Worth knowing / How it works
How heritage subsidence repair works
Heritage buildings move differently from modern ones, and the repair approach has to match the fabric. These steps cover what happens from the moment you describe the problem to the point the specialist hands over completed work and all supporting documents.
Whether the job calls for crack monitoring, underpinning or lime mortar repointing, the stages below apply to every heritage subsidence repair.
Describe the damage you have found
Use the form to give the property address and a short account of what you have noticed: diagonal cracks above window openings, stepped cracking in lime-jointed brickwork, a floor that has dropped toward one corner, or a door that has started to bind. Note which direction the cracking runs, roughly how wide the gaps are, and when you first saw them. Say whether the problem looks the same now or has changed. Placing a coin or pen next to the crack before photographing it helps the specialist read the size of the damage. There is no charge for the quote.
A specialist phones you
A heritage subsidence specialist will call you to go through what you have noticed and gather the details they need. They will want to know the age and construction of the building, the soil type beneath it if you are aware of it, whether large trees are nearby, and whether any drains or gutters have been leaking close to the affected wall. Tell the specialist at this stage if an insurer has already opened a claim.
Working out whether a site visit is needed
Using what you have described, the specialist decides whether a visit to the property would add useful information. If the movement appears ongoing, crack monitors can be fitted to record readings across several weeks. Those readings show whether the structure continues to move, whether clay shrinkage driven by seasonal change is responsible, or whether the building has settled into a stable state. That information determines which repair method is appropriate for the age and construction of the building.
A written quote provided at no cost
Once the specialist has enough information, they set out the probable cause in writing and price the repair that addresses it. For a heritage building, that might mean lime mortar repointing, structural underpinning to reach a stable bearing layer, load-bearing wall stabilisation, crack stitching, drainage investigation to find a leaking pipe, or removing a nearby tree whose roots are drawing moisture from shrinkable clay. The quote is free.
The repair work
The specialist firm confirms access arrangements, explains which parts of the building and the surrounding ground will be disturbed, and agrees a programme before any work begins. Materials and methods are chosen to suit the original fabric: lime-based products are used where the existing construction requires them. Work covers only what the site evidence supports.
Documentation and handover
Once the repair is complete, the specialist draws up a written account of the findings, the treatment applied, and the state of the structure at sign-off. Keep any certificate the specialist issues alongside your title deeds. Insurers, mortgage lenders and solicitors acting for buyers request documentation of previous ground movement, and a heritage building with a well-documented repair history is considerably simpler to deal with.
What you get
A written quote stating what the specialist believes caused the movement and which repair they recommend
Where crack monitors were installed during the investigation, a record of the readings collected
A written summary from the specialist detailing every element of the work performed
Any certificate the specialist produces once the repair is complete
Before the visit
Photographs of affected masonry and wall faces
Approximate date the movement or cracking was first observed
Buildings insurance schedule and any claim correspondence
Earlier structural or ground investigation reports
Positions of substantial trees or shrubs near the building
Before you ask
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What is subsidence and what causes it?
Subsidence occurs when the ground under a building's foundations drops or shifts downward. Shrinkable clay soils drying out in hot summers, tree roots drawing moisture from the soil, and leaking drains washing material away from beneath footings are common triggers across the UK. When the ground shifts unevenly, walls crack, frames go out of square, and floors can slope. Left without attention, the movement and damage tend to worsen.
What do subsidence cracks look like?
Diagonal cracks running from the corners of windows or doors are a recognised pattern, particularly where the crack is wider at one end. Stepped cracking along mortar beds in brickwork, gaps opening between walls and ceilings, and doors or windows that suddenly stick can all point to foundation movement. A specialist can examine the pattern and width of cracks to determine whether active ground movement is the cause.
What does a subsidence survey involve for a heritage building?
A specialist will attend the property, record crack patterns and widths, examine the foundations, check drainage, and identify the likely cause of movement. Heritage buildings often require lime-based repair methods rather than cement, and the specialist takes the construction type into account before advising on next steps. After the assessment, the specialist provides a written summary of the repair options available.
Can subsidence in an older building be put right without underpinning?
Sometimes. Where a leaking drain or tree roots are causing the ground to move, addressing those problems may be enough to stop further settlement. Crack monitoring over a period of time can then confirm whether the ground has stabilised. Structural underpinning is reserved for cases where the foundation itself cannot carry the building once the underlying cause is removed. A specialist assesses which approach suits the property.