Basement excavation refers to digging out a foundation for a house with enough room for a basement. This is useful if you are planning on using this extra space for another level or at least another room in your home. Because basement excavation can be either very simple or widespread and complex, prices can vary based on the project. You can expect some average costs for most excavation projects, however.
Basic excavation refers to removing enough earth to make room for a single story basement for an average home. This type of basement typically requires contractors to dig down at least eight feet into the earth. For this type of project, the average cost was $1.75 per square foot in 2011. For a deeper basement or for very rocky soil, excavation costs may rise.
Additional costs refer to the extra expenses you might have to pay for services not included in a normal excavation. For instance, most excavations include disposal of earth on site. If you choose to have all the earth taken away, this can add as much as $2 per cubic yard of material. This cost is common, since few homeowners have room on their landscape to use all the dirt.
Many contractors will also offer to do a variety of preparation work for the basement as part of the excavation service. For example, if you want fine grading services to help prepare the surface for laying the foundation itself, this can cost an extra 75 cents per square foot. Stabilization screening, the next steps, can cost $1.10 per square foot.
Excavation on Completed House
If you already have a house and want to add a basement, costs can vary greatly. If you have a crawlspace and simply want to enlarge it to add a basement area, the costs may not go over a few thousand dollars for excavation and concrete. If you want a full basement throughout your house, however, you may have to have the house lifted and the foundation remodeled, which can cost $15,000 or more.