Cracks in walls of a property can be concerning for both seller and buyer. The cost of repairing wall cracks alone can be considerable, but a crack can also point to bigger, underlying structural issues that will significantly affect the property’s value. To figure out what kind of repair you’ll need – and how costly it will be – here are some expert tips from our building inspectors about cracks in walls: when to worry, how to identify the type of crack, and when it’s time to call the professionals.

Types of wall cracks

Cracks in walls are usually categorised by their location, and there are three types.

  • Exterior wall cracks, occurring in brickwork, surface or rendering of external building walls
  • Interior wall cracks, occurring in the plasterboard or gyprock of inside walls
  • Foundation wall cracks, occurring in a building’s foundation walls, usually made of concrete blocks

Each of these types of wall cracks can be very serious or fairly harmless, depending on the size, location and cause.

What can cause cracks in walls?

Cracks in walls can be caused by:

  • Settling and subsidence of the building
  • Climate change and the weather patterns that cause significant soil contraction or expansion
  • Poor design or construction, for example, faulty building materials, inadequate reinforcement 
  • Water damage, such as blocked gudders, leaking pipes or flooding
  • Invasive trees, whether from roots, moisture retention in soil or destabilisation during the removal of a tree
  • Excavation work in the area

Cracks in walls: when to worry

cracks in walls when to worry how to repair

While simple fillers and a coat of paint can fix shallow, superficial cracks, larger, deeper cracks require immediate attention and action.

Indications that you need to worry about that crack in the wall include the direction, cause and location of the crack.

Based on direction

  • If the crack is vertical, it’s likely caused by foundation settling and not as severe as other types of cracks.
  • Horizontal cracks in walls are often more severe, as they are usually caused by water damage, shifting foundations or structural issues.
  • Diagonal cracks can be expensive to repair because they indicate subsidence of footings.

Based on location

A wall crack is more serious if:

  • the crack occurs where the wall meets the ceiling,
  • nails or screws have started to protrude and are visible on the surface, since nail popping can indicate foundation damage or issues with structure or construction
  • warping, bowing or leaning of walls is also present. These are warning signs of imminent collapse and must be dealt with immediately to ensure the building is safe

Depending on the severity of cracks in walls, repair options may include excavating foundations to lay new concrete, replacing damaged foundation stumps, stabilising the footings, or in the worst cases, demolition and reconstruction.

If you’re buying or selling a house, you’ll need a professional building inspector to identify what caused the crack, how serious it is, and what kind of repair you’ll need to ensure it’s valued accurately and passes an inspection.

Contact us to book your inspection and we’ll help you figure out when to worry about that wall crack!