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Insulating upper level floors? - ken

Ken Member Posts: 26
The books talk about insulating between the upper floor (which is heated by pex in a one and a half inch concrete) and the floor below it. Is this normally done or only if your water temperatures in the upper floors are very high.


  • Dave Holdorf
    Dave Holdorf Member Posts: 12
    Insulation between floors

    You should always insulate between floors when the upper floor is radiantly heated.

    The typical rule of thumb for insulation below radiant is 5 times the R-value of what above the radiant system. For example, radiant tubes in a mud floor with tile has an approximate R-value of .5. A 3/4" plywood deck below has an R-value of .8. With this rule of thumb, the below R-value should be around 2.5 and just one sheet of plywood falls short.

    It doesn't have anything to do with high water temps. Sure higher temp will deliver more heat to the ceiling, but to get the most out of the radiant system, use insulation.

    Dave H
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