What causes cracking to a home’s slab?

11th November 2021
What causes cracking to a home's slab?

Concrete slabs are essential for a home’s foundation, they provide a flat, even and supportive surface for the home to be built on. There are many types of slabs now including waffle, raft slabs and more.

Causes of slab cracks:

– Too much water in the concrete mix
– Too hot of weather while the concrete is drying
– Too much weight placed on the slab
– Roots of a large nearby tree can spread underneath the slab and cause it to crack from the pressure
– Cracks can occur if a tree dies or is removed near the home if the roots were under the slab as it causes movement and a change in moisture.
– Flooding can cause the soil to rapidly expand which places pressure on the slab
– Drought can cause the soil to shrink which affects the support for the slab
– The ground underneath the slab settling can also cause cracks, slabs built on top of dirt with high reactive clay levels are more likely to experience movement

Warning Signs:

Some warning signs of a foundation problem include:
– Visible cracks in the concrete slab
– Cracked/loose tiles
– Cracks in walls
– Doors/windows jamming
– A sagging ceiling
– Uneven or creaking floors

When should I be worried?

Small cracks and shrinkage in the slab are common while the ground settles and may not compromise the structural integrity of the home, however, it is often very difficult to determine how deep the cracks run without a proper inspection.

If the slab has many small cracks or cracks wider than a few millimetres, it’s best to request an inspection from a structural engineer. For extreme cases, it may be necessary to seek the advice of a geotechnical engineer, in order to determine the root cause.

If cracking occurs in your concrete slab, our experienced team can carry out an inspection and provide you with a report outlining the structural integrity of your slab, offering advice on remedial solutions where required.

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