DQOTD: Do We Want A Crawl Space?

[Midpack]

We’ve had homes with full basement and full slab, but never a crawl space. Where we are looking slabs are most common but crawl spaces are second, so we may have that choice. A crawl space gives access under the home which can be good (plumbing, wiring) or bad (moisture, mold, stale air, insulation, more movement/settling?, higher cost than a slab?)? Those of you with crawl space experience in warmer climes, what say you given the choice of slab or crawl?

 

[Another Reader]

I grew up thinking slabs are inferior. They crack and move, and the plumbing is trapped and hard to repair. However, crawl spaces have problems as well. Floors move out of level as lumber ages and piers sink. It's hard to insulate as both plumbing runs and HVAC ducting are located in the crawl space. Moisture can accumulate.

I would rather have everything in conditioned space. I understand it's possible to seal crawl spaces and insulate using vapor barriers, although I have not see this personally yet.

 

[Big_Hitter]

crawl for sure - slabs crack

 

[Dash man]

Crawl spaces make remodeling much cheaper. I never had a problem, but wouldn’t choose to have one in a place with snakes.

 

[Brat]

Crawl space for almost all environments. Snakes can be dealt with.

 

[daylatedollarshort]

The housing development where we used to live all had slabs and to repair pipes some homes had to have the slabs jack-hammered.

 

[davebarnes]

Crawl space.
Concrete foundation.
Gravel floor.
Height of 5 feet plus.
You can put furnace and water heater in it.
My neighbor has his [large] gun safe in it.

 

[flintnational]

For the second time in our lives we have a slab (6 homes). And, it has been fine. We added a bathroom which required jack hammering. It was not as big a hassle as I thought it would be. I prefer a basement or crawl space for access to plumbing and wiring. I also like the elevation a crawl space gives a home. You can accomplish the same with grading and a slab, but I don't see builders do this much.


Edit to add: The slab is generally cheaper. So if cost is an issue, a slab can be an option. We wanted this particular neighborhood and all the homes are on slabs. We would do it again. No regrets.

 

[68bucks]

I would not want a slab. As mentioned it makes access to utilities a real pain. My choice would be a basement. My last 2 homes had basements one finished and one unfinished. Our current home has a crawl. If a crawl is reasonably deep (3' or more) you can get in there and work on things. I would definitely encapsulate the crawl and condition the space. A vented crawl is susceptible to moisture and mold. Ventilating crawl spaces is the old thinking of crawl space management. The best methods now involve insulating the foundation walls inside and putting down a thick vapor barrier that covers the ground and runs up the walls and all the piers, etc. with all the seams sealed. Vents, if present, are sealed up to manage the air and moisture in that space. If moisture is a problem you can dehumidify the space. There are lots of systems out there for that. There is no reason a crawl space would allow settling or movement any more than a basement. A slab is a little different but it still needs a foundation and will crack and move if not properly constructed. I don't live in a warm climate year round but ambient conditions shouldn't matter. It's been plenty hot and humid this summer so far.

 

[travelover]

This is my first house with a crawl space. The good news is all the wiring, ducts and pipes are accessible (Pacific Northwest). The bad news is that it is only two feet tall so you literally crawl around on your elbows and knees. If it was another foot taller, it wouldn't be bad at all. I've never had a house on a slab, but it seems like a bad idea to have pipes buried in concrete.

 

[ransil]

I have a crawl space, just spent 10k on 20 mil waterproof membrane, Joist reinforcement, mold removal and insulation.

House built with clay backfill to the rim joist, not slopped that well.

Crawl space did have gravel and plastic down, not 100% effective, was not sealed round 1 had coons and ground jog gain entry pulled down 12" fiberglass insulation and peed on it, insulation made nice mouse houses too.

Removed fiberglass ( nasty job) had spray foam installed.

I would prefer a basements , better place for utility's and junk.

If doing a crawl space i agree with above concrete with frence drain outside and proper fill, gutters on house all the way around dumping into a pit or some place 20 plus feet away.

 

[Bestwifeever]

We have a full basement under the main old house and a four-foot high crawl space under the family room we added to the back about thirty years ago. The family room settled and pulled away from the main house after twenty years. Big bucks to fix. You probably won't have that issue of two different foundations, and I imagine the builders in your area know what they are doing with either type of foundation.

 

[aja8888]

We have a "cable lock" foundation (slab under tension - cables through the slab). No cracks, but this is south Texas and all homes are on a concrete slab due to the high water table and the Beaumont clay under the shallow topsoil.

If I lived way north, I would probably prefer a basement that was engineered to be waterproof (good drainage, pump, etc.).

Crawl space does have many advantages, including access to plumbing, but how good would it hold up in a hurricane?

 

[Big_Hitter]

but this is south Texas and all homes are on a concrete slab due to the high water table and the Beaumont clay under the shallow topsoil.

Our house in the Houston Heights was pier and beam (crawlspace) and built in 1926. I think it's still standing today.

Kinda neat I was able to easily get under the house. Problem though is that cats love to have kittens under there.

I also know of at least one house in the Heights that has a basement; I went into it when the house was for sale.

But yes, generally almost all houses in Houston are slab.

