Underpinning and Foundation Contractor Insurance
Underpinning is deliberately removing the ground beneath a standing building, in sections, and it is carried out on buildings that are already moving.
Working Under A Building That Is Moving
That is the whole of the risk. Nobody underpins a sound house. The work exists because a building has subsided, heaved, or been undermined, which means the structure arriving on site is already cracked, already distorted, and already the subject of a claim or a dispute. Then sections of its support are excavated and replaced, one at a time, while it stands.
In a terrace or semi it gets harder again, because the building being underpinned is physically attached to somebody else's, and movement does not respect a party wall.
What Underpinning Contractor Insurance Covers
Public liability
Injury and damage to third parties, including the occupiers and the attached neighbours. £5 million is a floor and £10 million common on insurer panel work.
Ground movement and further damage
The cover that decides whether a policy works here. Further movement, cracking or collapse during or after the work, which many wordings restrict.
Damage to the building worked on
The structure is the thing you are working on and it is already compromised, which is exactly where wordings draw exclusions.
Neighbouring and attached property
A party wall and an attached house, whose owner has no contract with you and every reason to complain.
Employers' liability
Compulsory at a £5 million statutory minimum. Excavation beneath a standing structure, confined pits, and working under load.
Professional indemnity
Underpinning design, depth, sequencing and whether underpinning is the right remedy at all are engineering judgements. Mechanics on our professional indemnity page.
Contract works
The partly completed underpinning and any temporary support, which is carrying a building while incomplete.
Where The Cover Stops
Wordings differ between insurers, so treat these as the usual position rather than as universal fact. Where one of them matters to you, it is worth checking on your own schedule before you need to.
Pre-existing damage
The building is already cracked, which is why you were called. Without a detailed record, every crack becomes attributable to the work.
Further movement during the work
Underpinning can cause movement while relieving it. Whether further damage during the works is covered needs establishing explicitly.
Sequencing and pin length
Opening too many bays, opening adjacent bays, or going to the wrong depth is a design and method failure rather than a workmanship one.
Partial underpinning
Underpinning part of a building can transfer movement to the unpinned part, which is a predictable consequence rather than bad luck.
Trees and the cause of the subsidence
Treating the symptom without addressing a tree or a leaking drain means movement continues and the remedy is blamed.
Working in occupied homes
Most underpinning happens with the family living there, through pits in their floors and dust in their rooms.
Record Every Crack Before You Start
No trade on this site has a stronger case for a comprehensive pre-work record, because the building is damaged before anybody arrives.
An underpinning job starts with a structure that has cracked, dropped, distorted doors and windows, separated at a junction, or pulled away from a neighbour. The owner, their insurer, a loss adjuster and frequently a solicitor are already involved, and everybody has a view about what the damage is worth. Once bays are open and work is underway, nobody can distinguish existing damage from anything the work caused, and further movement during underpinning is a recognised possibility rather than a remote one.
So the record has to be better than a few photographs. Every elevation and every room, crack widths measured with gauges and position references, door and window operation noted, level readings where available, internal and external, and the same for the attached neighbour. Share it with the engineer and the adjuster and get it acknowledged. The cost is a morning. The alternative is defending an allegation about a crack you cannot prove was there, in a building whose owner is already in a claims process.
The Sequence Is The Engineering
Underpinning fails in a small number of well understood ways, and almost all of them are about how and in what order the ground was removed.
A building standing on a foundation that is being removed in sections relies entirely on the sequence: how wide each bay is, how many are open at once, whether adjacent bays are opened together, how long a bay stays open, how it is backfilled and pinned, and how load is transferred to the new work. Get it wrong and the wall above a bay drops, a corner fails, or the building cracks in new places. Depth matters just as much: underpinning to a level still within the influence of a tree or a desiccated clay horizon achieves nothing.
Which puts the design at the centre. Where an engineer specifies the scheme and you execute it, your exposure is the execution and the record of what you built is your defence. Where the scheme is yours, which is common on smaller residential work, a failure traces to a calculation and a method rather than to a bricklayer, and that is professional indemnity. Either way, record bay widths, sequence, depths reached and the condition found in each pit, because the ground encountered frequently differs from the investigation.
Fixing Half A Building
There is a predictable consequence in this trade that generates disputes, and it is worth explaining to a client before starting rather than after.
Underpinning part of a building stiffens that part and leaves the rest as it was. If the cause of movement continues, the unpinned section carries on moving, and the result is new cracking at the junction between the pinned and unpinned parts. That is not a failure of the work; it is what partial underpinning does. Clients and sometimes insurers nonetheless experience it as the underpinning having caused fresh damage, and the conversation afterwards is difficult because the new cracks are real.
So the explanation belongs at the start and in writing. Where a scheme is partial, say what that means and what may happen at the junction. Where the cause of the movement is a tree, a leaking drain or a neighbouring influence that is not being addressed, say that underpinning treats the effect and not the cause, and record it. And where a client or an adjuster chooses a cheaper partial scheme against your advice, record the advice and the decision. That paragraph is worth more than any clause in the policy.
The Family Is Still Living There
Most residential underpinning happens in an occupied house, which makes it one of the more intrusive jobs in construction.
Bays are excavated through floors or against external walls, spoil comes out through the property or round it, concrete goes in, and the work takes weeks. Services are disturbed, floors come up, dust travels, and the household is living in a building they already believe is damaged, in a claims process, with contractors they did not choose. Complaints are frequent and they are rarely about the structural work: they are about dust, access, services, and a programme that moved.
