
When people want to expand their homes, they typically think of expanding upward or outward. But what about expanding downward? One option to create more space, or even just create a better space, is to dig out a basement beneath your existing home. You can do this if you need a larger basement, want to expand your crawlspace, or want to add an entirely new basement.
While digging out a basement won’t be the right solution for every homeowner, it certainly has its benefits. However, it must be done by experienced professionals to ensure it gets done right. After all, we’re talking about the foundation of your home.
Check out these common methods for digging out a basement.
What is a Basement Digout?
When you dig out a basement, you dig into the space beneath your home and set a new foundation, in a sense. The digging part works down into the dirt, rock, and any other debris and digs it all out to clear the space. This is what happens for new construction that builds a basement foundation before ever building the home.
However, you can also dig out a basement on an existing home. This takes expertise and the ability to do it right. The home has to be properly stabilized, and the company needs to be able to dig beneath the existing property without causing any damage to it or surrounding properties.
5 Top Methods to Dig Out a Basement
While different contractors may use different approaches, these five methods are the most common choices to dig out a basement.
1. Top-Down
Top-down basement digouts are specifically used for high-rise buildings. Before they even start digging, they first build load-bearing walls and a concrete floor to prepare for the structure. Then, they follow this process with digging out the basement space.
This option is preferred during the construction phase, because they can construct the basement and work on it while also working on the top of the building at the same time. It’s a dual approach.
2. Open-Cut
The open-cut basement digout is one of the most affordable options to use. This approach creates a downward slope within the basement space so that no retaining walls or structural additions have to be built or used for stability. The slopes into the basement help hold everything in place.
The cantilever open-cut method puts a twist on the process, and they do use retaining walls for this because it’s used for deeper basements.
3. Bracing
Bracing can be a pricey option for a basement digout, but it’s typically not the most expensive. Here, they use horizontal struts to brace the structure and help to offload weight of the structure from the retaining walls.
When done right, the horizontal struts can be part of the permanent foundation framing, making it useful in more ways than one. It’s less complex than some methods and it’s a common choice for homes.
4. Anchored
Depending on the stability of the structure and the surrounding earth, using an anchored digout approach can help to provide stability. However, there are very strict requirements to be able to anchor, and this cannot be used in soft clay or sand.
With the anchored digout, steel anchors are driven into appropriate soil and through a retaining wall. This provides stability and anchors the structure during the work phase.
5. Island Digout
Finally, the island method takes a unique approach that’s actually one of the safest. The professionals will start by digging out a small area that reaches near the center of the basement, much like an island. They work from the inside to the outside, creating a slope against the retaining walls as they go.This is a combination of the bracing method and open-cut method and one of the most preferred options to use.
Choosing the Best Basement Digout Method
It can be hard to figure out which method you want to use. But you shouldn’t be making that decision on your own. Instead, consult with a professional company that has experience with digging out basements. They will be able to closely inspect your structure, your surroundings, and your plans to determine the best method to use.
These are some details to consider.
Type of Soil
The soil around and under your structure will impact what type of digging can be used and what may be needed as well. Certain soil materials may require you to dig deeper or to be more cautious about how you brace your structure. The soil will heavily impact how far you have to dig for safety reasons.
Topography
What does the landscape look like around your structure? Are you on a hillside? How close are the neighbors? Details like these impact what type of digout method can or should be used. There are a lot of factors to consider so that the professionals can plan how to appropriately dig out to create your basement, while also supporting the structure.
Building Size and Details
With a home, there may not be as many variables, but the size and the scope of your structure will matter. It matters even more with big office buildings, high-rises, and anything that is a massive structure. The right method will depend on the size, weight, and scope of the building in question.
Type of Construction
Where you are in the construction process could also make a difference. For example, this is much easier if this is brand-new construction. However, when a structure is already in place, things like bracing and stability or support have to be considered so the structure remains solid and stable during the digout process.
Always Consult a Professional Digging Company
It is no small project or task to dig out a basement. This will be a very detailed project and it takes absolute precision to get it right. Don’t hire a local handyman to come in and start digging. Instead, work with a professional company that has experience with basement digout projects and will be able to help meet your needs and get the project done right!