Slab vs. Crawl vs. Basement

Slab on Grade(SG) vs. Crawlspace vs. Basement

SG has little to no foundation wall; basement has foundation walls; do homes with crawlspaces, and no basement, have foundation walls or is the dwelling supported by posts and footings only?

From a person who has lived to more than 19 different homes, in several states, has never lived in a home with a basement. Majority of them were slab on grade. ← is SG more uncommon??

more info, the better

Asking for a friend.

addition: Minnesota loves their basements; Oregon loves their crawlspaces; What do other States or regions of the country typically have for foundations?

Mostly foundation walls (footing and 3 or more block high, is typical)…around here anyway.

Edit: We have mostly basements. I was answering his crawl space question.


It’s a regional thing. In Minnesota, we love our basements.
Typically, I see 95% Basements, 3% Basements w/crawlspaces, 1% Crawlspaces, 1% Slab-on-grade.
The primary reason for basements with crawlspaces are due to additions being added on, thus a crawlspace.


Typically four

Materials used will vary.
(Truthfully, I didn’t fully understand the question)


The concept of a basement with a crawlspace is, admittedly, difficult to picture. Seems odd


No worries. I’m still contemplating whether or not I worded my question correctly. I ask myself one question, and it leads me to asking more questions.


Just envision a portion of a home built on a basement and another section on crawl, such as a wing or kitchen.

Or, in some instances, you have a crawl with a dug out basement. But, that’s another story.

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I thought I learned years ago that frost depth played a role in foundation depth and that is why there are so many basements in cold areas - aside from added benefit of a pit for all the water to run into, of course. :slight_smile:

I’ve done most of my inspecting in Oregon and wow, do we love our crawl spaces! I just love talking with inspectors at conferences from southern areas and you guys don’t even own coveralls! Slab, slab, slab. That must be nice… lol.

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In Tennessee it seemed most homes had crawlspaces; Florida, of course with the water table, it was all slab, unless you built your home on stilts; Here in Hawaii, it all depends on whose ancestors are buried in the soil.

I think I get what you’re saying here: (correct me if I’m wrong, please)

These four: slab, crawl, basement, pier, they each use different foundation systems.

I witnessed an array of different building components over the years - father is a carpenter, step-father was a general contractor. Though, I’ve seen next to nothing regarding the foundation of a home.

This was taken straight out of the InterNACHI’s Structural Issues course:

“The structural portion of a home inspection is perhaps the single most important part. A house’s structural integrity is often the issue of the greatest interest to home-buying clients. If the home is structurally unsound, not much else matters.”

I just wanna make sure I REALLY understand this stuff

Makes sense. I don’t imagine this is normal to see. Perhaps with older homes compared to newer ones?

It occurs fairly often. Many times it is just as Brian said. the original home had a basement or cellar and additions over the years were built beside it with crawl spaces. In any case; slab, basement or crawl, the foundation will be extended BELOW the frost line for that region.


You know, I think I might have seen this. The property had an odd slope that the house sat on. Had a basement, but homeowner extended the back of the house and created a small platform with a crawlspace. Not a walk-out basement, btw.

And thank you guys! You’ve helped me to ask myself better questions


Hahahaha So true! I’ve gone into a few crawlspaces here in Hawaii. But of course, we’re just a giant rock. So much of Florida is practically low wetlands - dig three feet and you got water baby!

There are many configurations. Technically, a foundation is the load bearing portion of the structure which transfers the load to the ground.

A crawlspace is nothing more than an uninhabitable plenum between the floor structure and the earth. A home built on piers may have a crawlspace whereas the perimeter is non-load bearing partition walls between piers. And a home on a crawl may have a combination of piers or columns and load bearing walls.

Here are a couple of photos of a home with a basement/crawlspace combo


Yeah! Wow! So they had a point-of-entry for the crawl in the basement?

I love visual aids. God bless 'em.

Yes, and that crawl had many issues all jammed into a small space. And the front basement CMU block wall had cracking/bowing due to soil pressure. Typical flip house that looks great but is nothing more than lipstick on a pig.


North Carolina reporting here. According to the local inspectors we’ve sold to, they’ve said it’s a majority of crawlspaces in central NC (which is really fun, what with the snakes and spiders around here). After that, slabs are more common and basements are pretty rare.

As for my own experience I’ve personally lived in around 10 different homes in NC and all but one of them had crawlspaces. I did notice that in the mountains you have a better chance of seeing basements or the basement/crawlspace combo.