Foundation Repair For Builders: Why Soil Matters
Builders put a lot of thought into whether or not the foundations they lay will be strong enough to support the house they build on top of it, and rightfully so. Yet there’s more to ensuring a strong foundation than the construction of the foundation itself. For example, when building a home with a pier and footing foundation or a step footing foundation, it’s also important to consider the soil condition throughout the entire footprint of the foundation. If the builder doesn’t take the time to understand and adjust for the condition of the soils underneath the footing foundation, it can lead to some serious problems for the homeowner over time. To avoid costly foundation repair in the future, it’s essential to pay attention to the soil beneath your foundation before you build it.
Why Soil Is Important For Foundations
Typical soils can support a standard house foundation footing with no trouble. However, there are some instances in which the soil condition around a property isn’t consistent — and that’s where trouble begins to brew. For example, if the soil underneath one footing is softer than the soil under the other footings, the section of the house above that footing may settle faster and deeper than the other portions of the house — leading to the need for potentially serious foundation crack repair.
The quality of the soil directly underneath each footing is extremely important. Because, the soil pressure is at its greatest for a depth about equal to the width of the footing. For example, a typical 16-inch footing means the soil-bearing pressure is greatest for the first 16 inches of soil underneath the footing. After the first 16 inches, the soil-bearing pressure diminishes by about half. Then again, by about two-thirds after the next 16 inches of depth.
The Importance of Thoroughly Compacted Soil
While the first 16 inches in this example are the most important, it’s easy to see how having soft or sandy soil a bit deeper than that can have an impact on how your foundation settles. For that reason, it’s essential to make sure that the soil is thoroughly compacted before building the foundation. If you encounter clay, soft soil or sandy soil anywhere on your property during the excavation, it’s probably a good idea to consult with an engineer before going any further.
Other Details to Consider
- Footing dimensions: The wider a footing is, the more it will spread the weight of the house into the soil. Wider footings can give you more stability.
- Placement of the footings: A footing that is placed off-center can create problems for the wall because the weight will not be distributed evenly. Also, undue stresses will be placed on the structure.
- Water in the soil: Finding water in the soil during excavation can be a big red flag, so be sure to consult with an engineer if you encounter any during the excavation for your foundation. You may need to fill the form bottom with stones and compact them into the mud to provide greater stability.
You want your house to be as stable as possible, but Mother Nature doesn’t always cooperate. Keep these pointers in mind before pouring the foundation for your home, and you can avoid serious problems later.