Finding a crack in a wall can be worrying, particularly when you are buying a property or have been told that a lender or insurer is concerned about movement. The important point is that not every crack is structural and not every structural crack means subsidence.
A structural engineer looks at the pattern, location, construction and history of the defect rather than judging a property from one crack in isolation.
Cracks that deserve closer investigation
- Stepped cracks through brickwork or masonry.
- Diagonal cracks extending from window or door openings.
- Cracks that are widening or repeatedly reappearing after repair.
- Cracking accompanied by distorted openings, sticking doors or windows, or uneven floors.
- Separation between an extension and the original building.
- Bowing or movement of walls, ceilings or other structural elements.
What can cause cracking?
Possible causes include normal shrinkage, thermal movement, settlement, differential foundation movement, nearby trees, leaking drains, inadequate lintels, roof movement, corrosion, timber defects and alterations to the structure. The correct remedy depends on the cause.
Does a crack mean subsidence?
No. Subsidence is one possible cause of movement, but cracking can arise for many other reasons. In London, shrinkable clay soils, vegetation and drainage can be relevant, but an engineer should consider the full evidence before attributing a defect to subsidence.
What does a structural inspection involve?
The engineer will normally inspect the relevant areas, record the crack pattern and surrounding construction, consider accessible evidence of movement, and assess likely causes. Where a visual inspection cannot establish whether movement is ongoing, further investigation or monitoring may be recommended.
If you are buying a property
If a surveyor or mortgage valuer has flagged cracking, obtain the valuation wording before arranging the engineer's inspection. This helps ensure the inspection addresses the actual concern rather than producing a generic report.
Laytoe Structures provides targeted structural inspections and broader structural surveys for residential properties across London, including investigations of cracks, movement and suspected subsidence.
If you would like an engineer to look at your property, see our structural inspection service in London. Inspections start from £420* with a written quotation before we visit, or call 020 3983 5057.