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Community and Q&A

Slab vs. crawl space

Mike Koness | Posted in Energy Efficiency and Durability on

Hello. I seem to have written my question incorrectly previously. I am preparing to build a 1,300 sq. ft. home in northwest Montana.

Around here crawlspaces and basements are the norm. I am researching using block frost walls (no basement) and a slab. Most of my builder friends are counseling me against this.

I want to have some wood floors and some tile. Wood floor area would be poured at a lower elevation. I would lay down treated sleepers and plywood to attach the 3/4 flooring to.

Does anyone have any good information to layout a pro and cons list? The alternative is ICF frost wall with top of joists set 1 1/2 above top of the ICFs.


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  1. User avatar
    Sean Cotter | | #1

    Not sure if you need a subscription (I have one) but Journal of Light Construction has an article this month with a slab on grade project then a floating floor over EPS. It looked rather ingenious.

    Why are the locals against your idea? Lack of experience?

  2. Steve Knapp CZ 3A Georgia | | #2

    You can install engineered flooring over a slab—especially if you insulate the slab and slope the grade away from the home. That said, you usually don’t want to force your builder and subs out of their comfort zone.

  3. User avatar GBA Editor
    Martin Holladay | | #3

    As long as your slab is above grade, you can install any kind of flooring you want above a slab. Flooring manufacturers provide installation instructions. You and your builder can do some online research to figure out the requirements for flooring installation.

    For example, here is information from the American Hardwood Information Center: .

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