Random Cracking Cracks that radiate across a concrete surface are unsightly and unsettling. In time, water can enter a crack and freeze, which causes further damage and widens the rack.

Cracked Concrete

  • Problem

    Random Cracking Cracks that radiate across a concrete surface are unsightly and unsettling. In time, water can enter a crack and freeze, which causes further damage and widens the rack.

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    Random Cracking Cracks that radiate across a concrete surface are unsightly and unsettling. In time, water can enter a crack and freeze, which causes further damage and widens the rack.

    Harry Whitver

    Random Cracking Cracks that radiate across a concrete surface are unsightly and unsettling. In time, water can enter a crack and freeze, which causes further damage and widens the rack.

  • Solution

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    Fix It Cracks can be repaired with injected, two-part epoxy. Done right, this restores the concretes strength to original or better. Another option is to fill the crack with siliconized acrylic latex. This does nothing to restore strength, it is intended only to keep water and debris out. Bear in mind, neither of the above will correct a deeper structural problem. Also, its nearly impossible for a repaired crack to look like anything but what it is.

    Harry Whitver

    Fix It Cracks can be repaired with injected, two-part epoxy. Done right, this restores the concrete’s strength to original or better. Another option is to fill the crack with siliconized acrylic latex. This does nothing to restore strength, it is intended only to keep water and debris out. Bear in mind, neither of the above will correct a deeper structural problem. Also, it’s nearly impossible for a repaired crack to look like anything but what it is.

  • Solution

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    Avoid It The goal, since all concrete cracks, is to provide a planned place for that to happen, called a contraction joint. Parameters include: spacing of 8 feet or less in each 90-degree direction; create while the concrete is still greenwithin 12 hours of placement; depth of one-quarter to one-third the slabs depth. Three types include: saw cut; tooled joint; and proprietary joint strip. Adjustments, such as a low water/cement ratio, can be made to the concrete mix to limit shrinkage and, in turn, cracking.

    Harry Whitver

    Avoid It The goal, since all concrete cracks, is to provide a planned place for that to happen, called a contraction joint. Parameters include: spacing of 8 feet or less in each 90-degree direction; create while the concrete is still green—within 12 hours of placement; depth of one-quarter to one-third the slab’s depth. Three types include: saw cut; tooled joint; and proprietary joint strip. Adjustments, such as a low water/cement ratio, can be made to the concrete mix to limit shrinkage and, in turn, cracking.

All concrete cracks. Period. Some cracks you can see and some are so small they’re invisible to the naked eye. What most homeowners don’t know is that concrete is supposed to crack, and it’s not necessarily a harbinger of structural disaster.

Concrete is at its greatest volume the moment it hits the forms. From that time on it loses water, both to hydration (the chemical reaction between cement and water) and to evaporation.

Similar to a drying sponge, as the water leaves, the concrete shrinks. That shrinking causes internal tension stresses. Concrete, while excellent at handling compression, is not very good at resisting tension. The result: cracks. The trick is to plan for cracks so that when they occur they’re not ugly or structurally compromising.

Of course, sometimes cracked concrete does indicate a structural problem. In such cases the concrete on each side of the crack can wind up out of plane, causing a tripping hazard in a slab on grade. And when a crack opens up 1/8 inch or more there may be underlying trouble. If in doubt, call an engineer to help diagnose the problem.