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Wall, Ceiling and Settlement Cracks – not all their cracked up to be!

Have you noticed a crack in the brickwork of your house or on the ceiling of the lounge room? Is it serious or not? Here is some information on the types of cracks found around the house; which cracks may point to serious structural problems and which cracks are normal movement within a house. It is strongly recommended that you get a building inspection completed by a qualified building inspector to assess the cracks around your house or unit.

Cornice Cracks

Thin cracks along the wall just below the bottom of the cornice are usually settlement cracks as the house adjusts itself and can be easily repaired. Plaster shear, where there is a jagged crack below the cornice that travels down the wall, could be a more serious problem and should be checked by an authorised building inspector.

Cracks in Brick Walls

Cracks in brick walls, can appear as horizontal cracks along the mortar, as broken bricks or as a crack following the mortar line in a step pattern. These types of cracks normally appear because of thermal expansion and contraction, or from the reduction in moisture of the brickwork. They normally occur on large external walls that face the sun, usually north, northeast and northwest. Thermal damage can also cause the mortar to become brittle and leave gaps between the bricks. If there is a substantial leak through the roof, this can also cause damage to the brickwork near the top of the roofline. Cracks in brick walls could also be a sign of a more serious foundation problem and would need further investigation to diagnose.

Cracks in Ceilings and Walls

Temperature and moisture fluctuations can cause ceiling and wall cracks. The different building materials used in the house construction expand and contract as the temperature and moisture levels vary throughout the day and over time. This causes pressure on the materials and subsequently may cause them to crack. It could also be a result of faulty installation or the incorrect type of gyprock used.

Cracks seen in ceilings and walls could be due to excess moisture from above the ceiling or behind the wall, either from the other side of the gyprock, particularly if the other side is a bathroom or the roof. It could also have excessive weight from the structure above the ceiling and the gyprock cannot withstand this weight. If the cracks have water stains around them or the material is bowed, this should be checked out by an authorised building inspector.

A more serious ceiling crack around the load bearing walls could be the cause of poor foundations. When foundations are compromised, the load bearing walls cannot support the weight.

Settlement Cracks

Settlement occurs when parts of the house foundations fall below the level they were during the original construction. When settlement occurs in the form of settlement cracks, the cracks can be seen in the foundations, basement floors, external paths and in external walls.

Why do settlement cracks occur?

  • It could be because of moisture loss in the soil beneath the stumps or foundation, which cause them to shrink.
  • There could also be a large amount of organic material included in the soil under the house, so when it decays over time, the soil collapses to fill the space.
  • It could be a result of timber shrinkage, even with kiln-dried wood; there will still be more drying out of the timber over time.
  • There could be a possibility of timber compression from undetected termite activity.


We recommend all cracks in any house or unit be properly checked with a thorough building inspection by a qualified building inspector. Besafe Property Inspections conduct onsite house and unit inspections, complete with clear photos and a thorough written report for your reference. As qualified builders, we can also advise on the approximate cost to repair or rectify faults.


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