crawl spaces vs. basements

Most homeowners know they have some sort of space under their house … but is it a crawl space or a basement, and are they the same thing? Especially for unfinished basements, or half crawl space/half basement spaces, the line between crawl space and basement can be pretty blurred. To understand how best to maintain and use each space, however, it’s important to be able to distinguish between the two.

To sum up, the primary difference between a crawl space and a basement is the ventilation needs of each space: basements are heated spaces (i.e., properly insulated and not ventilated, regulating the temperature of the space), while crawl spaces are unheated spaces (i.e., properly insulated and ventilated, promoting the flow of air and moisture). Additionally, basements have a higher clearance than crawl spaces, and are thus much better suited to be livable space in the home.

Knowing the difference between crawl spaces vs. basements is helpful, but you may also be wondering about the purpose of each of these structural elements. In this article, the Crawl Pros team will review the purpose of crawl spaces vs. basements, as well as the possibility of converting a crawl space into a basement.

What is a Crawl Space?

what is a crawl space

A crawl space is a low-clearance area under a house’s floor, primarily responsible for keeping the house off the soil to control moisture levels within. As an unheated space in your home, crawl spaces typically rely on natural, non-mechanical methods of circulating airflow, such as crawl space vents, to prevent the buildup of excess moisture. Especially in wetter climates like Seattle and Portland, a properly ventilated crawl space is critical to regulating the moisture levels in your home. Too much moisture in your crawl space — and, in turn, the growth of mold and mildew — risks not only the structural integrity of the house, but also the health and wellness of its occupants.

Crawl spaces are also a place for hiding the basic utilities of a house, including heating ducts, electrical lines, water pipes, other ductwork, etc. Many of these items could also be in a basement, so, in that respect, they share a function. Crawl spaces, however, are cheaper to build than basements (saving you between $5,000–10,000), though they take approximately the same amount of time to construct.

What is a Basement?

What is a basement

Basements are livable, underground spaces — either entirely underground or partially — with concrete foundations and higher clearances.

They share some similarities to crawl spaces, namely in that they’re spaces to hide the guts of a home. Originally built for temperature-controlled storage in the form of root cellars, basements became the modern space with which we are now familiar in the 1950s as industrialization took hold. These days, the primary purpose for having a basement is to add square footage and living space to your home once the basement is finished. This makes developing a basement more expensive, as it is a larger space that requires concrete walls and floors, rather than the dirt and soil comprising the floor of a crawl space. The majority of a basement is underground, though some homes built into hills have daylight basements, meaning half of the basement is exposed.

So, What Is the Difference Between Crawl Spaces vs. Basements?

As we mentioned before, the primary difference between crawl spaces and basements is the livability. Basements are part of the livable, heated portion of the house, and — just like your living room and bedrooms — you’ll want to keep the temperature regulated for the comfort of those inside it; you can do so by properly insulating the space, and effectively sealing it off from the outside. Because they’re unventilated underground structures, however, it can be incredibly difficult to keep basements dry.

Conversely, crawl spaces are part of the non-livable, unheated portion of the house, requiring both insulation and ventilation to control the moisture levels of the space.

Another major difference between crawl spaces and basements is the clearance. Crawl spaces are 6 feet tall at the very most, while basements start at 8 feet. With crawl spaces ranging from 18 in–6 ft (the majority being around 3 feet tall) and basements ranging from 8–10 ft, this is perhaps the most apparent difference between the two spaces.

Unfinished basements are not classified as crawl spaces, though they may appear to bear some similarities. Basements can provide living space, once finished, while even the deepest crawl space will still be too shallow to be livable. Because of this, both finished and unfinished basements are often used to house heaters/furnaces, water heaters, laundry rooms, and storage. 

Crawl Space vs. Basement – What Do Most Homes in the Pacific Northwest Have?

While many older homes in the PNW have both a basement and a crawl space, newer builds are more often opting for only crawl spaces because basements are difficult to keep dry, especially in wet climates. However, some modern homes in the PNW do still build basements to gain square footage. Daylight basements have also become popular — the front access has windows, while the back access is crawl space. 


Can a Crawl Space Be Turned Into a Basement?

Perhaps you’d like more room for storage, entertaining, or even a couple of new bedrooms … but you only have a crawl space. Can your crawl space be converted into a basement? 

Short answer? Yes, but it’s gonna cost you.

Converting a crawl space into a basement is expensive and no easy feat, but it is an alternative to building an above-ground addition to the home. Building out a basement requires extensive planning and time, but the basic construction steps are as follows:


  1. Jack up the house and support by steel beams.
  2. Dig out dirt to the proper depth for the basement.
  3. Pour concrete for the subfloor and foundation walls.
  4. Set the house back on top, now with additional square footage and value added to the property. 

Crawl space conversion is a technique that has been in use for over 60 years, with conversions becoming safer and easier. However, this is not a DIY project. It will require the work of a knowledgeable and experienced contractor and engineer. Because it is a costly and time-consuming project, it’s important to consider your reasoning behind it and to eliminate alternative solutions. It is also important to consider your geographic location. If you’re in the PNW, you may want to avoid this project due to the extensive waterproofing that will be necessary to keep your basement dry and usable. 


Call Crawl Pros for Crawl Space Inspections

When it comes to crawl space ventilation, crawl space insulation, crawl space encapsulation, and everything in between, Crawl Pros is your go-to service provider. With locations across the Northwest, Crawl Pros is the regional expert in crawl space and attic services. We understand common issues with houses in the area, and can offer thorough, accurate explanations and recommendations as a result. We’re so confident in our ability, in fact, we offer a “Perfect Lifetime Guarantee” with all of our services, including water remediation services if moisture buildup has already occurred.

If you’ve got questions about your crawl space or attic, please submit the form below. We look forward to hearing from you!

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