Cracks on a concrete slab are quite common, and only a few actually pose a threat to the structural integrity of your slab.
Common types of cracking in concrete slabs
Plastic shrinkage cracking:
Before concrete hardens and is still full of water it is in its plastic state. Once the water in the slab has dried it leaves behind empty spaces, which then make the concrete weaker and more susceptible to cracking. This type of cracking is common, being referred to as “plastic shrinkage cracking”.
Expansion concrete cracks:
Expansion cracks occur when concrete expands due to a change in heat. This expansion causes the concrete to push against anything in its way, like a wall, or an adjacent slab.
Heaving concrete cracks:
Comparatively, if the ground becomes freezing it can sometimes cause the concrete to lift inches before the ground eventually cools down. If a slab does not have room to move it will crack.
Large tree roots can also cause heaving concrete cracks. If a slab and a tree are too close together the roots of the tree can cause the concrete slab to rise. If you are unsure of the level of volatility a crack has on your concrete slab’s stability, Bayside lifestyles building inspectors in Brisbane can help.
Concrete cracks caused by overloading the slab:
While concrete is a strong building material, it has its limits. When too much weight is applied to a slab cracking will occur, especially if it is applied after heavy rain when the ground underneath is soft and wet. Residential homeowners who place large recreational vehicles or dumpsters on their driveways are particularly suspectable to this type of cracking.
When to be concerned
If there are cracks that appear on any form of vertical concrete like a wall or fence, this is when there is cause for concern. This suggests that there is some settling happening, which is caused by the ground the concrete slab is situated on having a void or hole and is no longer able to hold its weight. For example, if pipes or a large tree that are situated near or under the concrete slab are removed it creates a void, causing cracks.
To an untrained eye, it can be difficult to judge whether a crack in a slab poses a concern or is simply just general wear and tear. Having a professional building inspector in Brisbane conduct this exam for you is a smart way to ensure the safety and structural integrity of your concrete slab.