When building a new residential home with a monolithic slab on grade (footer and slab are poured at the same time), should any water proofing, insulating or drainage be added besides the vapor barrier?

With basement walls, there is drain pipe installed where the basement wall meets the footer to reduce hydro-static pressure buildup that can cause basement water seepage. The wall is also tarred or covered in some other waterproofing material, and foam insulation board is often added before back filling the dirt.

What, if any, of these things should be done with monolithic slabs? Does anything need to be done to terminate the vapor barrier where it comes up the outside of the footer? Should any waterproofing or insulation be done to the slab edges before back-filling? Is there ever a reason for a french drain or other draining techniques?

  • Can you give us a hint about the general location and its winter climate? If the frost line is 48 inches deep, your answer will be different from one where it "never" freezes. Also, your local codes may determine things based upon your specific soil type.
    – Upnorth
    Sep 28 '17 at 5:12
  • It's in the northern Georgia mountain area. Code requires 16" footers below existing grade, and 6" of concrete between final grade and any wood, so probably about 24" of total thickness on the outside of the foundation (with 6"-8" above final grade), and 4" thickness in the slab part over 4" of gravel.
    – Nick
    Sep 28 '17 at 5:58

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