World Education

Home foundations aren’t all they are “cracked up” to be. A large majority of all homes built in the U.S. are going to experience some kind of foundation failure at some point. Even if it takes 30 years or more. These failures are seen in the form or either large wall cracks or large floor cracks. Hairline cracks are normal and are to be expected with all poured concrete foundations to a degree, but the larger cracks (greater than 1/8”) represent a major problem. Hairline cracks are either usually caused by the normal drying process of a freshly poured foundation due to shrinkage, or minor stresses placed on the foundation through different temperature changes over the lifetime of a foundation.

Now the larger cracks are always due to one of two reasons: settlement or hydrostatic pressure.

Settlement is characterized by large and sometimes heaving cracks on the surface of the foundation floor. The cause of this is the lack of soil material beneath the surface of the foundation, contraction of the soil material beneath the surface of the foundation, or both. Concrete is incredibly strong when it has a surface behind it to support it, but becomes very weak when that surface is no longer there. Concrete will crack under its own weight alone without a good back behind it. Driveways and sidewalks are a good representation of this.

Now, how does the surface beneath the foundation of a home get to be this way especially after a home has shown no signs of foundation failure for years, or even decades. A lot of the time there is poor drainage around the perimeter of a home’s foundation. With enough rain over a period of years, even a home with good drainage and especially ones without a sump pump will have soil eroded away beneath the footings of the foundation walls and concrete floors. When enough water has entered into the perimeter of the foundation, small amounts of soil can become displaced. Over a period of time, this can add up to a considerable amount of soil. When the dry and hot months come along, the soil all the way around a home will lose its moisture and contract. This causes the displaced areas beneath a foundation to contract as well. Once this happens, the foundation is at risk for failure, and most the time will fail. This will result in a nice crack on the foundation floor. At this point, a portion of the house is literally sinking. Aside from this, all soils will expand and contract with gain and loss of moisture content. Some more so than others. The home will move with this expansion and contraction. As long as the foundation has a good backing, it won’t fail. Now, throw a nice big pinoak tree into a yard near the foundation, and the risk for foundation failure increases even more. Because along with the contraction of soil during the hot dry months of summer, a tree will contribute to even more contraction due to the large amounts of moisture that it can pull away from a yard. Poor drainage and a large tree is an excellent recipe for foundation failure. Once settlement has occurred, very rarely does it never get any worse. A settled foundation usually tends to get worse and worse as the years go by to the point where there are large heaving cracks 1/2” and larger on the foundation floor which also results in stuck doors and drywall cracks throughout the main and upper levels of the home. Even worse, exterior materials of a home can become damaged or cracked. Especially brick or stucco. Roofs can develop leaks. And even windows can possible crack or break.

Now for wall cracks. The usual reason behind wall cracks is hydrostatic pressure. This is from large amounts of water entering the soil around the yard which causes the soil to expand. This places pressure on foundation walls. If a yard is always wet or receiving large amounts of rainfall every year, the the walls of a foundation will give in and crack and will typically bow inwards. Every time it rains or when snow melts, water will enter in through these cracks. Sometimes a crack in a wall can be the result of foundation settlement. When the floor of a foundation fails, and a portion of the home is sinking, this can place undo displaced stress on a foundation wall from the weight of the house. This can cause a wall to crack, and the crack will almost always be a horizontal crack. Although hydrostatic pressure can cause either both vertical or horizontal cracks. If you have a cracked wall, but absolutely no cracks at all on the floor of your basement, then it is more than likely a hydrostatic pressure issue.

What can be done about these foundation issues? Years ago, when something like this occurred, the homeowner was screwed. There wasn’t very much that could be done short of lifting the home and replacing the entire foundation of which had an enormous impractical price tag attached to it. Realtors would not deal with homes that had issues such as this.

Today, it is a different story. Although still pricey in most circumstances when dealing with settlement, a home’s foundation can be stabilized and in most cases lifted back to the original level that the sinking portion was at when the home was built. The way this is done is by digging holes along the perimeter of the foundation from the outside of the house all the way to the bottom of the foundation. Once the bottom is reached, one of several products available will be used to underpin the foundation of the home. The products are different variations of metal rods. These rods are driven into the earth with machinery all the way to bedrock. This can be as far as 20 – 30 feet down, or even further if need be. Once bedrock is hit, the steel rod has a solid foundation to rest on that will never move. The home is then lifted with hydraulic machinery to whatever level is satisfactory provided no damage occurs to the home when this is performed. Once that level is achieved, the rod is driven down to bedrock underneath the house and placed in such a way with other steel attachments for the home’s foundation to rest on. These rods can support 70,000 – 100,000 lbs. The number of rods used to underpin a home depends on the severity of the damage. The rods are place about 5 – 7 feet apart around the perimeter of the foundation that is failing. Typical costs of this ranges from $7000 - $15000. When it comes to wall cracks, usually a steel beam is placed against the wall, and then driven into the foundation floor from inside the home and attached to the ceiling joists in the basement. This keeps the wall stabilized. This cost is usually $700 - $1300 per beam.

Most companies also offer a lifetime guarantee for the foundation never to settle again. Today, that makes the foundation actually better than new. A person buying the home is getting a guarantee never to have to deal with foundation issues.

Categories: Homes and Real Estate