Learn the ins and outs of your home’s home base
A strong, well-built foundation is the cornerstone of a safe and healthy home. For both residential and commercial properties, different types of below-ground reinforcement are available—and sometimes offer advantages other materials or designs simply can't.
In this expert guide, we discuss the seven best types of house foundations you can choose for your build, as well as the pros and cons of each style.
1. Slab-on-Grade Foundation
Slab-on-grade foundations—also called floating slab foundations—are built using a mold. Once cast, the foundation leaves no gap between the ground and structure.
The main drawbacks of slab-on-grade foundations is accessibility below your foundation to things like utility lines. Because slab foundations can't easily be raised, it can also be more challenging (and expensive) to do home renovations.
Concrete foundations cost between $4 and $25 per square foot. Newer designs are better at channeling water away from your home, but some concrete foundations can be prone to water pooling underneath it.
2. Poured Concrete Slab Foundation
Like slab-on-grade, poured concrete leaves no gap between the ground, eliminating the option for a crawl space or basement. The main difference is poured concrete isn't as strong as slab-on-grade, meaning this option may only be available for small-to-moderate sized homes. (Relatively speaking, poured concrete is still extremely strong and durable.)
As a whole, concrete slab foundations are the most popular for buildings, as they're relatively easy to lay and capable of supporting large structures. Poured concrete decreases the likelihood of flooding as compared to crawl spaces and basements.
3. Crawl Space Foundation
Where soil is stable or the ground is sloped, crawl space foundations become a common choice for homeowners.
Where it may lack in strength as compared to poured or slab-on-grade concrete, it offers the advantage of spacing between the home and the ground, making them an especially popular option in earthquake-prone areas for safety reasons. Exterior concrete walls with additional support beams generally made from wood raise the home approximately 18 inches from the earth.
Pest control can be an issue for crawl spaces, as a dark, moist environment void of food traffic is a perfect place for critters to inhabit. Crawl space encapsulation costs, which essentially seals the area between home and ground, can be as much as $15,000.
4. Basement Foundation
Homes with basements are dug the deepest into the earth out of any other type of foundation. Interestingly, the floor of your basement, from a structural standpoint, doesn't technically "count" as reinforcement for your home's foundation. The basement walls provide the bulk of strength and reinforcement.
Basement foundations come with advantages such as weather protection and increased resale value on your home. They can be built on a number of different types of soil and grade, making them a popular choice for residential homes.
That said, due to rising construction costs, the National Association of Home Builders estimates that only about 24% of new American homes are built with basements.
5. Pressure-Treated Wood Foundation
Sometimes called a "permanent wood foundation," pressure-treated wood used to build a frame against dirt during construction can also be an option for your home's structural base as well.
Benefits of a wood foundation include ease of installation and easier foundation repairs due to increased accessibility. However, even pressure-treated wood can be susceptible to rot over time if prolonged water exposure occurs. Areas with good drainage or slopage are best for this type of build.
Hiring a local structural engineer with wood foundation experience is absolutely essential for safety reasons.
6. Stone Foundation
Not seen as much these days—but still a force to be reckoned with—is a natural stone masonry foundation.
Stone foundations offer elegance, minimal maintenance, and incredible tensile strength and durability, not to mention a unique aesthetic. For the right buyer, it could definitely also increase resale value for your home.
A stone foundation may cost as much as $20,000 for a residential home, roughly 25% to 50% more than a poured concrete slab.
7. Insulated Concrete Form (ICF) Foundation
Insulated concrete is made from expanded Polystyrene panels that add insulation and durability to a home's foundation. These interlocking foam bricks can also be installed relatively quickly and come with a 100-year rating.
Insulated Concrete Form (ICF) foundations actually offer more tensile strength than poured concrete. At $7 per square foot, ICF is quickly becoming a popular choice for homeowners for these reasons.
Regardless of the type of foundation you choose for your build, it’s best to hire a local foundation repair company to handle the job for you.