Common questions
What to do when something looks wrong with your home
Send a short description of what you have noticed. A specialist firm will read it and tell you whether the signs point to ground movement or something minor. There is no charge for that first look.
Does every crack mean subsidence?
Most cracks in plaster are caused by normal drying, temperature changes or small amounts of settling after a house was built. Hairline cracks along plasterboard joints or around window frames rarely point to anything serious.
A crack that matters tends to be wider than a few millimetres, runs diagonally through brickwork rather than following mortar lines, or appears suddenly after dry weather. Doors and windows that stick without any change in humidity can also signal movement below the floor.
The difference between harmless shrinkage and ground movement cannot be settled by looking at the wall alone. A structural engineer or surveyor needs to measure the width over time and check the soil beneath the foundations before anyone can say what caused it.
How long should I watch a crack before acting?
If a crack is thin enough to slide a piece of paper into but nothing thicker, marking its ends with a pencil and checking monthly is a reasonable start. Many settle on their own once the seasons change and moisture returns to the clay.
But if the gap widens within weeks, if new cracks appear nearby, or if a door frame distorts enough to jam the latch, waiting longer risks further damage. Specialist firms use monitoring gauges fixed across a crack to record tiny movements over months. Those readings show whether the ground is still shifting or has stopped.
There is no universal safe waiting period because Kent sits on several different types of soil. Weald Clay shrinks dramatically in summer. Chalk can dissolve slowly where water flows underground. The right moment to ask for help depends on the ground beneath your specific home.
Will my buildings insurer pay for this?
Subsidence claims fall under most standard buildings insurance policies, but the insurer needs evidence that ground movement caused the damage before they accept liability. That usually means a report from a structural engineer or a loss adjuster appointed by the insurer.
Calling the insurer early is sensible because many policies require notification as soon as you suspect a problem. Delaying could give them grounds to question the claim later. But calling them does not commit you to making a formal claim straight away.
If the movement is minor and the repair cost falls below your excess, paying privately might be cheaper than risking higher premiums. A specialist firm can assess the damage and give a figure so you can compare the two options before deciding.
What happens during a site inspection?
A specialist visits the home, walks around the outside walls and checks the interior rooms where damage shows. They note crack widths, directions and positions relative to doors, windows and corners. They also look at drainage, trees and any recent building work nearby.
Sometimes visual clues are enough to form a working theory. Other times trial pits or boreholes are needed to reach the soil beneath the foundations. Root samples may be taken if a tree is suspected of drawing moisture from clay.
The goal is to find the cause, not just describe the symptoms. Once the cause is pinned down, the specialist writes a report setting out what is happening and what work would stop it. That report goes to you, your insurer, or both.
Do I need underpinning?
Underpinning is only one way to deal with subsidence, and it is used less often than people assume. If a leaking drain washed soil away, fixing the pipe and filling the void might be enough. If a tree caused clay to shrink, managing the roots or removing the tree could stabilise the ground without digging beneath the footings.
When foundations genuinely need deepening, the method depends on the soil and access. Traditional mass concrete underpinning involves digging sections below the existing footing and pouring new concrete. Resin injection pumps expanding material into weak ground to fill voids and compact loose soil. Screw piles drive steel shafts down to a stable layer, bypassing the moving ground entirely.
A specialist firm decides which approach fits after inspecting the site. Each method suits different conditions, and the choice depends on what the ground investigation reveals rather than assumptions about cost.
Reading the signs around your home
The same visible symptom can stem from different causes depending on the soil, nearby trees and how the house was built. Context determines what a crack actually means.
- Diagonal crack wider at the top
- Often points to foundation movement on one side. Measuring it over several months shows whether the shift is ongoing or has stopped.
- Doors sticking in summer only
- Suggests seasonal swelling in timber or clay heave. A pattern repeating each year differs from progressive movement needing repair.
- Gaps appearing around window frames
- Can indicate the wall is pulling away from the frame. Checking the surrounding brickwork reveals whether the whole wall has shifted.
- Cracks in a concrete garage floor
- Frequently caused by washout beneath the slab or poor original compaction. A core sample or ground radar scan clarifies the void size.
- Steps cracking along mortar lines
- Mortar is weaker than brick, so cracks follow it naturally. Width and direction matter more than the path the crack takes.
Typical costs for ground and foundation work
Prices vary because every home sits on different ground, has different access constraints and requires a different scale of intervention. Depth of excavation, soil type and proximity to trees all push a job toward one end of a range or the other.
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Resin injection per square metre
£150 to £350
Depth of treatment, soil type and how much void space needs filling beneath the slab.
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Concrete floor repair per room
£800 to £2,500
Whether the slab needs partial replacement or just surface levelling and crack stitching.
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Screw piling per pile
£250 to £600
Required depth to reach load-bearing strata and the diameter of the helical plate used.
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Traditional underpinning per metre
£1,500 to £3,000
Excavation depth, access for spoil removal and whether drainage must be diverted during the dig.
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Full structural survey
£750 to £1,500
Size of the home, number of trial pits required and complexity of the final report.
These figures indicate typical market costs for this kind of work. Nothing here is a quotation. Only a site inspection can settle a price for a specific home.
Tell us what you have noticed
Write down where the crack is, how wide it looks and when you first saw it. A specialist firm will review those details and advise whether a visit is warranted. Sending an enquiry does not commit you to any work.
- No obligation
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