Foundation Repair Companies
A foundation’s main job is to hold up the house. Often, however, the biggest load on the foundation is not the weight of the house, but the pressure of the soil around the foundation.
Most clients have no knowledge about their foundation and its condition until they begin to notice problems inside their homes- generally settlement cracks, sticking doors and sloping floors are indicators that something is amiss.
Though there is no cut and dry formula to show when a foundation needs to be replaced, there are a number of indicators which when looked at together should point the direction one way or another.
Do I Need a New Foundation?
1. Are there drainage issues?
Drainage is the #1 culprit, and leads to settlement, cracking, and deterioration of concrete. Older concrete is somewhat porous, and water will soak into the material causing it to deteriorate. Since most older homes have nonexistent or improperly installed drainage systems, it is important to have the drainage issues addressed- either as part of the foundation work, or if the foundation is in decent condition to avoid an expensive foundation replacement project in the short term.
2. Is the concrete deteriorating?
By poking around with a screwdriver, we can see how intact the concrete is. Often concrete with lots of sand in the mix that has been subjected to drainage issues will be so soft it can be pulled apart with your fingers. This condition can be of major concern, as this concrete has very little strength and could liquefy in an earthquake. The harder the material the better. Appearances can be deceiving. Some of the ugliest concrete with lots of rocks and voids can be quite strong and is less of a concern.
3. Are there cracks?
A few cracks in older foundations is expected, but lots of cracks, especially one’s that are ¼” or larger can be problematic. Since older foundations typically do not have rebar in them, once large cracks occur the concrete can separate into sections that can rotate or settle independently from one another, causing settlement or shifting in the house above.
4. Is there rebar?
Most homes built before 1930 or so do not have steel reinforcement in them. Rebar helps to strengthen the concrete and hold it together in the event of cracking from settlement or earthquakes- cracks can still develop, but they remain hairline and don’t pull apart. The modern foundations we build have at least 5 pieces of rebar running horizontally, and verticals every 12” so they are heavily reinforced.
5. Depth and location of the concrete.
Often older foundations are not of sufficient dimensions to work effectively. If the footings are not at least a foot or more below the grade level they will be subject more to movement in expansive soils and drainage issues. If they are not 6” or more above grade there can be water issues at the framing level causing dry rot issues above. And if the soil is excavated on the interior of the basement or crawlspace too close to the foundations or if the footings are functioning as retaining walls and they are not designed properly they may settle or move, and they may create drainage issues leading to more settlement.
Soils are mixtures of mineral particles, water, and air. They’re not quite solid and not quite liquid, but they can flow. The more water a soil contains, the more it behaves like a fluid. As water lubricates the small soil particles, they slip more easily past each other.
Clays are particularly affected by moisture: A clay embankment that stands up by itself when dry may turn to mud and slump like pudding when wet. That’s why effective drainage systems are a critical element when building in clay soils.
Groundwater exerts its own pressure on basement walls as it seeps through the earth. The water pressure against a basement when the soil is thoroughly soaked is called hydrostatic pressure. It can force moisture through pores in the basement wall and even crack or buckle the wall itself. Here again, proper drainage is the remedy.
Digging Deeper Increases Pressure
Hydrostatic pressure and soil pressure increase with depth. Just as a submarine experiences more stress on the hull as it dives deeper, a basement wall faces more lateral pressure deep underground than it does near the surface. Other things being equal, deep foundation walls need more strength than shallow ones.
Horizontal, open cracks are typically a sign that your basement wall is beginning to push in or even buckle. Horizontal cracks are often caused by frost heave (expansion of water when it freezes) against the wall or heavy wet soil from hydrostatic pressure. These types of cracks may denote a structural issue and should be addressed immediately.
Vertical cracks in poured concrete walls may be a result of settling. These types of cracks often occur inside the corner of a window opening or beam pocket. Vertical cracks in block basement walls is often a sign of blunt trauma to the outside wall often done during the back fill process.
Step cracks usually appear from minor settling in block basements. Fine step cracks in isolated areas are usually not structural. These may require minor repair to prevent moisture from leeching into your basement.
Open step cracks are more of a concern. This means that more substantial settling has taken place. If you see dirt, mud, sediment or stains on the wall or floors around the cracks, this means the soil outside is pushing through the cracks. This should be addressed immediately.
Bowed or bulging basement walls means your wall is buckling from the pressure exerted on it by the outside dirt and water. If this is not treated, eventually your basement wall may collapse and further damage may be caused.
A bowed wall typically can be repaired using structural support and wall bracing. It is also imperative to reduce the pressure on the outside wall. This typically requires the replacement of the exterior drainage system to reduce the soil moisture and hydrostatic pressure being exerted on the wall.
Cracked basement floors, where part of the slab appears lower than the rest, is a sign of floor settling. Large open cracks in the floors are gateways for water and insects to infiltrate your home and should be addressed.