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A Comprehensive Guide to Basement Excavation Cost

Have you ever thought about how much space is beneath your home? You may need more storage space, a recreation area, or additional bedrooms and bathrooms to accommodate your growing family.

You can dig a new basement if you want to. Building contractors can lift your house from its foundation and excavate it, then pour a new basement foundation.

In this comprehensive guide, we’ll explore how much you’d need to budget for this project and the basement excavation cost factors you need to consider.

What is Basement Excavation?

Basement excavation is the process of removing rocks, dirt, and other debris to make room for a new basement. It is typically the initial step of building construction work, creating a hole where your new space will be constructed.

You can also excavate the basement after your existing house has been constructed. This process is more complex and requires skilled excavation contractors to dig into the soil and remove excavated debris without damaging the foundation or footings. It is generally more cost-effective to excavate before any part of the building is constructed.

Basement Excavation Cost

basement excavation cost

The cost for basement excavation in new construction can range from $12,000 up to $36,000. That’s roughly $10 to $20 a square foot.

If you plan to dig underground under an existing home, the average cost will be between $40,000 and $50,000. This is about $47-$100 per square foot.

When comparing costs, digging a new basement will cost slightly more than expanding a crawl space. A new basement measuring 1,000 square feet will cost between $22,500 and $45,000. The costs for crawl space extension range between $10,000 and $30,000.

Though crawl space expansion may seem cheaper than the cost to dig out an entirely new basement, you should still factor in all necessary expenses associated with basement construction.

[Read: The Ultimate Guide To Digging A Basement]

Factors Affecting the Cost of Basement Excavation Project

Several factors influence the total cost of a full basement excavation project. Understanding these factors will help you plan and budget effectively:

Size of Excavation

Excavation projects that require large excavations require more time, labor of local contractors, and equipment which increases overall expenses significantly.

Cost: $75 to $150 per cubic yard of dirt removed. 

Raising or Bracing

When excavating a basement, your home requires support to avoid structural damage. While hydraulic jacks offer faster and cheaper solutions, raising can compromise stability; bracing (underpinning) is more time-consuming but does preserve its structural integrity more fully than raising can.

Cost: Raising ($3,100 to $9,400); underpinning ($20,000).


Installing proper plumbing and drainage systems in your new basement is essential and should be taken into consideration when planning for your excavation costs. 

Plumbing costs vary depending on the fixtures you want and the impact on the main sewer line. Drainage systems must be designed to keep the basement dry, especially in areas with a high water table.

Cost: Plumbing expenses for a new basement typically range from $1,000 to $3,000. Drainage systems can cost between $2,000 and $6,000, depending on local climate, soil conditions, and yard grading.


Every major construction project, including basement excavation, requires building permits. Permit costs depend on local building codes and regulations. 

Cost: Budgeting around $1,200 to $2,000 for permits is a reasonable estimate.


Construction worker making concrete slab foundation

Once excavation and plumbing work has been completed, a concrete foundation must be laid. This includes pouring a concrete slab for foundation walls, floors, and footings.

Cost: Typically ranges from $10,000 to $30,000.

Unexpected Repairs

Excavating a basement involves foundation work, which may uncover existing issues. Unexpected repair costs may include foundation repairs, drywall repairs, or frame repairs. 

Cost: Potential costs range from $2,100 to $7,800 for foundation repairs and $50 to $80 per square foot for other repairs.

Can you dig a basement deeper?

Yes, it is possible to dig a basement deeper by lowering its floor. Basement underpinning can increase the height of your basement without reducing square footage. This is an excellent option for those who wish to keep the existing space.

On the other hand, bench-footing involves digging out the crawl space to create a deeper basement, but it may result in a reduction of the overall square footage of the finished basement.

How to convert a crawl space into a basement?

Converting a crawl space into a basement involves the following steps:

  • Build a Scaffolding: Construct a supporting structure to support the weight of the home while the new foundation is being built.
  • Excavate the Crawl Space: Excavate the area beneath the house to create the basement space, which is normally eight feet deep.
  • Pour the New Foundation:  For the basement, add four to six feet of concrete walls surrounding the house, establishing a firm link between the existing and new foundations.
  • Finish the Basement: Complete the full basement space and transfer the home onto the new foundation.
  • Monitor for Settling: Keep an eye on the foundation and basement for a few months to identify and address any potential issues.

Hire the Right Residential Excavation Contractor

Basement excavation offers a fantastic way to expand your property and boost its value. Make sure to consider the factors discussed above when getting basement cost quotations from local contractors.

For successful basement excavation projects, trust the experts at Aspire Construction Group in Arizona. Contact us today to discuss your excavation needs for your dream space!

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