A tree survey for subsidence checks whether vegetation is actually contributing to movement in a building, rather than assuming it is. Our surveyors record which trees and shrubs are present, their species, size and distance from the affected structure, and set that against what is known about the soil and the pattern of damage. The aim is evidence: either the trees are plausibly implicated and a clear course of action follows, or they are not and you avoid felling a tree that was never the problem. Either way, the report gives you something an insurer, engineer or council can work with.
Why soil matters more than the tree
Subsidence linked to vegetation is largely a story about soil. Trees on shrinkable clay soils can be implicated in subsidence, because clay of that type changes volume with its moisture content. Where a building’s foundations sit in shrinkable clay and vegetation is drawing moisture from that soil, seasonal movement can follow. On other soil types, a tree close to a house may be entirely innocent, however large it looks from the kitchen window.
That is why the first questions in a subsidence survey are not really about the tree at all. What is the soil? Where is the damage, and does its pattern fit seasonal moisture movement? Only then does the vegetation evidence carry weight.
What the survey actually records
A tree survey for subsidence is a structured piece of evidence gathering, not a walk round the garden with an opinion at the end. Our surveyors typically record:
- Every relevant tree and shrub, including vegetation on neighbouring land where it can be seen, since a tree belongs to the land its trunk stands on and responsibility follows ownership.
- Species, height, spread and condition, because species differ in how much water they draw and how they respond to pruning or removal.
- Distance from the affected structure, measured, not estimated.
- The site context, including drains, hard surfacing and anything else that affects soil moisture around the building.
- Protection status, because what you are allowed to do next depends on it.
The report sets this out plainly so that everyone involved, including your insurer and any structural engineer, is working from the same facts.
Root investigation: putting roots at the scene
Where the case needs it, the next step is a root investigation. Distance and species suggest which trees could be involved; roots recovered from beneath or beside the foundations show which ones actually are. Samples taken from trial pits or bores near the damage can be identified, and identification ties the roots to a particular species and, from there, to particular trees on or off the site. Combined with soil information, this turns “the oak is close, it must be the oak” into a finding that stands up to scrutiny.
That matters because the remedy is rarely free of consequences. Felling or heavy pruning of the wrong tree loses the tree and leaves the real cause untouched.
Why felling first is the wrong move
The instinct when cracks appear is to remove the nearest big tree. There are two good reasons to pause.
First, the tree may be protected. TPO trees need council consent before works, and works to trees in a conservation area need six weeks written notice to the council. Penalties for unauthorised works on protected trees can include unlimited fines. Overhanging branches may usually be cut back to the boundary, but not when the tree is protected, so check first. You can run an address through our free protected tree checker, which reads the national planning dataset; it is indicative only, and the council register is definitive, so confirm with your council before any work. This is general information, not legal advice.
Second, removal is a bigger decision than it looks. If trees are implicated because of the moisture they draw from shrinkable clay, then taking one out changes the moisture conditions in that soil too, and that change is worth understanding before it is made. A survey lets the decision, whether that is removal, staged reduction or leaving the tree alone, rest on evidence rather than instinct. Landowners owe a duty of care for their trees, and a documented survey is also the sensible way to show that duty has been met.
Independent findings, whoever does the work
Our subsidence surveys are priced and delivered on their own. The findings are what the trees and the evidence support, nothing more, and you are free to take the report to any contractor you choose. If works are recommended and you would like us to carry them out, we can, as an ARB Approved Contractor (AC2637), but the report does not depend on that. We carry £1m professional indemnity cover, quotes come within one working day, survey visits are within days, not weeks, and the price we quote is the price you pay.
If you are seeing cracks and there are trees nearby, tell us what is happening using the free scope check form at /tree-surveys/#survey-enquiry, or call the office on 07884 274693. We serve Preston, Lancashire and the North West from our base at Freshfield Farm, Freckleton.
