Replies

1. 
   Guest_ | Feb 17, 1999 11:02am | #1

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   Greetings David

   Question, what is the purpose of the 5/8 stone mixed into the self leveling material, I'm assuming Gypcrete or such material is used. I believe that you are installing this over an existing slab. Is there a problem with the old slab?

   Gabe Martel GSC
   Project Manager

1. 
   Guest_ | Feb 17, 1999 06:17pm | #2

   *No, I think the 5/8" stone material is the floor covering to be installed over the Gypcrete. Since the stone is 5/8" and the maximum floor thickness (for whatever reason) is 1 1/2", there is only room for 7/8" thickness of Gypcrete.The question is:Is 7/8" enough Gypcrete to cover the 5/8" PEX?Rich Beckman

2. 
   David_Nickelson | Feb 17, 1999 07:25pm | #3

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   Yes...Rich...that is the question...I also...need a minimum of 1/8 " thinset...
   There is no problem with the old slab...my concern..is the coverage over the PEX tubing..and cracking at the tubing lines.

   DN

3. 
   David_Nickelson | Feb 17, 1999 09:06pm | #4

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   A client wants to install radiant heat over existing slab. PEX tubing is 5/8".
   Our selected stone material...is also 5/8" and my max thickness allowable is 1 1/2 " What is the minimum coverage over the PEX [from field experience] allowable to the bottom of the stone material??

   I am posing this question to the installers...but I would like some industry feedback...Thanks... DN

4. 
   Guest_ | Feb 17, 1999 09:06pm | #5

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   Greetings again David

   A good rule of thumb is 2 x the thickness of what you want to cover.

   If the outside Diameter of you pipe is 5/8 then you should have 10/8 or 1 1/4 inches of Gypcrete.

   The likelyhood of cracking is still high. The astringent in any high moistured floor levelers will work at different rates over the different thicknesses. Any area that is displaced by your piping will dry faster than clear areas. This will cause minute cracking.

   We have stopped using Gypcrete on most of our commercial application and have been studying alternatives. Gypcrete should have been the answer to most of the leveling problems that we encountered in ICI but due to it's slow drying in the last stages, moisture was always trapped by any of the sheet floor coverings and failure did and continue to occur on sites that are several years old.

   In residential applications, as long as you respect it's limitations,(Manufacturers Rec.)it still make a reasonable base to work from.

   Don't know if I was much help

   Gabe Martel GSC
   Project Manager