Different Types of House Foundations
Good foundations are critical for building safety and durability. Check out some of the various types of house foundations here.
House Foundation Materials
1. Concrete
Concrete is one of the most fabulous building materials available, as it can be used for virtually every building project you can think of. Concrete and foundations mix very well. A concrete slab can be poured, which makes it easy to work with.
Additionally, the underground walls that make up the rest of your basement are typically constructed of concrete. Foundation walls are fixed and easy to construct with concrete, which is why it is seen in basements so commonly.
When working with concrete, a wooden frame must first be constructed. This frame will have the concrete poured into it and will be left until the concrete hardens. Once the concrete hardens, the frame can be removed. The concrete walls and foundations should support themselves.
T-shaped foundations are a very common type of concrete foundation. They are primarily seen in areas where the ground freezes because they are designed to extend below the frost line to resist frost damage.
In t-shaped foundations, a flat section of footing, wider than the intended wall, is placed deep under the ground below the frost line, forming the whole perimeter for the basement.
A concrete wall thinner than the width of the footing is then poured onto the footing high enough past the ground level. The relationship between these two parts is how t-shaped foundations get their name because the shape they create resembles an upside-down letter T.
T-shaped foundations have a layer of gravel at the bottom followed by a layer of wire mesh used to reinforce the concrete floor poured onto it. Overall, the effect is a highly stable foundation that is able to survive anything that is thrown at it, including frozen ground.
2. Metal
When working with concrete, metal reinforcements are normally added. The metal will be fixed into the concrete as it dries, providing extra strength and rigidity. Metal is a very important component of your foundation.
3. Concrete Blocks
Concrete blocks are large brick-like materials that are made from concrete. They are bigger than regular bricks, which makes laying them much easier and quicker.
Concrete blocks are also known as breeze blocks, as they are much lighter than you might imagine. It's important to choose heavy-duty concrete blocks when building foundation walls because light walls simply won't be up to the job.
Exterior-grade concrete blocks are frost-resistant, which means the blocks won't be destroyed if water gets inside and freezes. Concrete blocks can be used the same way as bricks, just much more quickly.
4. Bricks or Stones
Some older houses have brick or stone-built foundation walls. These are just as strong as concrete but are more susceptible to water damage because of the gaps between the stones.
5. Wood
When most people think of a foundation, they think of concrete. However, working with wood can be a great way to create a sturdy base for your house. Pressure-treated wood, which is impregnated with lots of chemicals, can be used, as it will prevent the wood from rotting or being eaten by termites and other pests.
Types of Foundations for Houses
Beyond just materials, there are a few other things to consider when deciding between different types of house foundations. There are three popular types of house foundations.
1. Full and Daylight Basements
Out of the three main house foundation types, full and daylight basements are the deepest. A “full” basement is one that's at least seven feet with beams, girders, and other obstacles projecting no more than 6-inches below the required height.
The basement size typically matches the majority of the floor space of the level above it. This type of foundation is commonly found in newer and more modern houses.
Full and daylight basements have structural walls that bear on foundation footings, which run along the perimeter of the basement. These footings typically extend below the line of which the ground freezes in winter, also known as the frost line.
The term “daylight basement” refers to a variation of a full basement. Here, the foundation is built along a slope, and one or more of the foundational sides are fully embedded into the ground. As the slope descends, applicable sides of the foundation are exposed, allowing for large windows and doors to allow daylight to enter the space.
While older homes with basements of this sort are commonly made of stone walls and are typically shorter in height, more modern homes with this foundation are made of poured concrete or mortared concrete blocks.
This type of foundation has a range of benefits associated with it. First, it gives homeowners the power to convert the area into additional living space within their homes. Finishing a basement can nearly double the amount of living space in some homes. This space also has the ability to be heated and cooled like the rest of the house if the owner wishes.
While this foundation type tends to be the most highly desired, there are some associated disadvantages. First, some basements are prone to flooding in the event of heavy rain. Additionally, basements are the most expensive type of foundation.
2. Crawlspace
The next type of foundation that is commonly found in homes is one that creates a crawlspace. This is made of short foundation walls that usually stand on footings. The name of this foundation type comes from the fact that since the space is so short, you have to crawl through it rather than walk. These foundation types are typically no more than 4 feet tall.
Crawlspaces are usually unheated. Similar to full basements, this foundation is usually made with poured concrete or mortar concrete block.
This type of foundation has several advantages. Although only providing limited space, it’s still good to use for extra storage. This type of foundation is also more affordable as it requires less excavation and less material to be built.
One major disadvantage of this foundation type is that it doesn’t provide any additional living space in a home like a full or daylight basement can do.
