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Let's talk foundations: Basements, Crawl Spaces and Slabs

Do you have a basement? What about a crawlspace? Both? Or are they the same thing? Maybe you don't have either but instead, your home sits on a slab? Who knew foundations could get so confusing!

common types of house foundations

Basements and crawl spaces are easily confused (especially unfinished basements) as they both act as a space under your main living levels. However, a slab is completely different in that it doesn't add any extra space. You may be surprised to find out that all three of these play a similar role — to act as your home's foundation.

Surprisingly, one of the most important features of your home, the foundation, is rarely a choice. The type of foundation built is often determined by the conditions on which the home is being built and the local building codes. In reality, there are many different kinds of foundations but the majority of homes use either a basement, crawl space or slab. Let's define each of them and lay out their pros and cons.


This foundation gets its name because it features a solid concrete slab that is built directly on the ground. Slab foundations are especially popular in warmer climates since cold weather can damage a slab foundation. Slab installation is very simple and the cost for this style of foundation is low.

pros and cons of a slab house foundation


  • Easy installation compared to other foundation options
  • Quick installation
  • Least expensive foundation option
  • Requires little to no maintenance
  • No concerns of mold, mildew, rodents or bugs (there's no extra space for them to crawl into)


  • No extra storage or living space
  • Can be damaged by exposure to cold temperatures
  • Difficult to fix house piping (water, drainage, etc.) — the pipes are covered in concrete so if there is a problem the slab must be cut in order to get to them
  • Offers little protection from bad weather events

Crawl Space

Crawl spaces can literally be just that — a small space barely big enough to crawl through. While many crawl spaces have a very short ceiling height (standard is 2 feet), some homes have a much larger space of 4 feet or so. Either way, this space is much different than a basement in that nothing is finished off so there is exposed dirt underneath.

While the crawl space may have ventilation, there is usually no heating or cooling. Some people choose to "condition" their crawl space by installing plastic film over the exposed dirt to combat moisture issues. Crawl spaces allow for some storage and easy access to piping and other utilities.

pros and cons of a crawl space house foundation


  • Relatively inexpensive to build
  • Allows for easy access to utilities for maintenance or repairs
  • Home floors tend to be warmer since they aren't built directly on concrete and there is a somewhat conditioned space underneath
  • Provides additional storage space


  • Can be susceptible to termite and other pest damage
  • Allows moisture to be trapped, which can lead to mold or fungus growth
  • Flooding is possible with heavy rain so you have to keep an eye on moisture and may need to install a dehumidifier


If you're like most people, you may think that the primary purpose of a basement is to add more living space to a home. And while this assumption is halfway correct, it's actually not the main purpose of a basement. A basement is the most expensive (and involved) of the three foundations. But the expense can usually be justified as basements add the potential for much more finished living space — in some cases doubling the square footage.

pros and cons of a basement house foundation


  • Adds more space to a home with a much lower price per square foot cost than other parts of the house
  • Makes routine maintenance and repairs to utilities much easier (even more so than a crawl space)
  • Built-in storm protection for your family during extreme weather events
  • Is a great multi-season space as it tends to hold heat and cool air very well


  • Most expensive option to build
  • Takes much longer to build than a slab or crawl space
  • Tend to hold moisture and are prone to flooding
  • Can be a darker space since there are often fewer windows and doors
  • Might need to install a sump pump to drain out excess water from heavy rain

There are many reasons why your home may boast a slab, crawl space or basement foundation. Each has their own benefit along with some downfalls. And while your specific location may determine the type of foundation that must be used, it's nice to know that no matter what there are usually some options so you can determine what's best for you and your family!

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