Everything You Need To Know About House Foundations

Everything You Need To Know About House Foundations

Your house foundations influence everything to follow. Contrary to popular belief, home foundations can be as unique as your roof or siding. Choosing the right type is one of the first steps toward building a home. Contractors must consider several details, such as temperature, climate, and budget, before making the plunge.

If you’re considering investing in a new home, you need a refresher on this fundamental detail.

Should you choose a slab house foundation, a crawl space, or a daylight basement? Here’s everything you need to know about house foundation types. We also answer your other burning questions. 

What is the foundation of a house?

Let’s start at the beginning: what are house foundations? A house foundation is the structure on which your home rests. It's essentially the base that supports the weight of the entire structure, transmitting its load to the ground below in a way that prevents the building from moving.

What are most home foundations made of?

Typically, home foundations are made of concrete, though sometimes they can be made of stone, brick, or other materials, depending on the building's design and local construction practices.

Most American homes use concrete slabs and crawl spaces for their foundation. Daylight basements are becoming more popular for families who want to age in place or have adult children moving back in.

House foundation types explained

The proper foundation for your house may be incompatible with someone else’s home, that’s why you need to consider factors such as the environment and your budget before choosing your foundations. Some house foundations are also better suited to people who like to renovate a lot.

Let’s take a look at the most commonly used house foundation types.

Crawl spaces

These house foundations earned their name for the little area of space beneath the home. They are made up of short foundation walls that sit on footings and are usually between three to five feet in length.

There are usually small vents to promote airflow through the crawl space and prevent damage. It’s important to check these space for moisture and water leaks too.

Concrete slabs

Another popular house foundation is the concrete slab. Unlike the propped design of the crawlspace, the concrete slab rests directly on the ground.

Concrete slabs aren’t ideal for very cold weather due to how soil contracts, freezes, and shrinks during a temperature drop. The water supply and drainage pipes are also encased in the slabs, so these will need to be broken if the pipes need to be accessed or repaired. You also can’t retrospectively add a basement or crawl space with this type of house foundation. On the plus side, concrete slab foundations are quite affordable and last a long time.

Daylight basement

A frequently used house foundation is the daylight basement. These foundations are built against a slope, with at least one wholly embedded in the ground, from floor to ceiling, and at least one opening up to the outdoors. They are usually large windows and doors on this side to bring in daylight.

This house foundation type creates a homey living space and is much less prone to mold and mildew than regular basements. Many homeowners like to turn their daylight basement into a home gym, extra room for guests, or storage space.

Insulated concrete form (ICF)

Insulating concrete forms are made of high-density foam and are used to form the wall structure when pouring concrete walls, helping to strengthen and insulate them. With a modular design, they are quick and easy to use. They’re also highly durable, particularly through natural disasters like hurricanes and earthquakes.

They are a popular choice because they’re insulating properties make the house up to 60% more energy efficient, and they’re cheaper to upkeep because they’re not made of damage-prone wood. However, ICF isn’t very porous so it can cause indoor humidity. Adding windows and doors retrospectively is also tricky. 

Less common home foundations

There are three other house foundation types, though these aren’t as common. They include:

  • Wood foundations: Though they were once popular across America, these house foundations are prone to rot and insect activity, meaning most people avoid them for new builds.

  • Pile foundations: If the topsoil is too unstable or weak to support a house, piles are used as deep-seated stabilizers that can reach the more rigid rock or soil.

  • Stone foundations: These are highly durable but costly. So, while they can still be found in older homes, they’re not commonly used in new builds. 

How do you build a foundation for a house?

Human society has had plenty of time to perfect the art of building the foundations of a house. While techniques vary a little from business to business, we have the general steps for a concrete slab foundation below.

  • Create an accurate site plan

  • Study the soil and climate for compatibility

  • Prepare the site

  • Pour concrete to create the base

  • Erect concrete walls

  • Complete the slab floor

All projects need an outline. We provide custom site plans with a turnaround of twenty-four hours, Monday through Friday.

How do you dig a house foundation?

There are a few steps involved in digging a house foundation.

  • Digging a house foundation starts with studying the soil — which should be compacted and thick — to determine stability.

  • Next, you need to check your site plan to determine the location and dimensions of your foundations, and map these out on your site.

  • The site is then excavated using heavy machinery. As the trench needs to be deeper than the frost line, a house foundation is usually a minimum of five feet, though colder climates often need extra room due to the build-up of frost.

  • Finally, the trench needs to be leveled and compacted. 

How deep are house foundations?