3. Slab-on-Grade
The least popular type of foundation is slab-on-grade. This is a solid concrete slab that rests on top of the ground. These are commonly built in climates that don’t experience ground freezing and thawing, but they can be insulated in such a way that they become resistant to frost and frozen ground.
The idea of a slab-on-grade foundation means that these homes do not have basements. Instead, the entirety of a house rests on top of a large slab of concrete. Since the depth of a basement doesn’t exist with this foundation, it’s commonly called “shallow."
This type of foundation is usually less expensive than its alternatives, which is a big advantage. This type of foundation can also offer better protection against termite infestation, which is more popular in warmer climates, where this foundation tends to exist the most.
There is a recognized downside of slab-on-grade foundations. With these foundations, water supply and drainage pipes are encased in the concrete. Should there be a problem with pipes in a home with this foundation, the concrete slab has to be cut into in order to gain access to the pipes. Additionally, this foundation type lacks storage space within a home.
Slab-on-grade foundations also have a layer of gravel below them that provides drainage; however, even the single slab of concrete for which this kind of foundation is named is more complicated than it appears at first.
They are thicker at the edges than in the center. The thicker part of the foundation is connected to the thinner part by a gradual incline. In addition to this feature, slab-on-grade type foundations have a variety of features that increase their stability and strength. For one thing, the slab contains a wire mesh for increased durability. The slab can also be reinforced with rebar (reinforcing bar).
Weather-Proofing Materials
Almost all basements can suffer from water damage because they are built underground. That means that some form of waterproofing material must be applied if you want to use the room. There are many different types of waterproofing treatments for foundation walls.
Checking the Conditions
Whichever materials you use to build your foundations, it's essential that you check the condition of the foundations on a regular basis. If you see any large cracks developing, then you must seek a professional opinion.
Making the Foundation Last
Foundations are one of the most important elements of a house and one of the most difficult to fix when damaged. Foundations, however, take a lot of abuse over the years, including everything from water damage to improperly poured foundations.
To ensure your foundation is in good shape, you should periodically assess it. Start by performing a walk through in the interior of the home. Take note of any cracks you see in the ceiling or walls, windows that have trouble shutting, or doors that are no longer level.
Then do another inspection of the exterior of the house. Keep an eye out for any cracks along the foundation above the basement or crawlspace. Also take note of any sagging features, like chimneys or porches, and any loose mortar joints if you have brick siding.
If you do not notice anything out of the ordinary, then the foundation of your home is likely in great shape. If you did see anything that concerns you, then you should have it inspected by a professional foundation repair company. The faster you get any issues fixed, the better your foundation will be in the long run.
Water is the most common issue facing foundations. One of the biggest water-related issues stems from improper drainage around the house. If you are having issues with your soil, consider installing two feet of rocks around the entire perimeter of the house.
This will help ensure water drains away from the foundation during the wet season. You should also check your gutters on an annual basis and make sure they are properly draining water away from the house.
Plumbing leaks are another way in which water can wreak havoc on your foundation. It is usually recommended to have the plumbing inspected on a yearly basis to avoid any major incidents.
Not only will catching the leaks early save your foundation, but it will also help you save thousands on your monthly water bill. Taking this approach also helps prevent mold buildup that results from too much moisture around the house.
If you ever notice cracks, do not wait. Instead, fix them immediately before they become a bigger problem. What starts out small can become a major headache and cost if not dealt with early.
Start by cleaning out the cracks and removing dirt and debris. Then fill in the fissure with epoxy that is rated for concrete repairs. Once the crack is filled, keep an eye on it and make note if it gets any wider.
You should keep a log of all of the cracks you notice around the house, including their length and width. Check the cracks for growth on an annual basis and call a contractor if you think there may be an issue. For larger cracks, call in a professional immediately.
Make sure to also be careful when you landscape your home. Good landscaping can add a lot of curb appeal, but it can also be detrimental to your foundation if not done properly. For instance, if you plant large trees close to the home, the roots can dig their way into the foundation and cause serious damage.
Roots can also erode the soil and create a drainage problem. To prevent this, avoid planting trees too close to the foundation. As a rule of thumb, if the branches can reach the house, then the roots can as well.
If your house already has trees that are too close, then consider having them relocated to a different part of the property. You can also install a root barrier around the foundation to prevent any issues.
Conclusion
What is the best type of foundation for a house? It depends. Choosing the parts of a house foundation that work best for you will depend on your needs for space, your construction resources, and the climate in your environment.
If you're ready to consider constructing your own building, check out our guide on how to lay foundations.
