Cracks in Brickwork

Your building inspection may report on cracking to brickwork. It is important to know that minor cracking is common and generally will require cosmetic or basic repairs only. Finding cracks in your brickwork does not necessarily mean that your house is going to fall over. The first thing to understand is that all buildings move due to expansion and contraction as well as wind loads and other forces that occur naturally to the building.

Older buildings may not have been constructed with expansion or construction joints which are now mandatory for most masonry construction. These joints allow for more predicable movement in the building, therefore reducing the occurrence of cracking. It is not necessarily a cure all component.

Most people do not realise that the most important element of the total building structure is what it is sitting on, the foundations.  Many misinterpret the foundations as the base structure, like, the base brickwork, slab or stumps; these are what are known as footings. The foundation is the soil that the building sits on.  

Soil conditions can be problematic

Before any building is built these days, two very important issues are dealt with prior to any commencement of construction, they are a soil report and the engineer’s computations for the design of the foundational structures, the footings or slab design. The soil report is crucial as this will inform the engineer as to the makeup of the sites soil.

There are a variety of soil classifications, but they basically boil down to a variation of ‘Non-Reactive’ and ‘Reactive’. Reactive soils will usually have high clay content where the clay reacts, expanding and contracting to differing moisture conditions. Depending on where the building is situated and the climate situation soils will react to cyclical periods of wet seasons and dry seasons. Drought conditions will invariably cause shrinkage of clays. It is common for home owners to notice sudden cracking in their homes during prolonged drought conditions. There are other factors to also consider if your building inspection has uncovered cracks.

Trees can be problematic

It is common for people to equate tree roots as the cause of cracking in brickwork where they mistakenly believe that the roots have uplifted the foundational structures. This can be true in some cases, however, it is more likely that the tree roots have caused cracking because they extract large amounts of moisture from the founding soils thus upsetting the equilibrium of the soil. Trees can extract up to 300 litres of moisture a day. Many houses have large or even smaller trees planted far too close to the building.

Steel lintels can be problematic

Steel lintels and steel arch bars that support brickwork can often rust and corrode. Once corrosion has occurred the steel can expand significantly and cause uplifting of overhead brickwork. Replacement of affected lintels is usually required. If your building inspection has identified cracks in brickwork and whether they are minor or significant cracks, the most prudent thing to do is engage the services of a Geo-Technical Engineer and/or Structural Engineer. The engineer will take into account a variety of considerations most important being a soil report.

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