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Digging, building, and finishing a basement typically costs between $60,000 and $150,000*. This significant investment may be the best way to expand the square footage of your home. The final project cost depends on the new basement’s size and layout and the construction method you use. We’ll explore each of these factors below to help you plan your basement excavation.
*Cost data in this article was sourced from HomeAdvisor and Angi.
Major Factors Affecting the Cost to Dig Out a Basement
Basement size, house support, drainage needs, and foundation pouring will dictate your basement excavation costs. Read more below.
Basement Size and Layout
Basement size is the most significant cost factor when it comes to materials and labor needed to dig out a basement. The excavation alone typically costs $75 to $150 per cubic yard of dirt, and you can expect to pay between $30 and $75 per square foot for new basement space. If you want a higher ceiling or a more complex layout, your project will fall into the higher end of that cost range.
Cost by Size
Based on the price range above, here’s how much it will cost to dig basements of varying sizes.
|Basement Size in Sq. Ft.||Cost Range|
Supporting the House
The weight of your existing house will need substantial support as you break ground for a new basement. The quicker and less expensive option is to raise the house on hydraulic jacks for about $3,100 to $9,400. However, this puts stress on the house’s structure and can cause cracks and wall or floor damage. Your home must pass a thorough inspection from a structural engineer to determine if the jacking and raising process is suitable.
The alternative option is called bracing or underpinning, through which support braces are installed at every foundation footing. This process is more time- and labor-intensive and can cost up to $20,000, but your home will be more evenly supported and less likely to sustain damage.
Drainage and Waterproofing Needs
Your basement must have a new drainage system to ensure groundwater doesn’t damage the new concrete walls. A new drainage system will likely cost between $3,000 and $9,000 when combined with necessary plumbing and sewer lines. Depending on the soil and climate, you may also need additional basement waterproofing features around the exterior or interior, which can cost anywhere from $3 to $10 per square foot. Don’t neglect waterproofing and drainage, as they’re far more expensive to retrofit to an existing basement than they are to add during new construction.
Most homeowners who add a basement to their homes start with a crawl space foundation, which they then convert to a full basement. This is easier than breaking up and removing a concrete slab foundation. Either way, the new foundation must be poured for the basement. The average cost of a new concrete foundation, including floors, walls, and footings, is between $10,000 and $30,000.
Professional vs. DIY Basement Excavation
Experienced professional contractors must execute the bulk of this project, but there are a few facets of the construction that homeowners can take on themselves.
You’ll need to hire a structural engineer to plan the new space and ensure your home remains safe during construction. Professional contractors have the experience necessary to handle the digging, navigate heavy machinery, pour the new foundation, handle soil conditions, and plan for drainage. Professionals also know how to meet all necessary codes and acquire building permits for construction.
Only licensed professionals should make structural changes, but once they’ve constructed the unfinished basement and installed the wiring and plumbing, you can take on some finishing tasks yourself, including hanging drywall, painting, and installing basement floors.
Additional Cost Factors
The following factors may also contribute to costs, depending on the particulars of your basement project:
Anything that makes the basement space more difficult for contractors and machinery to access will increase the cost. This includes landscaping features such as trees, existing concrete slabs for driveways or patios, and other obstacles. Basements that are easily accessible will likely cost less. For example, a walkout basement with at least one above-grade wall will be easier and less expensive to dig.
If you plan to use your basement as a living space, you’ll need to insulate the walls and floor to help regulate the temperature. This will also help keep your energy costs low because heat from your home won’t leak into the basement space. Expect to pay between $1,400 and $6,300 to fully insulate a basement, depending on the space’s size and the type of insulation you select.
The type and stability of your yard’s soil will play a role in determining how much excavation and construction will cost. Rocky soil requires more time and effort to excavate, and clay-based soil will likely require a more elaborate drainage system. It’s a good idea to plan for coverage in your budget because you may not know the exact condition of your yard until the excavation is underway.
How to Reduce Project Costs
Although digging is a huge investment, there are some ways to keep costs down.
- Buy materials in bulk: Purchase materials such as concrete, lumber, or drywall in bulk. You may get a better rate if you purchase them yourself instead of going through your contractor.
- DIY the drywall, painting, and trim: Most homeowners can handle these finishing tasks.
