Cracks in concrete may be cause for concern depending on the type and location of the crack.  If the cracks are in control joints or are surface cracks, simply filling the crack with an appropriate filler will likely prevent further damage.  If the crack goes all the way through the slab (structural crack), there is not much that can be done to prevent the eventual decay of the affected areas.

Control joints are purposefully set into a concrete slab when it is first poured to provide a place for cracks to go when the slab moves in response to temperature changes and movement of the earth beneath it.  In other words, cracks are directed to the control joints so that they will crack in a straight line instead of randomly throughout the slab.  When cracks appear in the control joints, they can be filled with a sealant to prevent moisture intrusion.

Surface cracks are small fissures in the top layer of the concrete.  While they may seem minor at first, left unattended these cracks will widen, worsen, and will allow water to penetrate the surface slab.  In the winter, water in the slab will expand and contract as it goes through freeze and thaw cycles, eventually resulting in concrete surface failure.  Repairing surface cracks is a simple fix and most homeowners can do it themselves with appropriate concrete repair material.  Being proactive in properly repairing surface cracks adds to the slab’s longevity and minimizes future expensive concrete fixes.

Structural cracks run vertically through the entire slab and repairs can be expensive.  A mesh with an overlay may disguise and possibly add time to the life of the slab, however, there is no complete structural “fix” currently available on the market.  As time goes on, each slab piece will move independently of each other, and parts of the slab may break into more pieces until the concrete surface is no longer level.  At this point, the solution is to completely tear out the affected areas and pour a new concrete slab.