Repairing potential 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 and decide on the proper action for the repairs.
Foundation wall cracks that are less than .064” wide typically do not leak. Any crack repair performed on these cracks is cosmetic only. Larger foundation cracks or ruptures do need to be addressed. These cracks are signs that you have, or had, foundation movement.Each type of crack gives you a clue to what is happening with your foundation. Stair step cracks, cracks that follow the grout lines between blocks or bricks, generally indicate settlement. Cracks that are wider at the top also indicate settlement. Horizontal cracks generally indicate bowing or inward movement. Repairing cracks and patching cracks should not be confused. Patching a crack is merely Band-Aiding a possible problem. Crack repair is much more involved and require special training and specialized equipment. Before structural crack repairs are performed contact a professional engineer for guidance.
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 or Bowing Walls
A foundation wall that has tipped, bowed, or severely cracked requires substantial reinforcement to prevent further deterioration. Repairing basement walls from the inside is usually accomplished carbon-fiber mesh or wall anchors spaced 4-6 feet apart along the entire wall.
Carbon fiber wall repair involves placing vertical strips of high strength carbon fiber in a bed of an epoxy compound. These carbon fiber strips will strengthen the wall far beyond its original strength. While it will not straighten a wall, carbon fiber repair will greatly strengthen basement walls that have not bowed more than 2”.
Wall plate anchors also strengthen basement walls along with being able to straighten them. They consist of metal plates placed in your yard (installed by excavating), and metal wall plates on the inside of your foundation walls The plates are connected by steel rods that can be tightened to pull the wall back outward. Helical tieback anchors perform the same functions as wall plate anchors. Helical anchors have tremendous strength and require engineering calculations to install correctly. The largest difference between helical tieback and wall anchors is the amount of excavating required. Helical tiebacks require full excavation on the outside of the basement wall opposed to wall anchors that only requires spot excavation.
Foundations and Expansive Soils
If your house is out of level and there is no obvious reason, it may sit on soil that expands when damp and shrinks when dry. This so-called “expansive soil” 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. 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 beneath the slab is limited. The first remediation is to reduce moisture fluctuations of the soil around and under your home. Making sure soil slopes away from the house, and draining away all gutter and downspout water is necessary.