A crack in the wall is enough to make any homeowner’s heart sink. But not every crack means subsidence, and knowing the difference between harmless settlement and genuine structural movement can save you both needless worry and, occasionally, a serious problem left too long. Here is how to read the signs.
Settlement vs subsidence
Almost every building moves a little. New buildings settle as they bed in, and old buildings shift gently with the seasons. This normal movement produces fine, stable cracks that do not worsen — nothing to lose sleep over. Subsidence is different: it is the downward movement of the ground beneath the foundations, which pulls part of the building down with it. That is structural, and it needs attention.
The warning signs
The cracks that suggest subsidence rather than harmless settlement tend to share certain features. They are often diagonal, running at an angle rather than straight. They are usually wider at one end than the other — tapering. They tend to be wider than a typical settlement crack, often more than a few millimetres. They frequently appear near windows and doors, where the structure is weakest, and may show both inside and outside on the same line. Doors and windows that suddenly stick, or rippling wallpaper over a crack, can accompany them.
A single hairline crack is usually nothing. Several tapering diagonal cracks appearing or widening, especially around openings, deserve investigation.
What causes it
Subsidence has various causes: clay soils shrinking in dry weather, tree roots drawing moisture from the ground near the building, leaking drains washing away or softening the soil, and previous ground disturbance. Identifying the cause is central to knowing how serious it is and how to address it.
When to get a survey
If you are seeing the warning signs — tapering diagonal cracks, movement around openings, cracks that seem to be growing — it is worth having a building survey to assess what is happening. A building surveyor can distinguish genuine structural movement from harmless cracking, identify the likely cause, and advise on whether monitoring, further investigation or remedial work is needed. Catching real movement early gives the best chance of a straightforward fix; ignoring it lets a manageable problem grow.
Buying a property with cracks
If you are buying a home and spot concerning cracks, do not simply take fright or take a chance — get it assessed. A survey tells you whether those cracks are cosmetic or structural, which is exactly the information you need before committing.
At Emerald Ritter we survey properties for signs of structural movement across the region, giving you a clear, expert assessment of what is really going on. If cracks are worrying you, get them properly looked at.
