Why Caissons Are Necessary Instead of Continuous Footings

Why Caissons Are Necessary Instead of Continuous Footings

November 2, 2020

Your house’s foundation provides support, a moisture barrier and stability to your home in Hudson, CO. Depending on your home’s type and location, however, the type of foundation and footing you need may vary. As you might imagine, the foundation you’d use for a multi-unit apartment building in downtown Denver would be very different than you’d use for a single-family home built on the side of a hill.

Here’s an overview of foundation types and when you might need to use caissons instead of continuous footings.

The two broad types of foundations

Foundations can be broadly categorized into two different types: shallow and deep. Shallow foundations are usually wider than they are deep, and are made for lighter buildings like single-family homes. They don’t require much digging or boring into the earth, which makes them suitable for ground that can bear the weight of a building without additional reinforcement. Shallow foundations are less costly, too, since excavation is not as extensive.

Deep foundations require boring into the ground. If the ground is soft or sandy, you’ll need a deep foundation to prevent the building from sinking into the earth. The foundation has to be drilled all the way into the bedrock. Deep foundations are how engineers are able to build bridges and anchor them into the earth under the water.

What are continuous footings?

A footing can be used to support beams, posts or columns outside of the main foundation. They bear the weight of the column or post and spread it out. Continuous footings hold two or more columns that are built close enough together to use a shared foundation point. Continuous footings are often rectangular, “L,” “T” or square in shape, and can bear the weight of multiple columns on stable ground. They’re often found around the perimeter of a foundation. Continuous footings are shallow foundations, so they cannot be used in soft or sandy dirt.

What are caissons and when are they preferable?

Caissons are a type of deep foundation. They’re often used for bridges and piers, hillside homes and overpasses, where it’s important to drill down into the solid bedrock. When they’re used to support structures over water, they can be made ahead of time, floated into the area and placed into a dredged area. Alternatively, they can be created on-site with concrete and mesh rebar.

As the ground is drilled to place caissons, engineers can place hollow steel casings in the holes to prevent the loose earth from filling the newly drilled holes.

If you’re building a home in an area with soft or sandy earth, on a hill or another area where you’d need deep bedrock stability, caissons are a smart foundation choice.

Ultimately, the house foundation you need depends on your plans, location and the soil quality. The best way to determine this is to work with an engineer, before you start construction.

For house foundations and house foundation repair in Hudson, CO, reach out to High Plains Engineering & Design, LLC today.

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