Concrete Repair in Wilmington, DE

Concrete repair matters in Wilmington because so much of the city's concrete is old. With a median home built in 1946 and more than 40 percent of homes built before 1940, many walks, steps, driveways and garage floors have been through decades of freeze-thaw cycles and road salt. Some of that concrete can be repaired for a fraction of the cost of new. Some of it is past saving. Our first job on a repair call is to tell you which is which, and why it failed.

Common problems and what causes them

• Scaling and spalling: the top surface flakes or pops off. Water soaks in, freezes and expands, and de-icing salt makes it worse. It is most common on concrete without air entrainment or that was over-finished.
• Settling: a slab sinks or tips because the soil underneath washed out or compressed. Downspouts, leaks and poor grading are the usual causes.
• Cracking: all concrete shrinks and cracks some. Cracks that widen, shift or have one side higher than the other point to movement underneath.
• Heaving: tree roots or frost push a slab up.
• Crumbling steps: corners and edges break off old steps where water and salt sit.

Repair options

Crack filling. Narrow cracks in sound concrete get cleaned and filled with a flexible sealant to keep water out. HomeGuide's resurfacing guide puts crack filling at about $0.50 to $3 per linear foot.

Leveling. A sunken slab that is still in one piece can be raised by pumping material underneath. Mudjacking uses a cement slurry and runs about $4 to $9 per square foot in HomeGuide's leveling guide. Polyjacking uses foam and runs about $8 to $25. Leveling lasts longest when the water problem that caused the settling is fixed too.

Resurfacing. A thin overlay on concrete that is structurally sound but scaled or worn gives it a new surface. HomeGuide lists resurfacing at about $3 to $7 per square foot.

Section replacement. When one or two slabs are broken, we cut them out at the joints and pour new sections that tie into the existing concrete.

Step repair. Broken edges and treads on sound steps can be patched or resurfaced. Steps that have pulled away from the house or are cracked through usually need to be rebuilt.

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When to replace instead

HomeGuide's leveling guide says replacement is usually the better long-term choice when cracks are wider than a quarter inch, when there is significant spalling or surface damage, or when the concrete is severely deteriorated. Overlays on top of failing concrete tend to crack and peel along with it. We will tell you straight when a repair would only last a winter or two.

Fixing the cause

A repair only holds if the reason for the damage is dealt with. That might mean extending a downspout, regrading soil so it slopes away from the slab, sealing joints so water stops getting underneath, or switching from rock salt to sand. We point out what we see during the estimate.

Keeping repaired concrete in shape

Seal the concrete every few years. Keep joints and cracks sealed. Avoid rock salt, and never use de-icers that contain ammonium nitrate or ammonium sulfate on concrete. Keep water from pooling at slab edges. These steps cost little and add years to concrete in a climate like Wilmington's.