Concrete Slab subfloor vs. Wood Joist and Wood subfloor

[Southern Steve]

If this has been covered before, I apologize in advance.  But I didn't see it directly mentioned in the search I did.

Am downsizing, looking to build  around 800 Sq Ft. House. I have seen several installations on this site where Radiant hot water heat was used in a concrete slab subfloor/floor.  Since this area ( southern Indiana) also requires AC in summer - for the humidity if not the temperature - and thereby I would have to have an air handling unit anyway, I am not going to do the radiant heat thing.  However, my question is, does anyone have any experience with poured slab floors in terms of "sweating" in high humidity times?  If so, can this be avoided and how?  Does one insulate somehow between the grade and the concrete pour?  Can a wood finished floor, or carpet, or tile, or laminate be used sucessfully on a poured Concrete slab subfloor?

Thanks in advance!

[MushCreek]

Having lived on a concrete slab for the last 30 years, I hope to never live on one again! They are cheap and durable, but they are also cold, hard on the knees and feet, and anything you drop is broken- period. There's a reason professional dancers won't dance on a concrete stage. I think properly insulated, you could eliminate the cold thing, and maybe the sweating as well. There's an article in this months Journal of Light Construction about building an insulated slab. Here in FL, when we get hot humid weather right after cold weather, the floors sweat like crazy, I suppose if we kept the windows shut and the heat on like good citizens, we could avoid it, but I like my windows open whenever possible. Another issue is plumbing. Your pipes are going to have to run under the slab- at least some of them, anyhow. If you ever have a plumbing problem or want to move something, you have to cut up the concrete floor, move the pipe, and repair the floor. That's certainly a lot harder than just going down in the basement. Here in FL, they put all types of flooring over concrete, with the tile and carpet being the most prevalent. You can do wood as well- I think they put down a vapor barrier. I put in a Pergo-type floor in one room, and it's held up well for years. It's floating on a thin layer of foam, and is undersized so it doesn't buckle in humid weather. It's not fastened at all- just the molding around the edges.

[Southern Steve]

thanks Mush.........I had thought of most of your advice, with the exception of concrete being hard on the leg joints and feet.  At my age, that is a consideration.

[builderboy]

I have a hot h2o heated slab in Eastern Canada. It's insulated with 2" extruded foam under the slab and around the perimiter. My wife love's the warm concrete for her arthritic feet. We use footwear with cork footbeads to deal with the hardness (think Birkinstock) and MushCreek is right. You drop it -it breaks. I did DIY acid stain finish which looks awesome and cleans easy (no seams for that spilt beer to ooze into.) I'd do it again if building.