Trees and subsidence claims on neighbouring property

If a tree you own is blamed for subsidence at a neighbouring property, the claim against you is a civil one in nuisance, and the planning system is what stops you simply felling the tree to make it go away. A tree subsidence claim neighbour dispute therefore runs on two tracks at once: a private law argument about causation and remedial cost, and a public law question about whether the council will allow the works the insurer is demanding. The two tracks rarely talk to each other, and tree owners get caught in the gap.

Slow down before you agree to anything. Removal is often the worst available answer.

How a subsidence claim against a tree owner works

The usual claim is in nuisance. Roots drawing moisture from shrinkable clay cause the soil to contract, foundations move, and the building cracks. Where the damage is continuing and the tree owner has been told about it and given a chance to deal with it, the courts have allowed recovery of the cost of remedial works, including foundation strengthening, following the reasoning in Delaware Mansions v Westminster City Council.

Three things have to line up for a claim to succeed: that damage of that type was reasonably foreseeable, that the tree in fact caused the movement, and that you were given notice and an opportunity to abate. Foreseeability is judged on what a reasonable owner in your position knew or should have known, which is why a letter from a loss adjuster changes your position even if you dispute it.

Responding matters more than agreeing. Silence after notice is the thing that turns a contested causation argument into a straightforward liability finding.

Evidence needed to link the tree to the damage

Most claims arrive with an engineer's report asserting clay shrinkage and a photograph of your tree. That is a hypothesis rather than proof, and the evidence a court expects is more demanding.

A properly evidenced claim will include level monitoring at the affected building over at least a full seasonal cycle, so that the characteristic summer downward movement and winter recovery can be seen. It will include trial pits establishing foundation depth and type, soil sampling tested for plasticity index and moisture content with depth, and root identification from samples taken beneath or beside the foundations, either microscopically or by DNA. It will place the tree by species, height and distance, and relate that to published water demand categories.

Ask for all of it before conceding anything. Monitoring over a single summer, no soil testing, or roots identified only as "tree roots" leaves an argument worth running. Clay shrinkage also has causes that have nothing to do with trees, including leaking drains and historic excavation.

Consent where the tree is protected

Here is the pinch point. Where the tree has a Tree Preservation Order, or stands in a conservation area, you cannot lawfully fell or heavily prune it just because an insurer asked you to.

For a protected tree you apply to the council for consent under the 2012 Regulations. In a conservation area you give six weeks notice under section 211 of the Town and Country Planning Act 1990, and the council may respond by making an Order. Either way the council will want the subsidence evidence, not a summary of it, and a tree officer who receives a felling application supported by one page of assertion will refuse it.

The Regulations contain exemptions, and one of them covers works urgently necessary to remove an immediate risk of serious harm. Another covers works necessary to abate a nuisance in the legal sense. Both are narrow, both put the burden of proof on the person carrying out the works, and both are frequently misread. Felling a protected tree on the strength of a misjudged exemption is an offence, and our note on the penalties for damaging a protected tree sets out what follows.

When an insurer asks for removal

Insurers act for the claimant and their interest is in closing the claim at the lowest cost. Removal of the tree is usually the lowest-cost route for them and not necessarily the right one for anyone else.

You are entitled to ask for the alternatives to be costed. You are also entitled to point out that the council's decision is not within your gift, and that a refusal of consent is a material fact in the dispute rather than an excuse. Where the council refuses consent for the works an insurer says are necessary, compensation may be payable by the council in certain Tree Preservation Order cases, which is worth investigating before you accept liability yourself.

Say all of this in writing and keep the correspondence. A tree owner who engaged, commissioned advice and applied for consent is in a very different position from one who ignored three letters.

Engineering alternatives to felling

Removal is not the only remedy, and on clay it carries its own risk.

Felling a mature tree on shrinkable clay can trigger heave as the soil rehydrates over several years, and heave damage often costs more to repair than the original subsidence. Any engineer recommending removal next to a building on shallow foundations should address that directly.

The realistic options are these:

• a managed crown reduction programme on a stated cycle, reducing water demand while keeping the tree
• a root barrier between the tree and the building, installed to a depth related to the soil profile
• underpinning by mass concrete or mini piles, which fixes the building rather than the cause
• superstructure repair alone, where movement has stabilised
• monitored inaction, where the evidence points to cyclical rather than progressive movement

Get an arboriculturist to advise on which of these is deliverable for the tree, and a structural engineer to advise on the building. A survey to BS 5837:2012, which sits behind the Tree Survey report type, gives the baseline data both of them will ask for.

Common law abatement and its limits

A neighbour may cut back roots and branches that cross the boundary, at their own cost, back to the boundary line and no further. The cut material remains your property and should be offered back.

Three limits apply. The right does not extend to works that would kill or destabilise the tree. It does not override tree protection, so a neighbour cutting the roots of a protected tree without consent commits the same offence you would. And abatement carried out negligently, causing the tree to fail, exposes the neighbour to a claim from you.

Root severance close to a trunk can destabilise a mature tree, which becomes your liability if it then falls. If a neighbour tells you they intend to excavate along the boundary, get an arboriculturist on site before the digger arrives.

Records worth keeping as a tree owner

Keep a file for every mature tree near a boundary. Photographs with dates, planting or first-recorded dates where known, a record of every inspection with the inspector's name and qualifications, every pruning specification and the date it was carried out, any Tree Preservation Order reference, and all correspondence with neighbours, insurers and the council.

That file is what converts "we had no idea" into a defensible account of reasonable management. Landlords with several properties should hold it centrally rather than in individual property files, and refresh inspections on a stated cycle. A planting and management schedule of the kind that sits inside a Landscape Strategy does the same job on a development site.

But the single most useful habit is answering letters. Notice starts the clock, and a reasoned reply within a fortnight protects you far better than silence.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it.

You can see which reports a site with mature trees needs from a postcode. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.