Expanded PolyStyrene (EPS) foam board insulation is the optimal combination or performance, reliability and price for insulating PEX radiant heated concrete slabs (above and below grade). Available in two options: Standard 4ft x 8ft foam board sheets in 1", 2", 3" and 4" thickness - PEX pipe either secured directly to foam with PEX stapler and staples, or secured to the top of rebar or wire mesh (slab reinforcement), which either lays on top of or raised above the foam board. Pre-formed PEX foam board insulation with knobs for holding the PEX pipe in place. Installation does not require a stapler or staples - the pipe is simply "walked-in".
All insulation panels we sell are 2lb/cu. ft density (25 psi rating - sturdy enough to walk on) and are made in the USA.