What is the best method to install pex over existing floor?

ap

We are renovating and putting on an addition to a church.  We are installing infloor heating in the addition and would like to put it over the existing concrete floor.  We would like to find the most cost effective way to do this and am constrained by having to keep the floor as low as possible.  Any one have any suggestions?  Thanks

Alan (California Radiant) Forbes

Tough Call

Cost effective AND as low as possible?  The problem is that you have to somehow prevent the existing slab from being heated where it will be of no use.



We used to install one inch of rigid insulation on top of the existing slab, then tie PEX tubing onto welded wire mesh and then a 1-3/8" overpour of Gypcrete - see photo.  But then new products came on the market like Thermalboard and QuikTrak that are 5/8" and 1/2" respectively.  These are manufactured wood products that can be placed on an existing floor that have grooves to accept the tubing.  Additional plywood and a thermal barrier may be necessary.



More information is here:



http://www.thermalboard.info/appinstguide.html



http://www.doyouuponor.com/~/media/Extranet/Files/manuals/QuikTrak_InsG_9-00.aspx?sc_lang=en

NRT_Rob

Depends

is the existing concrete insulated?



if not, Roth panel is the lowest profile including insulation. with 1/2" pipe, your total profile is 1" thick.



If it is insulated underneath and on the edges, then you could use any panel method. quik trak/climatepanel is the thinnest but challenging in a large space (tiny pipe). assuming you want a 1/2" pipe I would recommend warmboard-R for performance or a site built "sandwich" of plywood/plates for material cost optimization if you're using volunteer labor.