- Do your own demolition and site preparation: Homeowners can likely handle relocating landscaping features and renting a jackhammer to break up driveways, walkways, or patios.
- Finish basement in phases: You don’t need to go from no basement to fully furnished living space in one project. Start with the structural work, then complete the basement remodel over time.
- Get multiple estimates: Consult at least three local contractors for quotes to better understand your area’s rates.
- Hire contractors during the offseason: Contractors tend to be busiest in the spring and fall when the weather’s good. They may charge less in other seasons.
Extra Options to Consider When Digging Out a Basement
Once the concrete has cured and the jacks or braces have come off, you’ll have a new space to finish and decorate. General finishing prices range from $7 to $23 per square foot, and the price will fluctuate depending on the factors below.
Electricity and Plumbing
Contractors will occasionally install basement plumbing before the new foundation so the pipes can be encased in concrete. You can decide to add plumbing later, though, for features such as washing machines, bathrooms, or kitchens. This is likely to cost between $1,000 and $3,000, depending on the plumbing’s complexity. You can add new wiring for $3,500 to $8,000, particularly if you plan on using the new space as a home office or theater.
After contractors have insulated it, you can add heating and cooling systems to your space to make it even more comfortable. The most effective and expensive option is extending the ductwork into the basement. If your central HVAC unit isn’t powerful enough to cover the additional space, you may need to upgrade it. Alternatively, you can install a single-zone mini-split system for about $2,000 to $8,800.
Framing and Drywall
You’ll need framing and drywall to create a finished space, especially if you want to section your basement into separate rooms. Framing costs anywhere from $1,000 to $3,000 or more depending on the amount of wall space, and hanging drywall adds another $1.50 to $3 per square foot.
While you can leave the new concrete floor as is, most homeowners choose to install more comfortable, attractive flooring such as vinyl, carpet, or even hardwood. Here are some of the most common flooring options and their material costs per square foot.
- Vinyl tiles: $1–$4
- Vinyl sheet: $1–$5
- Laminate: $1–$6
- Linoleum: $2–$3
- Carpet: $3.50–$11
- Ceramic tiles: $5–$15
- Hardwood: $5–$15
- Stone tiles: $7–$20
The final steps of finishing a basement are usually installing trim and painting walls. Hiring professionals costs about $1,000 to $3,000, but you can handle painting yourself to save on labor costs.
How to Hire a Professional
Digging a basement typically requires hiring separate contractors for the excavation, concrete pouring, waterproofing, and other tasks. Here’s what to keep in mind as you compare professionals:
- All contractors should have a regular contractor’s license and be bonded and insured.
- Check the company’s page on the Better Business Bureau website. You’ll see the company’s rating and accreditation status, customer reviews, and any outstanding complaints.
- Get an itemized estimate so you know where your money is going.
- If you want to hire a general contractor to oversee the project, ask about payment rates and how communication with subcontractors will be handled.
- Look for more customer reviews on sites such as Trustpilot and ask the company for references.
- Make sure you understand the timeline for project completion.
- Some states require special licensure for jobs such as operating heavy machinery or pouring a foundation. Check your state’s requirements and make sure the appropriate contractors have up-to-date licensure.
You can increase your home value and your living space by excavating a basement under your house. Consult with a structural engineer to ensure your home remains structurally sound, and hire experienced contractors for the excavation, support, and foundation construction.
Cost to Dig Out a Basement FAQ
Can you turn a partial basement into a full basement?
Yes, you can expand a partial basement into a full basement. However, it will require excavation, foundation, wiring, and utilities work.
How do you put a basement under an existing house?
To dig a basement under an existing house, the house must first be supported on jacks or braces at the foundation footings. Contractors can then excavate the basement space underneath and pour a new foundation.
What is the cost to excavate a basement?
The digging facet of an excavation project is likely to cost between $75 and $150 per cubic yard. However, the total cost to create a new basement is typically $60,000 to $150,000.
What preparation work is needed before digging out a basement?
You must consult with a structural engineer before digging out a basement to create a plan for excavating a new basement. Your house will then be raised on jacks or braced for support before digging can start.
Is digging out a basement worth it?
Digging a basement is a worthwhile option if you’re not able to expand your home’s square footage with an addition. Once the space is finished, it will add to your home’s value and square footage.