So housekeeping and communication are part of the job. Sheeted and protected routes, floor protection, services mapped before any pit is opened and reinstated properly, a written programme including when water or heating will be off, daily clean down rather than weekly, and a named person the household contacts. Photograph the access route and every room before starting. On insurer panel work, a complaint about mess reaches the adjuster and affects whether you get the next job, which makes it commercially expensive as well as awkward.
How To Choose A Broker For Underpinning
Two clauses decide it: ground movement, and damage to the building you are working on. We are an FCA regulated broker and will not tell you we are the best choice. These are the questions that decide it.
Is further ground movement during the work covered?
Underpinning can cause movement while relieving it, and many wordings restrict subsidence and ground movement.
Is damage to the building you are working on covered?
The structure is the thing you are working on and it is already compromised, which is exactly where exclusions sit.
Is attached neighbouring property plainly included?
In a terrace or semi, the complaint comes from an owner with no contract with you.
Is the underpinning design covered as advice?
Sequence, bay width and depth are engineering judgements, and on smaller residential work the scheme is frequently yours.
Does the limit match insurer panel work?
£5 million is a floor and panel and managing agent work generally specifies £10 million.
Has the condition survey been raised?
A broker who insists on one before you start understands that the building was cracked before you arrived.
Factually, here is what we do against those questions. We establish how ground movement and damage to the building being worked on are treated, because those two clauses decide whether a policy insures this trade at all, we confirm attached neighbouring property is plainly covered, we arrange professional indemnity where the scheme is yours, and we tell you to hold a measured condition record of the property and its neighbour before a single bay is opened. We are a broker, so it goes to several insurers rather than one.
We also insure piling contractors, basement contractors and tunnelling contractors, so ground movement and buildings that are already moving are familiar ground here.
What Moves The Price
Every policy is priced on the business behind it. These are the things that move the premium:
- Whether ground movement and further damage is covered
- Whether you design the scheme or execute an engineer's
- Methods used, from mass concrete to mini piling and resin
- Terraced and semi-detached work against detached
- Whether work comes through insurer panels
- Whether properties are occupied during the work
- The limit of indemnity your contracts require
- Claims history, particularly further movement
We are a broker, so we take it to several insurers rather than quoting one. Call 02382 000820 for a quote.
What We Need To Quote
- The methods you use and typical depths
- Whether you design schemes or work to an engineer's design
- The proportion of terraced and semi-detached work
- Whether work comes through insurers or loss adjusters
- Whether properties are occupied during works
- Your condition survey procedure before opening bays
- The limit of indemnity required, and who requires it
- Any claims in five years, including further movement
Cover that often goes with this
The gaps we most often find sitting next to this policy.
- Piling contractorsMini piling for underpinning, and the same movement risk.
- Basement contractorsRemoving ground beneath a house at larger scale.
- Tunnelling contractorsSettlement in buildings above the work.
- Damp proofingLeaking drains and water as a cause of movement.
- Tree surgeonsTrees as the cause, and heave if one is removed.
- Talk to a brokerAsk whether damage to the building worked on is excluded.
Common questions
What insurance do underpinning contractors need?+
Public liability at £5 million as a floor and £10 million on insurer panel and managing agent work, written so damage arising from ground movement is covered and so damage to the building you are working on is not excluded, because those two clauses decide whether a policy insures this trade at all. Then attached neighbouring property plainly included, contract works covering partly completed underpinning and temporary support, employers' liability at a £5 million statutory minimum, and professional indemnity where the scheme is yours.
Am I liable for cracks that were already there?+
Only if you cannot show they were, which is why this trade has the strongest case for a detailed pre-work record of any on this site. The building has already cracked, dropped and distorted, and an owner, an insurer, an adjuster and sometimes a solicitor are already involved with views about what the damage is worth. Once bays are open nobody can distinguish existing from new. So measure crack widths with gauges and position references across every elevation and room, note door and window operation, include the attached neighbour, and get it acknowledged.
Can underpinning itself cause movement?+
Yes, which is why the sequence is the engineering rather than a method detail. A building standing on a foundation being removed in sections relies entirely on how wide each bay is, how many are open at once, whether adjacent bays are opened together, how long they stay open, and how load transfers to the new work. Get it wrong and the wall above a bay drops or the building cracks in new places. Depth matters equally: underpinning to a level still within a tree's influence achieves nothing.
What happens if we only underpin part of the building?+
The unpinned part carries on moving if the cause continues, and new cracking appears at the junction between the pinned and unpinned sections. That is what partial underpinning does rather than a failure of the work, but clients and sometimes insurers experience it as fresh damage caused by you. So explain it at the start and in writing: what a partial scheme means, what may happen at the junction, and where underpinning treats the effect rather than the cause such as a tree or a leaking drain. Record any cheaper scheme chosen against your advice.
Do underpinning contractors need professional indemnity?+
Where the scheme is yours, yes, and on smaller residential work it frequently is. Somebody decides the underpinning type, the bay widths and sequence, the depth, and whether underpinning is the right remedy at all rather than drainage repair or tree management. If an engineer specifies and you execute, your exposure is execution and the record of what you built defends you. If the scheme is yours, a failure traces to a calculation and a method rather than to a bricklayer, which is advisory.
Who insures underpinning contractors in the UK?+
A narrow specialist market, because ground movement and damage to the structure being worked on are both restricted in most general wordings, and the buildings are already damaged before the contractor arrives. It is placed through brokers. What separates placements is whether further ground movement during the work is covered, whether damage to the building being worked on is excluded, whether attached neighbouring property is plainly included, and whether the design is separated from the execution.
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