Tree roots near your house: drains, foundations and subsidence

Published 2 November 2026

Most trees near houses never cause a problem. The RHS says that most trees never damage buildings, and that predicting which ones will is unreliable, so its general advice is not to fell a healthy tree just in case. But roots do sometimes play a part in cracked walls, lifted paving and blocked drains, and when they do, it helps to know what is really going on and who to talk to first.

This guide covers how roots cause damage, why the soil under your house matters, what to do if you think a tree is to blame, and how a Tree Preservation Order (TPO) affects things in Stockport and Cheshire East.

How tree roots can cause damage

Subsidence on clay soil. This is the big one. Roots rarely break through sound foundations. The problem is water. On shrinkable clay, a thirsty tree can dry the soil out during a long dry spell, the clay shrinks, and the ground under the footings drops. The RHS says movement usually peaks in late summer, and that around 5–10mm of movement is usually needed before cracks show, typically around windows and doors.

Drains. Roots follow water. The RHS says watertight drains are generally unaffected, but older drains with poor seals and rigid joints are the most vulnerable. A root gets into a leaking joint, grows, and the pipe blocks or the leak gets worse. In other words, the root usually finds a drain that was already failing.

Paving, walls and light structures. Expanding roots can lift paving, garden walls, sheds and garages, but not heavier structures. The RHS says most paving lift happens within 1m of the trunk.

Why the ground under Stockport matters

The RHS is clear that shrinkable clay is the main risk, and that gardens on chalk or sand are very unlikely to have tree-related subsidence. Much of north-east Cheshire and south Manchester sits on glacial deposits. The British Geological Survey even names one after the town: the Stockport Glacigenic Formation, a mix of clay-rich till, sand, gravel and laminated clay that varies a lot from place to place. So two streets in the same suburb can sit on quite different ground.

You can check what is under your own house for free on the BGS Geology Viewer.

The age of the house matters too. The RHS says buildings of up to four storeys built before the 1950s are most at risk because of their shallow foundations, while houses built after 1980 generally have deeper footings and are much less likely to be affected. If you live in an older house, it is worth knowing which group yours falls into.

Which trees drink the most water?

The RHS (drawing on Biddle’s Tree Root Damage to Buildings) lists these as high water demand trees:

• oak, which accounts for the highest number of UK subsidence cases
• poplar, willow and eucalyptus
• cypresses, including Leyland cypress (leylandii)

For high-demand trees, the drying effect can reach a distance equal to the tree’s height. For most other trees it is unlikely to reach more than half the tree’s height. Tall hedges can add to soil drying too, and the RHS suggests keeping them no taller than their distance from the house in subsidence-prone areas. If you have a big leylandii hedge close to the house, our page on leylandii and conifer removal explains your options.

Think a tree is damaging your house? Do this first

1. Call your buildings insurer before anyone cuts anything. The RHS says insurers usually investigate through a structural engineer and a monitoring specialist. Level monitoring over time is more reliable than a one-off soil test. Cracks can have other causes, such as leaking drains, so the cause needs proving.
2. Don’t fell the tree in a panic. On clays that stay dry at depth year after year, the RHS warns that removing a large tree can cause heave, where the soil swells back and pushes the house up. That can need specialist foundation work. The engineer should advise on this before a tree comes down.
3. If it’s your tree and a neighbour says it’s damaging their house, the RHS advises telling your own home insurer (for third-party liability), asking for the reports, and acting promptly if the evidence points to your tree. It also notes that a tree owner can be liable if the tree is “materially contributing” to the damage, even if the tree was there before the house.
4. Don’t rely on a light trim. The RHS says crown thinning doesn’t reduce a tree’s water use enough. For pruning to make a difference, the crown needs reducing by at least 70%, repeated regularly. Felling is usually the most permanent fix when one tree is the main cause.
5. Root barriers are rarely the answer. In theory they work, but the RHS says installing one deep enough is usually not practical.

Roots in your drains: who is responsible?

In the United Utilities area, which covers Stockport and the surrounding towns, you are responsible for the pipes and drains in and around your home up to your property boundary. United Utilities looks after the pipes from your boundary to the public sewer, shared sewers where several homes’ drains join, and the public sewers themselves. See United Utilities’ page on sewers and drains explained.

If a drain is sound, the RHS says no action is needed. If it is leaking and roots have got in, the options are relining the pipe, replacing it with modern plastic pipe, or, as a last resort, removing the tree. A drainage CCTV survey will show where the problem is.

What if the tree is protected?

A TPO doesn’t stop a tree being felled if it is damaging a building, but you still need council consent first, and that includes work to roots. Government guidance says the application must show the tree is a material cause of the problem and that other causes have been ruled out as far as possible. For drains, walls and paving it should be backed by technical evidence from an engineer, drainage surveyor or similar expert. Our guide to whether you need permission to cut down a tree in Stockport explains how to check for a TPO or conservation area, and our protected trees page covers how our teams work with the council.

What if it’s a council or street tree?

Stockport Council says a tree on private land is the owner’s responsibility, and problems with council trees can be reported using its online form. Cheshire East Council, which covers Wilmslow, Poynton, Handforth and Knutsford, says to contact your insurer first, who will make the claim for you. It lists the evidence it expects, including an arboricultural report, crack and level monitoring, trial pits and soil tests, root and drainage investigations, and an assessment of heave if the tree were removed.

If roots are coming from a neighbour’s tree, our guide on neighbours’ trees that overhang your garden covers your rights over roots and branches.

How our teams help

Once your insurer or engineer has said what needs doing, our teams can carry out the work across Stockport, Bramhall, Hazel Grove and the surrounding towns: crown reduction where a tree can stay, tree removal where it can’t, and stump grinding afterwards. We can also take a look at a big tree close to the house and talk you through the options. For other warning signs to watch for, see our guide to signs a tree in your garden could be dangerous. Get a free quote.