House Foundation Cost

• Foundation costs vary significantly by region. Other factors include the thickness and psi (pounds per square inch) rating of the concrete, and the type of steel reinforcement used. Clearing, grading the land and digging may be included or billed separately. See Land Clearing, Land Grading and Excavation.
• A slab foundation for an average 1,600- to 1,800-square-foot family home might cost about $7,000 -$16,000 or more, while a slab foundation for a 3,000- to 4,500-square-foot home might cost $13,000 -$40,000 or more. Factors that affect the cost include local regulations, whether insulation or termite treatment is included, and if footers are included. (Footers are a foundation's thicker and deeper base; ThisOldHouse.com illustrates a good slab foundation design, including footers). Homeowners on a GardenWeb.com forum, report paying $20,293 plus $950 for excavation for a 2,589-square-foot slab in San Antonio, TX; $42,000 for a 4,400-square-foot slab in San Marcos, TX; and $21,000 for a 2,800-square-foot home plus 3-car garage, patio and porch in Arizona, with expansive soils requiring additional excavation, rebar and concrete. Slab foundations are uncommon in the East and Midwest, and are banned in some areas.
• A crawl space foundation might cost $8,000 -$21,000 for an average family home, or $15,000 -$50,000 for a larger house. Typically footers are poured along with short walls that support the home; some crawl spaces provide only 16"-18" between the bottom of the floor joists and the soil, while others are tall enough to crouch inside. Build Your Own House explains the pros and cons of a crawl space foundation.
• A full basement foundation for an average home can cost $13,000 -$30,000 or more, depending on the width and height of the walls, and whether utilities, windows or other features are included. An owner-builder reports spending $790 on excavation, $7,000 to pour concrete footings and foundations, $1,800 for flatwork concrete, $1,000 for sub-rough plumbing and more than $1,000 for windows and window wells, with waterproofing and backfilling (replacing excavated dirt) bringing total costs to about $14,000. The owner of a modular home in Missouri paid $3,000 for excavation work and $15,000 to pour the footer and foundation for 172' of wall 10" thick and 9' high, plus $1,200 for foundation waterproofing, $1,400 for rough-in plumbing, $4,100 for the basement floor (called flatwork), and $1,770 for an I-Beam down the center of the basement, for about $26,500 total. And an Illinois log cabin owner-builder estimates about $17,000 in costs for a 24'x36' basement foundation with 8' walls with the concrete poured professionally but the rest done as a "serious DIY project."
• Foundation repairs on a typical house with moderate foundation damage can cost $8,000 -$30,000. Replacing the entire foundation on an existing home can require raising the house up from the existing foundation by at least several feet and excavating down to the footers; costs can vary from $20,000 -$100,000 or more. These projects are rarely cost-effective.

• Concrete shouldn't be poured in temperatures lower than 40 degrees or higher 90 degrees Fahrenheit. Installing a typical foundation for a new home can take 2-3 weeks including time for curing the concrete, according to BobVila.com.
• Foundations with walls must have a wider and thicker base called footers (many slab foundations also have footers), which spread the weight of the building across a wider footprint. In poor soil a footer may be supported by a pier. AskTheBuilder.com provides an overview of foundation footers.
• Some foundations are constructed with concrete blocks, especially in areas far from a concrete ready-mix plan. Block foundations are less durable than steel-reinforced poured-concrete and are banned in some areas. ThisOldHouse.com compares block and poured concrete foundations.
• AskTheBuilder.com reviews the types of foundations.

• Get several estimates. Ask for recommendations from local contractors or at nearby hardware and home improvement stores.
• Ask about the company's experience and equipment. Check references from previous customers and whether the company is properly insured, bonded and licensed; search for any complaints with the Better Business Bureau.

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