Subsidence repair means two things in the right order: first the cause of the ground movement is found and dealt with, then the damage is repaired. For most houses that means fixing a leaking drain or managing a tree, giving the ground time to stabilise, then repairing cracks. Underpinning is only used when the cause cannot be removed or the foundation is too shallow for the ground. We carry out every repair to a chartered structural engineer's design.
What is subsidence, and why does the cause matter so much?
Subsidence is downward movement of the ground that supports a building's foundations. In the Liverpool City Region the usual culprits are the same as anywhere in the UK: shrinkable clay drying out in long dry spells or near thirsty trees and shrubs, and leaking drains or water mains softening clay or washing fine sandy soil away from under the footings. The RICS consumer guide cites Which? as saying tree roots cause about 70% of cases.
The reason the cause matters is simple. If a drain is still leaking under a bay window, filling the cracks or even underpinning one corner will not stop the problem from moving somewhere else. Remove the cause and many houses stop moving altogether. That is why our subsidence repair and underpinning in Liverpool always starts with diagnosis rather than a fixed price for concrete.
What are the signs of subsidence?
The RICS guide lists these as the common signs. None of them proves subsidence on its own, but together they are a reason to get advice:
- New or widening cracks in plaster or outside brickwork, especially near doors, windows and corners.
- Cracks that appear suddenly and are wider than 3 mm, which RICS says are the main cause for concern.
- Doors and windows that start sticking for no obvious reason.
- Wallpaper rippling or tearing at the joints where walls meet ceilings.
- A solid floor that has started to slope.
Cracks that are wider at the top than the bottom, or that run down through the damp-proof course into the masonry below ground, are often linked to foundation movement. A structural engineer still has to inspect before anyone can say what is going on in your house. Our subsidence and cracks guide explains the crack categories and what each usually means.
How do we approach a subsidence repair?
- Talk it through. We call back and ask where the cracks are, how wide they are, whether they are new or growing, the age and type of house, nearby trees, drains, bays or extensions, and whether an insurer, buyer or neighbour is involved.
- Look at the property. We visit to see the damage. Where the cause is not clear we recommend a structural engineer's inspection before any repair is chosen.
- Investigate if needed. That may mean a CCTV drain survey, trial pits to expose the footing, soil tests or a period of crack and level monitoring, often around 12 months to separate seasonal movement from progressive movement.
- Deal with the cause. Drain repairs, or tree management guided by an arboriculturist and the engineer. Felling a large tree on clay can cause heave, so this is never done on a hunch.
- Repair to the engineer's design. Crack stitching, rebuilding damaged sections, replacing lintels or, where the engineer specifies it, underpinning. We give a written quote for the designed scheme and handle Building Control notices.
- Sign-off. The engineer and Building Control sign off the work as applicable, and you keep the paperwork for future buyers and insurers.
Which repairs might the engineer specify?
| Situation found | Typical repair route |
|---|---|
| Leaking drain softening or washing out the ground | Drain repair or relining, a period for the ground to stabilise, then drainage-related subsidence repairs to the masonry |
| Clay shrinkage linked to a nearby tree | Tree management on specialist advice, monitoring, then crack repair; underpinning only if movement continues |
| Movement has stopped, cracks remain | Structural crack repair, stitching and making good |
| Cause cannot be removed, or footing too shallow for the ground | Underpinning designed by the engineer: mass concrete, mini-piled, beam and base or resin, depending on depth and ground |
If you suspect subsidence, contact your buildings insurer first. The insurer decides on investigation, monitoring and the repair method, and whether underpinning is needed at all. We never promise a claim will be accepted. Our subsidence insurance claims page explains how the process usually runs.
Which Liverpool homes do we usually get calls about?
Calls tend to follow the housing rather than any one postcode. Victorian, Edwardian and inter-war homes with bay windows often have shallower footings under the bay than under the main walls, which is why bays are such a common place for cracking. Mature street trees and garden trees near older houses in suburbs like Allerton and Mossley Hill are a frequent topic, as are extensions built on different foundations from the main house. On the Sefton coast around Crosby the conversation more often turns to sandy ground and old drains. In general terms, parts of Merseyside sit on glacial clay, coastal areas have sandy ground, and backfilled former clay pits and poorly compacted made ground can be compressible. Nobody should assume what is under a particular house without investigation.
What can you do while you wait for advice?
Photograph each crack with a ruler or coin beside it and write the date on the photo. Note any door or window that starts to stick, and when. Keep gutters and gullies running freely. Do not start building work, tree work or digging near the walls, and do not fill and paint cracks to hide them, because the engineer needs to see how they behave. If cracks are opening quickly, a wall leans noticeably or a ceiling or doorway looks unsafe, keep people away from that area and get urgent professional advice; the council's building control team can deal with dangerous structures. If movement has damaged a gas pipe and you smell gas, leave and call the National Gas Emergency Service on 0800 111 999.
What affects the cost of a subsidence repair?
We do not quote a figure until the cause is known and the engineer has designed the repair. The main factors are the investigation needed, whether drains or trees have to be dealt with, the method and depth of any underpinning, the length of wall, access, Building Control and party wall involvement, and internal making-good. Our underpinning cost guide sets out published national figures and what pushes a job up or down.
Worried your house is moving?
Call 07777 659786 or send your details using the form. Tell us what you have noticed and whether an insurer is involved, and we will call you back to talk through sensible next steps for foundation and subsidence problems on Merseyside.
Frequently asked questions
Does subsidence always mean my house needs underpinning?
No. The RICS consumer guide on subsidence says fewer than 5% of affected properties require underpinning, and the Institution of Structural Engineers recommends it only as a last resort. Most homes are put right by finding and removing the cause, such as a leaking drain or a thirsty tree, letting the ground settle down, then repairing the cracks.
Should I contact my insurer before calling a contractor?
Yes. If you think the house may be subsiding, tell your buildings insurer first. The insurer and its loss adjuster or engineer decide on investigation, monitoring, how the cause is dealt with and which repair is used. We can explain the process and carry out a scheme once it is agreed, but the insurer makes those decisions.
Is it subsidence, settlement or heave?
Subsidence is the ground beneath the foundations moving down. Settlement is a building compressing the ground under its own weight, usually early in its life, and it normally stops. Heave is the ground moving up, often when clay swells. They can produce similar cracks, so a structural engineer needs to look before anyone can say which it is.
How long does a subsidence repair take?
It depends on the property, the cause and the permissions needed. Investigation and monitoring can take months before any repair starts. Crack repairs after the cause is removed may take days; if underpinning is needed, MyJobQuote says most jobs take about 3 to 5 weeks on site, with approvals and party wall matters sometimes adding months beforehand.
Can I sell a house that has had subsidence?
Many houses with past subsidence are sold. Buyers' solicitors commonly ask for the repair history, any Building Control completion and, after an insurance repair, the certificate of structural adequacy that the insurer's engineer often provides. Never hide past movement from a buyer, lender or insurer; being open with the paperwork is what makes a sale workable.