If major cracks appear on a wall, it could be a sign of subsidence
All buildings are subject to fractional but constant movement: bricks, timber and concrete will expand and contract based upon changing environmental conditions over monthly and seasonal cycles. Normally, a building’s superstructure can comfortably accommodate this, but more acute movement may lead to evidential cracks in walls, floors and ceilings.
These are normally categorised as either a failure in the initial design, building settlement or subsidence.