topic, see subsidence insurance: the wiki entry.

Why history matters at placement

Insurers rate ground-movement risk largely on what the building has already done. A property that has shown movement in the past — even movement that was investigated, explained and resolved — is a different proposition from one that never has, and insurers ask about it directly on proposal forms and statements of fact.

Under the duty of fair presentation, a history of movement, past monitoring, previous structural repairs or ongoing investigation is exactly the kind of material circumstance that must be disclosed. Staying silent because the movement seemed minor, or happened under a previous owner, is a false economy: if undisclosed history comes to light after a loss, the insurer may be entitled to apply different terms or, in serious cases, treat the policy as if it had been written differently. The safe rule is simple — if the building has moved, been monitored or been repaired for movement, say so, and describe what was found and what was done.

Underpinning and disclosure

Underpinning — strengthening or deepening the foundations so the building bears onto more stable ground — is a permanent alteration to the structure and is always disclosable, however long ago it was done. Insurers will want to know why the building was underpinned, whether the work addressed the whole structure or part of it, and whether it was designed and signed off by an engineer.

An underpinned building is not uninsurable. Once the cause of movement has been properly identified and remediated, some insurers take the view that the repaired structure is well understood and well founded. What makes the difference is the paper trail: engineers’ reports, details of the scheme of works, completion certificates and any guarantees. A building with underpinning and full documentation is a far easier placement than one where the work is visible but unexplained.

Trees, clay soils and the classic contributing factors

Most UK subsidence activity involves a familiar cast of contributing factors. Shrinkable clay soils swell and shrink as their moisture content changes, so buildings founded on clay move more than those on sand, gravel or rock. Trees and large shrubs close to a building draw moisture from the ground and can dry out clay beneath foundations; the effect is worse in prolonged dry weather and with thirsty species. Leaking drains work in the opposite direction, washing away or softening the ground beneath footings.

These factors interact, which is why professional advice matters before acting. Removing a mature tree that has been drawing moisture for decades can cause the clay to rehydrate and swell — producing heave rather than curing subsidence — so arboricultural and engineering advice usually comes before the chainsaw. Simple ownership disciplines help too: knowing what trees stand near the building, keeping drains maintained and investigating cracking early rather than decorating over it.

What monitoring and remediation typically look like

When movement is suspected, the usual first step is investigation and monitoring rather than immediate repair. Crack-width gauges and level surveys record whether the movement is progressive or historic and seasonal; investigation may involve trial pits or boreholes to establish the soil profile and foundation depth, and a CCTV survey of the drains. Because clay soils move with the seasons, monitoring is generally carried through seasonal cycles so the pattern can be read properly.

Remediation then targets the cause: managing or removing vegetation on professional advice, repairing defective drains, and only where the ground genuinely cannot support the building as founded, underpinning — which is a last resort, not a default. Once the structure is stable, the damage itself is repaired, which can range from repointing and redecoration to rebuilding sections of masonry. Throughout, the engineer’s reports become the record the insurance market will later rely on.

How a broker presents a subsidence-history building to market

A building with a movement history is placed on the strength of its file. A broker’s job is to assemble that file — the investigation reports, monitoring results, remediation records, certificates and guarantees — and present a clear narrative: what moved, why, what was done about it, and why the building is stable now. That narrative is put to insurers with genuine appetite for movement-history risks rather than scattered across the whole market.

An illustrative example, for the shape of the process rather than any real case: the owner of an older terraced office building notices cracking, has it investigated, and the engineers trace it to a leaking drain which is repaired, with monitoring afterwards confirming stability. At renewal, the broker presents the full history with the engineer’s closing report, negotiates the movement excess and any exclusions, and secures ongoing cover with the history fully on record — which is precisely where the owner wants to be at claim time.

Frequently asked questions

Does a history of subsidence make a building uninsurable?

Rarely. It narrows the market and shapes the terms — a higher movement excess or specific conditions are common — but a well-documented, properly remediated building can generally be insured. The difficult placements are the ones where movement is suspected but was never investigated, because insurers cannot price what nobody has explained.

Do I have to disclose movement that happened before I bought the building?

If you know about it, yes. The duty of fair presentation covers what you know and what you ought to discover by reasonable search — and surveys, legal packs and underpinning guarantees passed over on purchase are exactly that. Disclosing historic, resolved movement with its documentation is usually straightforward; concealing it is what causes problems.

Is cracking always subsidence?

No. Buildings crack for many reasons — thermal movement, shrinkage of materials, minor settlement — and much of it is cosmetic. That is why investigation comes before conclusions. But recurring, widening or diagonal cracking, or doors and windows sticking out of season, is worth professional attention, and worth mentioning to your broker while it is being looked into.

Apex Insurance Brokers Limited is authorised and regulated by the Financial Conduct Authority (FRN 724952).