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gypcrete shrinkage?

Gasper
Gasper Member Posts: 148
in THE MAIN WALL
I'm installing a thin slab gypcrete pour over tubing.  I am installing 2' x3' sleepers first between the tubing.  Then I was going to put down a 3/8" plywood (cut into 4' x 4's, with a 1/4" gap between sheets and wall edges) on top of the gypcrete.  Then finish with a 3/8" quartersawn cherry wood floor (5" wide).  Does anyone have any suggestions on how to avoid any shrinkage from the gypcrete?  I believe it will be a Maxon product.   

Comments

  • Mark Eatherton
    Mark Eatherton Member Posts: 5,852
    Run it by Maxxon...

    Can't say as I've ever seen any signs of shrinkage. I have seen it get wet and go back into tis semi solidus/liquidus state, but have never had an occasion to check it for shrinkage.



    Tell them your application and see what they have to say.



    http://www.maxxon.com/gyp-crete/data



    ME

    There was an error rendering this rich post.

  • icesailor
    icesailor Member Posts: 7,265
    Shrinkage:

    I'd be less worried about Gypcrete shrinkage and more about the quarter sawn 3/8" cherry shrinking and splitting.
  • TMorg
    TMorg Member Posts: 23
    gypcrete shrinkage

    I assume you are referring to shrinkage when first applied. The shrinkage is in direct proportion to how wet it is when applied. Less water equals less shrinkage. If the installing contractor pour a stiff mix it will not shrink much at all. We used to use a squeegie to draw across the sleepers when pouring the gyp. This helps to clean off the top of the sleepers and keep the gyp just below the top of the sleepers. Good luck. If the gyp ends up above the height of the sleepers you will need to use a floor sander to knock down the gyp.  
  • Gasper
    Gasper Member Posts: 148
    cherry wood and shrinkage

    Thanks all.  I was also told if the gyp is slightly under I could sand the top of the sleepers.  I think the better contact the better heat transfer?  Even a 1/8" gap is still a gap.....or doesn't it matter that much?

    I'm learning there is a American cherry wood and also a Brazilian cherry wood.  Cherry is supposed to be very stable, and one of these is better then the other.  I'm going off information obtained from different sites and also from a MI company Launstein Floors.  They actually test the different woods over radiant, in their test labs.  Check out their web site.
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