 

[ransil]

How bout a stem wall

 

[Koolau]

I guess the first question I would ask: Who is going to do the crawling when the time comes? If it could be you, that would be one vote for a slab. At LEAST, the crawl space needs to be really deep. I had a ranch with a crawl space. I had to crawl (and I do mean crawl) the length of it in shallow water to get to the well pump/pressure tank once. Not fun, even in my 30s. Now... forget it!

Our last house had a crawl for part of the house, but it was deep enough I could almost stand up in it. Not too bad, though getting through the little access port was a bit of trick.

Oh,and if you've seen BREAKING BAD, you might also think twice about a crawl - especially with an external AND internal entry way.

Given my druthers, I'd opt for an unfinished basement - then finish it in your spare time (heh, heh.) As always, YMMV.

 

[ransil]

My crawl space is about 2 feet high yo botyom of joists with 2x12 joist.
Access is from a outside panel under the deck ( belly crawl 15 feet ) or trap door in closet. ( big guys not gonna fit)
Gravel base not good on the knees, ok to work in when needed, not creepy like some i see on hgtv remodel shows

 

[samclem]

I like having a basement, if it is dry. I have had shallow crawl spaces and prefer them to slabs, but they are a PITA as far as access. If money is an issue and a full basement isn't desired, a very good option is a conditioned crawl space with about 42 inches of headroom. The walls of the crawlspace are insulated (rigid foam boards or spray foam), the floor has thick plastic sealed to the walls, and the crawlspace is treated like a room for HVAC purposes (i.e supply register and return duct). So, the crawlspace is warm in the winter (no frozen pipes), the floors in the living area aren't cold, and the crawlspace isn't a mold incubator (it is as dry as the rest of the house). It generally costs less and is easier to do a good job of insulating the crawlspace walls than to insulate the floor of the living area. To go deluxe, a "rat slab" (approx 2" thick) can be poured on top of the plastic on the floor of the crawlspace.


Many folks retrofit their existing crawlspace to make it into a conditioned crawlspace, to gain the advantages. But it is easier to do it this way from the start.

 

[pb4uski]

I would prefer a crawl space.... I know numerous people that have them.... Mom has a basement that is ~6'... a neighbor has a 2' crawl space but with a poured concrete floor and he uses a little under-car creeper to move aound in it... a friend has a ~4' crawl space with a poured floor and uses a chair with wheels to get around rather than walk hunched over. Good access to plumbing and wiring for maintenance, repairs and changes and if it is high enough some decent storage space.

 

[Ronstar]

We have a walk out basement with living space taking up most of the basement. Great for extra space and storage.

BIL has a great setup. 1700 sf ranch . Half basement, half crawl space with concrete floor. Crawl space is about 3-4 feet making it easy to get at plumbing, etc.

 

[Hermit]

The original construction plumbers in our house in Virginia cut through a floor joist in the foyer powder room to install the toilet. The subfloor did a great job of holding up the joist. - For a couple of years. I had rotted subfloor under tile. You won't have that kind of problem with a slab. On the other hand, I don't think I would ever buy a house on a slab. Just my preference.

 

[Bamaman]

Crawl space homes just feel warmer than a slab home. Many slab homes have water pipes in the attic, and that is a potential problem on ultra cold winter nights.

I once had pipes freeze one Christmas when we were out of time. The same thing happened to thousands of homes in our city. The damage was about as bad as a burn for us all.

We have since had three houses with basements finished as nice as upstairs. They are relatively inexpensive square footage. My man-cave is 28' x 48' with 10' ceilings, and such space spoils me. I also have 2.bedrooms and 2 full bathrooms down there.

 

[mountainsoft]

The choice of foundation often depends on where you live.

If you live in a warm climate with a high water table a slab is a common option. It's relatively inexpensive to build, and you get the floor and foundation in one step. But any future repairs or alterations are difficult and expensive.

In mild climates a crawlspace is a great option. The footings go deep enough to get below the frost line and you still have access under the house to easily repair plumbing or electrical issues. We poured a 24" high stem wall on a 10" footing, giving us around 34" to crawl around under the house. Yeah, you still have to crawl, but it's not like you're under there very often. We've only lived in our house 14 years and I've already needed to crawl under to fix a leaky tub drain, run TV cables, run computer network cables, etc. We put a layer of pea gravel in our crawlspace and covered it with a 6 mil poly vapor barrier. If you're in an area where rats or other critters are a problem, you can have a thin "rat slab" poured inside the crawlspace to prevent animals from burrowing up.

In colder climates the footings have to go so deep to get below the frost line that you might as well have a full basement. It's essentially a crawlspace, tall enough to walk around in. Of course, if you have a high water table or soil that doesn't drain well, keeping water out of a basement can be tricky. It's doable, but it takes a lot of preparation to keep a basement dry.

If you build in a remote area with limited access, or an area prone to flooding, a post and beam foundation may be a smarter choice.

There's no one size fits all solution. You have to evaluate the conditions where you live. In my area (Washington State) crawlspaces are the most common and that's what we chose as well. A full basement would have offered additional living space, but the cost and complexity would have been much more involved.

For small buildings like our shed and pump house, I just poured a simple slab foundation. They don't weigh much and the whole structure can move up and down with frost.

 

[mountainsoft]

Those of you with crawl space experience in warmer climes, what say you given the choice of slab or crawl?

Another thing to consider is whether Radon is an issue in your area. If so a crawlspace would be much easier to ventilate than a slab.