House foundations need to be deeper than the frost line, so are usually a minimum of five feet. However, in colder climates, they are usually over six feet to accommodate the frost build up. The depth of the house foundation will also depend on the type of foundation used, as basements may need to be deeper to be usable as living space. 

How thick is a house foundation?

Again, this really depends on the climate you live in and the soil beneath the house, but typically foundations are between eight and 10 inches thick. As a general rule, the thicker the foundation, the sturdier the house, as it helps to protect the house from the elements and from shifting or settling soil.

How long do home foundations last?

The longevity of a home foundation depends heavily on the carpenter's skill and the environment's compatibility. Some home foundations can stand firm for centuries.

Crawl space foundations usually last around fifty years. On average, concrete slab foundations can last up to one hundred years. You can use a few techniques to strengthen your foundation and give it a few more years of longevity.

Speaking of which…

How to fix house foundations

Do you worry your foundation may show signs of age earlier than usual? Contractors have several valuable techniques to strengthen foundations on the fly. 

How to fix house foundation


This technique is used if the foundation is starting to show cracks. Think of this tactic like giving your foundation a helping hand.

The most common underpinning techniques include:

  • Mass pour: This involves excavating the existing foundation and pouring concrete into the voids to create additional support and redistribute the load-bearing capacity.

  • Pile and beam: This involves driving steel or concrete piles into the ground beneath the existing foundation to provide additional support. Horizontal beams are then installed to connect the piles, transferring the load of the structure to the deeper, more stable soil or bedrock.

  • Piled raft: This technique combines elements of both mass pour and pile and beam techniques. It involves constructing a reinforced concrete raft foundation beneath the existing foundation, supported by piles driven into the ground. This method effectively spreads the load of the structure over a larger area and can be particularly useful in areas with poor soil conditions or where traditional underpinning methods may not be feasible.


This term is a little misleading since mud isn’t the key ingredient. Instead, it's a technique used to raise and stabilize concrete slab foundations, as well as bolster steps, decks, or porches. The process involves drilling small holes into the affected concrete slab and then pumping a slurry mixture (usually a blend of cement, soil, and water through the holes to fill voids, compact soil, and lift the slab back to its original position. This helps to strengthen and level the foundations. 

House lifting and leveling

Does your home have a high risk for flood damage? You may need to use house lifting and leveling to protect your hard work.

This technique involves physically raising the existing structure, either partially or completely, above its current foundation level. Once elevated, the house is securely supported on temporary or permanent structures while the existing foundation is either reinforced or replaced with a higher one. 

How much does a house foundation cost?

The cost of your house foundation varies based on your chosen type. On the cheaper end of the spectrum are concrete slabs, which cost just over $8,000. On the other end are basement foundations which are closer to $35,000.

According to The Spruce:

  • A concrete slab foundation costs on average $8,250.

  • A crawlspace foundation costs around $14,500.

  • A basement foundation is around $34,250

Choosing your house foundations

House foundations are as unique as we are. We recommend giving this step a little extra consideration, because a poor foundation will result in a shabby house.

Once you find the right foundation for your needs, the flooring and roofing will easily follow suit.

Give your home foundation its own foundation. Contact us today for a custom site plan that steers your project in the safest direction possible.

House foundation FAQs

What factors should I consider when choosing a foundation for a house?

Consider environmental factors such as climate and soil, as well as the intended use of the space and budget constraints.

Which foundation type is best for a home in a seismic zone?

While not directly mentioned in the article, generally, deeper foundations like crawl spaces and basements are preferred in seismic areas for their ability to better absorb earthquake shocks.

Can daylight basements be used in any climate?

Daylight basements are suitable for sloped terrains and can be used in various climates, especially where additional living space is desired.

What is the most cost-effective foundation type?

The article suggests that concrete slabs are quite affordable and offer long-lasting benefits, making them a cost-effective option for many homeowners.

How do I choose the right soil type for a house foundation?

Soil study is crucial; the best soil for foundations is compact and thick to provide stability and reduce the risk of settling or other issues.

What maintenance is required for crawl space foundations?

Regular inspections to check for water damage, mold, and structural integrity are necessary to maintain the health of crawl space foundations.

Are there environmentally friendly options for house foundations?

While not specifically addressed in the article, using sustainable materials like recycled concrete or locally sourced materials can be more environmentally friendly.

How can I modify an existing foundation to improve its insulation?

Techniques such as adding insulation panels to the exterior of basement walls or under slab areas can significantly improve thermal performance.

This post was originally published on 2022-06-24 by Ryan Crownholm. It was updated on 2024-05-08 to reflect the most recent data.

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  • Ryan Crownholm