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What You Need to Know About Foundation Repairs

By Jeanne Huber

Foundation repairs run the gamut from simple DIY fixes to major reconstruction. Here's what you need to know about your options, and when to call in a pro.

Fixing foundation problems should be a priority for every homeowner. Foundation repairs prevent little problems from becoming bigger, keep your home safe, and protect the value of your property. Fortunately, foundation problems tend to develop and worsen slowly, giving you time to make a thorough evaluation (http://www.houselogic.com/articles/understanding-foundation-problems/) and decide on the proper course for repairs.

Narrow cracks

Cracks less than 1/4-inch wide require the easiest foundation repairs, especially if they're located where concrete tends to crack naturally from shrinking as it cures. You can probably leave these cracks as-is. But if water is seeping through (http://www.houselogic.com/articles/7-signs-you-may-have-a-drainage-problem/) or you'd like to seal cracks for cosmetic reasons, apply a good-quality, paintable silicone caulk or epoxy putty.

Wide cracks

Horizontal cracks, vertical cracks wider than ¼-inch, or stairstep cracks in blocks or bricks tip you to more serious problems. You can hire a contractor to plug deep cracks by injecting epoxy ($1,500-$3,000), or do it yourself with epoxy putty, but either way, you'll only be stopping water from coming in.

Patching cracks won't make your house level again or stop whatever forces caused the cracks in the first place. "Patching cracks is like putting on a Band-Aid," says Jim Hise, owner of Expert Basement Repair in Cleveland. To heal the wound, you need to fix the underlying problem.

Basic foundation repairs

A common culprit is water accumulation in the soil around the foundation, which expands the soil and puts pressure on walls and foundation footings, causing cracks to appear. Check to make sure all gutters and downspout drains are in good working order, and that the soil around your foundation is properly graded-it should slope at least 6 inches for every 10 horizontal feet.

Most foundations are required to have a perimeter drain system that channels sub-surface water away from the foundation. The drain system is made of concrete tiles or perforated plastic pipe buried in a gravel bed. It usually drains externally (a pipe that opens onto a low spot in your yard), or connects to your sewer system.

It's possible for this drain to become blocked, causing water to accumulate in the soil and putting pressure on your foundation walls. If you suspect a blocked perimeter foundation drain, seek the advice of a licensed foundation contractor.

Buckled wall and severe cracks

A perimeter foundation that has tipped, bowed, or severely cracked requires substantial reinforcement to prevent further deterioration. Repair the walls from the inside with wood or steel braces, carbon-fiber mesh, or wall anchors spaced 6 feet or so apart along the entire wall.

For about $500 to $700 each, wood and steel braces install against the wall and attach to the floor and overhead joists, blocking further movement. However, they intrude into the basement area about 6 inches, making it difficult to finish the walls. A newer option, which costs less than half as much and winds up almost invisible, involves spreading epoxy in vertical strips and then pressing on carbon-fiber mesh to lock the wall in place.

Wall anchors are similar to large bolts. They consist of metal plates in your yard (installed by excavating), and metal plates on the inside of your foundation walls The plates are connected by steel rods buried horizontally. The connectors are gradually tightened to stabilize and help straighten the wall. Wall anchors are placed every 6-8 feet, and cost $400-$600 each.

If a foundation wall bows severely (more than 3 inches) or if you want to make it straight again, you probably won't be able to fix the problem from the inside. You may need to excavate part or all of the foundation and rebuild it-a $30,000 to $40,000 job.

Washed-out areas

If a broken water pipe, a plugged gutter, or a drainage problem in your yard sent enough water cascading alongside a perimeter foundation to undermine an area, a contractor might be able to shore up the area with more concrete or shim the sill plate to make the area level again. Or you might need to tear out a section of the foundation, repour, and tie the new section into the old with rebar and epoxy.

Simple fixes with concrete and lumber might cost as little as $500 or as much as several thousand dollars. Just be sure that the underlying cause is fixed first, or the repair won't last.

Foundations and expansive soils

If your house is out of kilter and there is no obvious reason, it may sit on soil that expands when damp and shrinks when dry. This so-called "expansive soil (http://geology.com/articles/expansive-soil.shtml)" is found in all states and has damaged about a quarter of all houses in the U.S., according to the American Society of Civil Engineers (http://www.asce.org/). If you suspect you have the problem, check with your local building authority to see if expansive soils exist in your area.

Dealing with this kind of soil is most difficult if you have a slab foundation because access is to underneath the slab is limited. First, try to reduce moisture fluctuations under your house. Make sure soil slopes away from the house, and pipe away all gutter water. Replace water-thirsty landscaping within 5 feet of the walls with plants that need little water or, even better, install a concrete path around the house so rainwater can't soak in there.

If you live in a damp climate and notice settling issues such as sticky doors during droughts, try the opposite approach. Keep the soil evenly moist by running drip irrigation around the perimeter during dry spells. If you see cracks in the soil, it's too dry. But don't dump water into a crack; irrigate a foot or two away from the foundation, and use an automatic timer so you add a little water several times a day rather than a lot all at once.

A contractor may be able to raise a sunken area in the middle of a room by "mud-jacking," or pumping a cement slurry under the slab under pressure. Mud-jacking can't raise load-bearing walls, however. For that, you need to support the slab with underpinning that reaches down to a more stable layer, a fix that costs $5,000 to tens of thousands of dollars.

Options for underpinning include steel posts driven in hydraulically, and helical piers, which have blades that screw into the soil. Installation costs $1,200-$1,500 per pier, with one every 6 to 8 feet. Another option consists of pre-cast concrete pieces about 1 foot high that are pressed down on top of each other by the weight of the house, creating columns underneath.

Contractors tend to specialize in a single solution and often are quick to point out problems of other systems. That's why it is so helpful to have a structural engineer's guidance. In truth, the best option varies according to the circumstances.

Working with a structural engineer

Trustworthy advice comes from a structural engineer. An initial visit (about $500) should reveal the severity of your problem and tell you what to do next. If you need a full engineering report, expect to pay several thousand dollars. You might also need a soils engineer and core samples, doubling the cost.

In the end, you should get a written report that makes specific recommendations and lays out pros and cons of each option. If you need a complicated fix, you might want to hire the engineer by the hour ($100-$200) to inspect while work is underway.

Free estimates from foundation-repair contractors make sense if you live in a neighborhood where one solution has succeeded in similar homes. "Get two or three bids and see if you get a similar pattern of suggestions," recommends Richard Morant, operations manager of Dawson Foundation Repair in Dallas. If the advice isn't consistent, call a structural engineer with no vested interest in a specific solution.

Jeanne Huber is a free-lance writer who has specialized in home-repair issues for about 15 years. She writes a weekly column for the Washington Post and is a former editor at This Old House.

Jesse Samples and Sarah Samples at Allen Tate Realtors in Charlotte, NC

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