The 4 Main Types of House Foundations
Why Foundations Matters to Homeowners
Whether you’re buying an existing property or looking at building a home from scratch, it’s important that you understand how the house’s systems and structures function. And that includes the foundations.
Granted, few people consider a home’s foundations when they’re visiting open homes or looking at perspectives for new builds. But as these are a key part of a building’s overall structure, they are critical.
In fact, your home’s foundations can affect much more than the structural integrity of the property. More on that later, but for now, let’s take a look at the main foundation types and the pros and cons of each.
Types of Foundations
There are myriad ways of building foundations, and plenty of different techniques and approaches that can be followed. But foundations can still be categorized into four main types. Here’s an overview of each.
As the name suggests, basement foundations provide you with additional living space in the form of a basement. These foundations begin at least eight feet below surface level to provide enough space for the sunken living area. As a general rule, basement foundations roughly match the home’s ground-level floor space.
In basement foundations, structural foundation walls are placed above concrete footings around the perimeter. These walls ensure the basement can withstand any expected pressure from outside and provide the structural integrity needed to keep the above-ground portion of the house solid and stable. Because of the nature of basement foundations, concrete slab walls, beams, and footings are the building material of choice.
While the obvious benefit of basement foundations is extra room to live and play in, there are a few drawbacks and this type of foundation isn’t suitable for all regions. For example, if you live in an area prone to flooding, you’re better served by another foundation type.
Here’s a quick look at the key pros and cons:
Basement Foundation Pros
- More floor space, sometimes as much as double the home’s surface area
- Durable and resilient
- Suit cold climates where a home’s foundations have to be placed below the frost line anyway
- Flexible design options such as daylight basements where one or more sides are not underground
Basement Foundation Cons
- Basement foundations are widely recognized as being more expensive than other types
- If poorly installed or maintained, basements are notorious for issues such as mold, poor ventilation, and mildew
Crawl Space Foundations
The name might sound like something from a B-grade horror flick, but crawl space foundations are a very popular choice. In crawl space foundations, short stem walls (also known as foundation walls) are erected below the home. This creates a gap between the base of the foundations and the property itself — aka a crawl space.
Depending on the height of the stem walls, the foundations may be spacious enough to act as a storage space or even house some of the home’s essentials, such as the furnace. In a similar vein, with crawl space foundations, the home’s infrastructure including its plumbing and wiring are easily accessible, albeit via a short crawl.
One clear benefit to crawl space foundations is their potential to lift your home. If you’re building near the ocean, for instance, you might be able to gain a few critical inches to secure a dream view. But it’s not all plain sailing and there are a few drawbacks.
Crawl Space Foundation Pros
- May improve a home’s overall aesthetics and help raise a property
- Easier access to the nuts and bolts of the house, including the plumbing and wiring
- Can provide storage space
- Far less expensive to build than basement foundations
- An excellent choice in earthquake-prone areas as the stem walls help protect the home from seismic activity
Crawl Space Foundation Cons
- The gap created between the home and the bottom of the crawl space needs regular maintenance to prevent issues
- Mold and mildew can occur if maintenance has not been kept up with
- Crawl spaces may make homes harder to heat in the cooler months, which leads to higher energy consumption and power bills
Concrete Slab Foundations
A popular choice, concrete slab foundations are quick to create and less expensive than other foundation types. Also known as monolithic and mono-slab foundations, in concrete slab foundations, a flat slab of concrete is poured then leveled in one go.
But it’s not just concrete, of course. Perimeter beams provide structure to the slab while rebar and other reinforming materials run through the concrete body of the slab to help increase stability and longevity.
For many homeowners, the key benefit of concrete slab foundations is that there’s no required maintenance, especially compared to basement and crawl space homes. That’s not to say you will never have to see or think about your foundations because if something goes wrong, you will and it can be a palaver.
For example, if you need to access a plumbing or sewerage pipe to fix an issue, these are embedded in the slab, so access requires cutting away part of the slab to remedy the problem. As you can imagine, this equates to higher costs for what would otherwise be basic maintenance.
Concrete Slab Foundation Pros
- Cheap and fast to install
- No regular maintenance requirements
- Mold and mildew cannot accumulate under the home as there’s no gap for these to accrue in
- Reliable and durable if poured properly
Concrete Slab Foundation Cons
- Little protection from seismic activity
- If improperly poured, the slab may have significant vulnerabilities and weak spots
- In very cold climates where the ground freezes then thaws, cracks and other structural issues in the slab are common
- With some plumbing issues, you’ll need to have your slab cut to access the pipe
While wood doesn’t initially sound like the best choice for foundations what with termites and all, properly made wood foundations remain popular in warmer, dry climates.
Here, builders will use woods that are resilient in the face of insects and mold such as cedar, redwood, and cypress. You guessed it though, these wood types are all pretty expensive, so some homes have wood foundations made with treated, cheaper wood.
One pro point to wood foundations is that there’s no heavy masonry or concrete pouring work so depending on the wood used, these foundations can be cheaper than even concrete slabs.
Wood is also commonly used in hot climates where builders want to raise the home above the ground to ensure good airflow and ventilation. In these cases, the wood plinths are buried in concrete sockets for better stability and durability. Wood foundations should never come into contact with water.
Wood Foundation Pros
- Wood foundations can be insulated and help keep a home warmer and less draughty overall
- May be less expensive than concrete foundations because the material is easy to work with and there is little heavy machinery involved
- A good financial choice in remote areas where it would be expensive to bring in concrete and masonry workers and materials
- A sustainable building material that won’t off-gas as concrete does
Wood Foundation Cons
- Only suited to areas where the ground stays relatively dry
- Wood foundations will not last as long as concrete foundations
- If the wood was not treated properly, the home’s structural integrity can be affected by mold and/or insects
- If the wood rots and you do not notice, your home may become unsafe, and/or you’ll be faced with tens of thousands of dollars worth of repair bills
Why Foundations Matter to Homeowners
Above and beyond keeping you and your family safe and sound, the foundations of your home can make a huge difference when it comes to your homeowner’s insurance policy and premiums.
If you’re in the process of building a new house or you’ve just bought an existing property, it’s likely that you’re somewhat stretched financially, and the last thing you need is huge premiums.
According to CNBC, the average homeowner’s insurance premium is $1200 per year. A small drop in the grand scheme of things, and priceless in terms of the benefits having insurance confers, but it can still feel like a lot when you’re handing out money hand over fist to get into your new home.
If your home’s foundation type is ill-suited to the climate or environment, these premiums are likely to rise considerably. Or, in a worst-case scenario, your home’s foundations won’t be covered by your insurance at all.
Our top tip is to speak to an insurance provider before building and find out the company’s policies regarding foundation types and policy coverage. And if you’re purchasing a new home, take your time to learn more about the house before signing on the dotted line. Find out if it’s insurable or if its foundations roadblock you from even getting full homeowner’s coverage.
That concludes our round-up of the four main types of foundations and why knowing a little more about each, including their pros and cons, matters to homeowners.
Now that you’re equipped with some more information on foundation types, you should feel confident heading out into the housing market and asking the right, foundational questions. Interested in reading more about this topic? Read our Blog Post about How to Estimate the Replacement Cost of Your Home.