Something Interesting On Types Of Foundations Here (hardwood floors, house)

[SP2SCV]

I was doing a lot of research on the types of foundations used here:

• Full basement (rare)
• Crawl Space
• Slab on grade

My assumption was that slab on grade was somehow lower quality and I have found out I was completey wrong. As it turns out, due to the large quantity of clay in central NC, full basement and crawl space foundations are not ideal. The clay absorbs water and expands up against the wall of these types of foundations, until the walls shift and possibly buckle. The slab on grade is made of reinforced concrete and meant to float in one piece with the movement of the earth, resulting in a much more stable foundation.

Thought people may want to know this, as I would never have thought that was the case.

[CaliBoy]

We have a brick foundation with a crawlspace. On a slight incline, I can stand up for a quarter of the space, but crawl for the rest. Easy to access pipes, wiring etc. Our home is also eighty years old. It's holding up well enough. Some leaks on a few sides that I'd like to repair. A small portion of the foundation needs a complete overhaul (looking to find someone great to repair this). We also have some floor levelers installed too.

Being on clay took some getting used to since we're from the west coast. I'm accustomed to expansion and contraction now and the cracks that come with it. I don't like it still, but I understand that this happens. Though I like the crawl space for access, I'm used to slab since a lot of homes on the west coast are built on slab. I do like how solid the floor feels with slab... our floors creek in various areas (hardwood floors I guess do this in an eighty year old home... well, at least ours).

[saturnfan]

We have slab foundations in our complex and the soil has sunk causing many out of plumb areas in 9 years.

The soil here really needs pilings for stability as is done in Louisiana.

[ljd1010]

Good post, thank you. We are coming from RI where all homes have full basements. Your info helps put things in perspective. I have to admit, I somehow thought of slabs as inferior.

[SP2SCV]

Originally Posted by ljd1010

I have to admit, I somehow thought of slabs as inferior.

Yes, so did I. I had listened to some family members from up north who would say that slabs where cheap and inferior, so I actually tried to stay away from them. But as I found with many things, sometimes people just say what they think, not what they know. Now that I fully understand how the slab on grade foundation works, it actually makes sense that they would be stronger and more stable.

[wanderintonc]

I lived in my first house in CT for 10 years-it was a 'cheap' house on a slab. Everyone was like, you don't have a basement? It's rare for here. We had no problems with the slab and the house is over 30 years old.

Next, two years ago we rented a house with a full basement-a typical 1950's ranch. Ugh. It smelled and some things I stored down there got mildewy. And that basement was 'finished' and considered living space! After that experience, I have decided that when we get to the Triangle, we will not persue a home with a basement-they aren't all that great. In fact, I was just at my parents' house (also here in CT) yesterday and with the rain we've had, they have standing water in their basement, all around their brand new furnace!

So for me, it will be slab or crawlspace. Basements are overrated IMO.

[southward bound]

Originally Posted by CaliBoy

... our floors creek in various areas (hardwood floors I guess do this in an eighty year old home... well, at least ours).

How about creaky floors in a house not even 5 years old? There wasn't a creak anywhere when we bought the house in 2006. Is this due to the shifting that you all are talking about and, if so, will the creaks periodically go away?

[NewUser]

Originally Posted by SP2SCV

My assumption was that slab on grade was somehow lower quality and I have found out I was completey wrong. As it turns out, due to the large quantity of clay in central NC, full basement and crawl space foundations are not ideal. The clay absorbs water and expands up against the wall of these types of foundations, until the walls shift and possibly buckle. The slab on grade is made of reinforced concrete and meant to float in one piece with the movement of the earth, resulting in a much more stable foundation.

No new news here for me. Just moved here from TX where EVERYTHING is built on a slab because of the clay soil -- from a $200K house up to a $2M house.

The clay absorbs water and expands. Then you have long periods of no rain and it contracts. The slab foundation handles this best ......BUT......any person in TX who owns a house knows to keep the soil around the foundation wet. Yes, we point our gutter downspouts towards the foundation and we have automatic sprinklers to keep the soil moist in the summer. This lessens the possiblity of large shifts occurring, which may crack the slab.

[sunnie741]

Anyone know anything about sealed crawl spaces? I guess these are more energy efficient and the builder keeps raving about them.

[alice_61]

Advanced Energy is one of the leading researchers of sealed crawl spaces. They make sense to me if you are going with a crawl space.