The Hidden Risks Next Door – Party Walls & Non-Negligence Cover | JCT Insurance
When you take on a building project, your focus is usually on your own property – the plans, the budget, and the work that needs doing. But your responsibilities extend beyond your boundary line.
If your works cause damage to a neighbour’s property, whether through negligence or even when no one is at fault, you may still have to pay for repairs. That’s why understanding party wall agreements and the role of non-negligence insurance is so important.
When Party Wall Agreements Apply
In England and Wales, the Party Wall etc. Act 1996 requires you to have a party wall agreement if your works will:
- Involve work on an existing shared wall (such as in terraced or semi-detached homes)
- Be within 3 metres of a neighbouring building and go deeper than its foundations
- Be within 6 metres and involve excavation intersecting a 45° line from the bottom of the neighbour’s foundations
A party wall agreement is a formal document that sets out the rights and responsibilities of both you and your neighbour during the works. It’s usually drawn up by a party wall surveyor.
What a Party Wall Agreement Doesn’t Do
A common misunderstanding is that once you have a party wall agreement in place, you’re protected from claims. This is not the case.
The agreement helps to:
- Set out how the work will be done to minimise risk
- Record the condition of the neighbour’s property before work starts (so existing cracks aren’t blamed on you)
But it does not:
- Pay for any damage that occurs
- Replace the need for proper insurance
The Range of Risks to Neighbouring Property
Damage to a neighbour’s property can occur in many ways, for example:
- Minor cosmetic damage – paint splashes, cement staining, broken paving
- Cracking – from vibrations caused by pile driving or demolition
- Structural movement – changes to your foundations affecting the neighbour’s building
- Water ingress – from changes to drainage or excavation work
- Land slip or heave – from removing trees or altering soil support
Some of these risks are foreseeable but unavoidable, even with the best methods and equipment.
Real-World Example
A homeowner undertook a basement excavation on their mid terrace, Victorian property. Despite following the engineer’s method statement exactly, the vibration caused the lath and plaster ceilings to collapse in the two adjoining properties three months after the remedial work required under the party wall agreement was completed. There was no negligence – everyone did everything right – but the damage had clearly been caused by the vibration that occurred during the basement works.
The property owner had to pay for repairs. Because this damage was not foreseeable and the damage occurred during the policy maintenance period, the cost was met by the non-negligence policy.
When Liability Insurance Isn’t Enough
If damage is caused by someone’s mistake – for example, a contractor ignoring the engineer’s instructions – the contractor’s public liability insurance may cover the cost.
If the damage is due to a design flaw, the architect’s professional indemnity insurance might respond.
If the damage is caused because the structural engineer got the calculations wrong, or gave incorrect instructions in the method statements, then the cost could be down to their professional indemnity cover.
But if no one is at fault, these policies won’t pay out. That’s where non-negligence insurance comes in.
What Is Non-Negligence Cover?
Non-negligence cover (sometimes called Party Wall Insurance or Section 2(b) cover) protects you against the cost of repairing damage to third-party property caused by your works, even when no negligence is involved.
It’s designed to cover:
- Subsidence or movement of neighbouring buildings
- Damage from vibration or weakening of support
- Landslip or heave following excavation or tree removal
Another Real-World Example
A homeowner carried out underpinning work to stabilise their own property. The work was designed and overseen by a qualified engineer, and the contractor followed the method statement precisely. Despite this, unexpected ground movement occurred, causing a crack to appear in the neighbouring property’s wall. There was no negligence, but the repairs cost more than £18,000. The homeowner’s non-negligence policy covered the full amount, allowing the project to continue without dispute.
When You Should Consider Non-Negligence Insurance
You should speak to your insurance advisor about this cover if your works involve:
- Excavation near neighbouring buildings or hard landscaping such as swimming pools or tennis courts.
- Basement construction or underpinning
- Piling or heavy vibration work
- Removing or cutting back large trees
- Altering retaining walls or boundary support
The closer and more complex the works, the greater the risk – and the more important this cover becomes.
How to Protect Yourself and Your Neighbours
- Get a condition survey of neighbouring properties before work starts.
- Follow method statements provided by your engineer or architect exactly.
- Maintain open communication with neighbours about what’s happening and when.
- Arrange appropriate cover, including non-negligence insurance where appropriate.
Key Takeaways
- A party wall agreement sets rules – it doesn’t pay for damage.
- You can be liable for damage to neighbouring property even without negligence.
- Some damage to neighbouring properties will be foreseeable – you can’t insure against your liability for repairing this.
- Non-negligence cover fills the gap left by standard liability policies.
- Always seek expert advice on the right level of cover before work begins.
Need expert advice on protecting your project and your neighbours?
Call 01825 745 410 – every call is answered by a qualified advisor.
Email enquiries@jctinsurance.com for a fast, personal response.
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