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Dry Pack question.

nibs Member Posts: 516
Have to do the shower soon, was looking at dry pack, which is new to us.
We have the pex zip tied to 4 inch wire grid, laying on insulating foam, will not attempt to raise the wire grid. Need a depth of mud about 2 to 3 inches. Can I dry pack directly onto the styrofoam, or should I pour wet cement to cover the pex, then drypack next day to give drypack a firm base? Have lots of exp with wet mud, and do not fear doing the pan with high strength fiber entrained cement.
Advice please.


  • Zman
    Zman Member Posts: 7,573
    Is the pan structural, sitting on earth, or just to create slope?
    Not sure why you wouldn't pour it wet with sand mix, mixed just stiff enough so it wont self level. You could then pull the tubing and mesh up for stronger pan and better radiation.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • nibs
    nibs Member Posts: 516
    @Zman Thanks, that is what we are gonna do, the cement is in the mixer, will leave screeds inplace until the mud is self supporting.
    Lots of experience with wet cement, but none with drypack.
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,047
    edited June 2019
    Did you water test the pan?

    Any pictures?
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • nibs
    nibs Member Posts: 516
    @Alan(CaliforniaRadiant)Forbes Not yet, still going to hit it with steel trowel later this evening. Will wet it down tomorrow as part of the curing process.
    This far North cement takes a while.