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Need Foundation Repair?

The Foundation of your house fails, starting outside in the soil...

The job of the foundation is to hold the house up. Although, the main load on the foundation is the pressure of the soil around the foundation not the weight of the house. This is known as the lateral load, it's the amount of pressure on  basement walls. There are many elements to consider, including but not limited to, the soil type that's outside the foundation, the amount of water in the soil and depth of the foundation beneath the ground surface.

Coarse-grained, well-drained soils like sand and gravel apply the least lateral load, while fine silts and clays, especially if saturated, apply more load. The deeper the basement, the greater the pressure. The designer and builder must understand the importance of these factors in order to design and build a foundation that can stand up to lateral loads. Since soil engineering is not an exact science and loads are hard to predict accurately, all foundations should have a large, built-in margin of safety.

How Water Effects the soil

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 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.