How Much Does a Foundation or Basement Cost in 2024?

House Foundation Costs Per Square Foot

Here’s a breakdown of average costs per square foot for common foundation types:

Monolithic Slab

Monolithic slab foundations cost between $5,200 and $13,000, averaging $5 to $16 per square foot. This type involves pouring the footings and slab all at once, making it a quicker and often more cost-effective option due to reduced labor costs. Monolithic slabs provide a thick, sturdy base ideal for supporting load-bearing walls and work best on level ground.

Stem Wall

Stem wall foundations cost between $7,000 and $21,000, with the stem wall itself costing $6 to $18 per square foot. This type involves more labor and materials because it includes a poured concrete slab, foundation walls (stem walls), and footings that extend into the ground beneath the walls. Stem walls are ideal for sloped lots since they can accommodate varying heights and provide a stable base on uneven terrain.

Pier and Beam 

Pier and beam foundations, also known as post and pier, cost between $8,000 and $15,000, or $6 to $12 per square foot. This foundation uses piers and posts to support horizontal beams, creating a crawl space that’s perfect for housing electrical, plumbing, and HVAC systems, making maintenance easier. Pier and beam foundations are excellent for earthquake-prone areas because they can accommodate ground shifts better than other types, reducing potential damage.

Crawl Space

Adding a crawl space to your foundation costs $6 to $18 per square foot, totaling $10,000 on average. While not a foundation type itself, a crawl space is created by foundational designs like stem walls or pier and beam foundations. Homeowners appreciate crawl spaces because they provide convenient access to plumbing, electrical wiring, and ductwork, making repairs and maintenance easier. Some crawl spaces are even spacious enough to house an HVAC unit or water heater.

If unventilated, they can harbor moisture and promote mold growth. There are several ways to combat this—like insulation and vapor barriers—to consider during planning. Measures for preventing potential moisture issues include:

• Insulation costs $1–$5 per square foot

• Vapor barriers cost $0.50–$0.70 per square foot

• Dehumidifiers cost $1,300–$2,800

• Crawl space to basement conversions costs $60,000–$150,000

• Sump pump installation costs $650–$2,050

Basement Foundation Cost

Basement foundations cost between $24,000 and $148,000, or $20 to $37 per square foot. While this is the most expensive foundation option, a finished basement can significantly increase your home’s living space and offer a strong return on investment.

“The opportunity to bring daylighting into the basement allows you to use more of your home’s space without feeling like you are underground. This is important as more people opt to work from home. A naturally lit basement is a boon for resale as well.” Cati O’Keefe, Expert Home Building & Sustainability Contributor.

Walkout Basement

Installing a walkout basement costs $37,000 to $191,000, pushing your project closer to $20 to $55 per square foot. But it opens your basement for a future rental unit. With rental income, you can make back your investment in 2 to 5 years. You’ll need to install a few other items to meet code requirements for a rental. You can wrap these up in your basement remodeling costs or split them up as follows:

• Kitchen installation costs $5,000–$125,000

• Egress window costs $2,500–$5,400

• Adding plumbing and electrical work costs $3,000–$9,000

Labor Costs to Build a Foundation

Labor costs for building a foundation range from $4,500 to $18,500, accounting for about 40% to 60% of the total project cost. Keep in mind that labor rates can vary based on your location; areas with a higher cost of living may have higher labor charges.

Other Types of Foundation Costs

Other foundation costs range from $500 to $39,000 for modular and mobile homes and garages. Most of the price comes from the type of installation and how thick and reinforced it needs to be.

Garage

A garage foundation costs about $6 to $12 per square foot. You can expect to pay $2,000 to $7,000, depending on the size and number of cars to accommodate. Attached garages cost less to build than detached ones. 

Shed 

A poured concrete foundation for a 10-by-16-foot shed costs about $1,000. A less expensive option is a gravel pad, which costs about $200 to $300 for the same size shed.

Block

A block foundation is a great option for larger homes, and it uses stacked cinder blocks that are cemented together using mortar and reinforced rebar. This type of foundation costs $9 to $15 per square foot, or $11,500 to $19,000 on average.

Foundation Installation Cost Factors

Even with a poured slab and basement, you’ll need to consider other factors that influence your budget, such as inspections, permits, site preparation, soil composition, engineering, and extra excavation costs.

Permits

Obtaining the necessary building permits is a crucial step and can cost between $450 and $2,300, or about $1 per square foot on average. Permit costs vary by location and the scope of the project. Ensure you factor these into your budget to avoid legal issues or construction delays.

Foundation Inspection

Foundation inspections cost $300 to $1,300. Expert structural engineers spot weaknesses and potential failures. They’re excellent to employ when repairing a foundation, installing one under an existing structure, or after your contractor has finished the project. As part of the permitting process, most locations require a basement to pass inspection before work can continue.

Soil Testing

Laying a foundation requires a plan. To start, test the soil to understand its condition and type. A geotechnical soil test required for construction costs $1,000 to $5,000.

Drainage and Heat Radiation

Factoring in radiant heat and drainage will add to your project estimate.

• Radiant floor heating: $6–$20 per square foot

• Drainage features: $1,100 to $6,500 on average

Plan these upgrades in advance—it’s far less expensive to install these during construction than later. Your pro needs to place drainage pipes and hydronic radiant heat tubes before pouring your concrete slab. You can install newer electric radiant heating later for the same price.

Sealing and Retrofitting

Sealing or waterproofing concrete costs $1,900 to $7,300. In general, concrete sealants add $0.50 per square foot for the materials. Not all basements need sealant, but it helps to avoid future repairs. Repairing water damage costs $3,000 or more. Extreme damage can lead to complete rebuilds.

Piles

Installing piles costs $20 to $60 per linear foot of pile with a minimum cost of $28,000. That price includes labor, equipment, and materials. Although the terms often get used interchangeably with “piers,” they serve a different purpose. Piles underpin various foundation types, bypassing poor soil to bedrock when the soil isn’t good enough to build directly upon.

Piles aren’t a standalone foundation, so add the following prices to other foundation types.

You’ll use piles for extra reinforcement in the soil. This is especially true in loose soil or where you can’t easily reach higher-bearing-capacity soil. You can also use piles to repair bowed or sagging foundations. Your pro does this by driving them next to the existing walls and tying them together.

Driven deep in the earth, piles transfer the weight of the foundation past the poor soil to solid bedrock. You can use them under a slab foundation or under pier and beam foundations. Always hire a structural engineer for pile foundations.

DIY vs. Hiring a Pro 

Building a foundation is a complex task that requires expertise in soil types, hydrostatic pressure, and structural engineering. Improper installation can compromise the entire structure of your home. Professionals have the necessary equipment and knowledge to excavate, grade the soil, and pour concrete correctly. It’s highly recommended to hire a licensed foundation contractor or a local general contractor to ensure your foundation is built safely and correctly.

How HomeAdvisor Gets Its Cost Data

No place is more important than your home, which is why HomeAdvisor connects homeowners with local pros to transform their houses into homes they love. To help homeowners prepare for their next project, HomeAdvisor provides readers with accurate cost data and follows strict editorial guidelines. After a project is complete, we survey real customers about the costs to develop the pricing data you see, so you can make the best decisions for you and your home. We pair this data with research from reputable sources, including the U.S. Bureau of Labor Statistics, academic journals, market studies, and interviews with industry experts—all to ensure our prices reflect real-world projects.