How To Prevent Concrete Cracks How To Prevent Concrete Cracks

Common and frequently used construction material, concrete can develop cracks that can damage the integrity of a structure or foundation. While there is no way to guarantee prevention of cracks entirely, here are a few tips on how to reduce the possibility of damage to the concrete.

Use the Proper Amount of Water

Different kinds of concrete require different amounts of water to help the concrete spread easily when poured. However, as the concrete dries and cures, it can have a tendency to crack if the water content is too high for the type of cement you are pouring. When the concrete is going through the curing and drying process, the water evaporates, which can make it vulnerable to damage.

Compact the Subgrade

Before pouring concrete, make sure that the subgrade has been thoroughly compacted. Homeowners and do-it-yourselfers can rent subgrade compacting equipment to prepare the area where a slab is going to be poured and forms set. If compacting is not performed, the ground underneath the slab can be subject to settling and shifting, which will result in concrete cracks.

Cut Control Joints

Control joints help the concrete as it cures and dries. Cut joints the depth of the thickness of the slab. Joints should be spaced at a distance of 3 times the thickness of the slab. For example, if the slab is 5 inches thick, then joints should be cut every 15 inches.

Cut joints within 6 to 12 hours of pouring the concrete slab.

Cure the Concrete Correctly

Curing concrete properly helps prevent cracks from forming over time. As the slab dries, it must retain enough moisture so that the drying process is slow and does not result in dramatic shrinking, which will cause cracks. '

The curing and hardening process occurs over the days and weeks after the slab has been poured. This provides the slab with strength and stability. Here are a few tips to assist with curing:

  • Allow the slab to remain damp by covering it with burlap, sand or canvas.
  • Approximately 12 hours after the slab has been poured and control joints have been cut, start to cover the slab with water, either by flooding or misting it.
  • Apply a chemical membrane to the completed slab.
  • Apply waterproof paper or plastic to the slab as soon as it becomes resistant to surface damage. Plastic may discolor the slab, so use paper if the appearance and color of the concrete are important.

Apply a Sealant

Once the concrete is cured and dried, apply a sealant to protect the slab from damaging cracks, stains and discoloration. Sealants are easy to apply in an afternoon and require making sure the slab is clean. Apply the sealant evenly across the surface and allow it to dry for a minimum of 24 hours.

While it is not possible to completely avoid concrete cracks, using care and practical common sense when laying the slab can eliminate many causes of cracks.

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