Slab or Crawlspace for new house?

[Larry]

Basement is out due to bedrock and wife can't handle steps.

I'm leaning towards a crawlspace with block walls, and home grown joists.  Finished floor will be strip hardwood and tile.  If I'm thinking correctly the crawlspace will be the cheapest to build and easiest to install utilities but most labor intensive.

On the other hand our site is well suited for slab construction.  I poured a 30' X 50' floating slab (turned down footings) few years ago for the shop which worked great.  And the slab does have the advantage of fast construction...not important to us.

[Norm]

If I had my druthers I'd go with a slab Larry. Each has it's advantages and disadvantages but for me I'd use a concrete slab. I'd use a footing of some kind even though you probably don't have as much frost heave as we do. :D

[Raider Bill]

LArry,

How about on piers?
You could use either treated lumber set in mud, 12x12 filled blocks, or sonotubes.
Less costly than a slab, allows airflow under the house which will control moisture and makes it easy to run utilites.

[ljmathias]

We built the neighbors house on a crawl space/raised foundation- lot more expense for the below-floor part but much easier to do plumbing for.  I built my house (two story, 2000 sq ft) on a slab with stone floors- couldn't do that easily on a raised foundation.  Harder to do HVAC though.  I think you have to list all your needs and desires and balance them out: cost vs materials desired (type of flooring), type of heating (traditional forced air vs radiant heat) and so forth.  Every house should be different, designed to provide the best compromise for the people who will live in it...

I should mention, both of the above are stick built; haven't done a house with timber framing yet and that adds another dimension of complexity: SIPS or stick-built in-fill, routing HVAC, plumbing and electrical and on and on.  I LIKE the complexity of it all: a chance to learn new stuff, figure out how to adapt and extend what you learn, and coming up with a house that is totally unique and yours.

Good luck and have fun: take your time up front cause once you start the process, things have to move pretty fast to get in the dry and then finished.

Lj

[scsmith42]

Larry, one benefit of a slab is the ability to incorporate radiant heating into it.  I know that they make systems to go under wood floors too, but I think that the slab based ones work better.

Scott

[Radar67]

I've been working on my plans. I did a cost comparison on conventional versus slab. Now I have always said I would build with a conventional foundation because it was easier to get to the plumbing and such, but based on the comparision, I am going with a slab.

A 50 x 60 slab with a connected 10 x 20 slab is about $4000 cheaper than conventional (I figured the wood floor on a 5 course block wall). That is with me cutting the joists myself. (this figure is on material only)

If you decide to go with piers, use the filled block. In our area with the termite problems there is no way I would build a house on treated wood buried sub-surface, either in concrete or dirt. Sorry Raider Bill.  :

[Raider Bill]

I agree and would use either filled block or sonotube myself.
When designing the house I am building in Tenn I considered this same thing. Due to wanting a shop below my living space I went with slab but if things had been differnt I would have used concrete piers.
My friend is build a 24x36 cabin about 200 yards from my site he is using sonotubes on buried pads. Great system but some people are scared of mud.

If using slabs you need to know where your plumbing is going prior to pour. On piers you can decide later.

[FrankLad]

We pretty much had to build over a crawl space, due to not having an attic for ductwork.  As mentioned, benefits are access to plumbing, etc.  Plus I can drop and run audio/video wiring for entertainment stuff or whatever else I may do in the future.   Also, since it's a 1600 SQFT area down there, we have room to store things (although I don't like to let it get too crowded)

The outside of the blocks were sealed with some damp-proofing paint/tar and Delta-MS waterproofing over that.  The crawl space is also conditioned with the rest of the house, so there's no excessive moisture and no cold floors above.

Really, I guess you can say we have both a crawl space and a slab.  The only plumbing that goes through the slab (was in place before the slab was poured) is our septic stub-out and a very handy drain pipe (in case it ever floods) which was great during the rainy times before the roof was put on.

[Raider Bill]

Frank,

I'm curious why you slabbed your crawlspace?

[metalspinner]

My neighbors all have slabbed crawl spaces.  It's real handy for storage of all their junk. My house is the only one with a basement.  I guess the original owners of this house are the only ones that spent the extra $$$ to go all the way.  8) And I am the only one on the block who's back does not hurt pulling out the decorations each year.

Larry,
For all the future owners of your home... spend as much money as possible! :D :D :D :D

[FrankLad]

Frank,

I'm curious why you slabbed your crawlspace?

Engineer said it was primarily to keep the block wall from scooting inward over time, as the outside of the block wall is backfilled around 18" high.

[Polly]

  8)  old time log cabin builders said the first row of logs should be 18 inches above the ground to prevent termites what do you think ??? ??? 8) 

[Radar67]

All of my books on conventional foundations recommend 18 inch clearance from the bottom of the joist to the ground for the same reasons.

[Don P]

Code even  ;).

I've got both, crawl under the kitchen/plumbed side and filled w/ a slab on top for the unplumbed area. Poured a rat slab in the crawlspace. I toyed with the idea of burying 3' culvert for raceways and doing a slab over the whole thing. I will say the tile is harder on my bare flat feet than the wood floor but Scott is right about the radiant.

[moonhill]

This is my first posting here.  As more options how about a reinforced concrete beam on grade with a rubble trench.  Slabs are great but can be hard on the home keepers(wifes) feet.  Tim

[FrankLad]

Polly:   :D I remember reading a discussion on that before.

The backfill comes up 18" above the footing, but the actual distance from ground to mud sill & rim joist is around 3 feet or so.

[scgargoyle]

For totally different reasons- I've lived on a slab for 27 years now, and I'll never have another house on a slab! It's too tough on the feet and back. I read once that when they first built the Lincoln Center, a ballet troupe refused to dance there because the stage was concrete. They had to build a wood floor over it. You wouldn't think it would make much difference, but for me, it does. Then again, the dogs really like it in the summer time!

[Don_Papenburg]

A radient  heated slab is GReat.  I hate unheated concrete . 
My crawl is concrete and I dug it 7' deep so I could stand up , my knees don't like that crawling thing.