Here's one of the top products run in PME throughout the year 2002. Warmboard is a 4 x 8 T&G structural subfloor panel with a top surface of highly conductive aluminum. Carpenters nail it directly to the floor joists in the manner of conventional platform framing. Its modular pattern of grooves link together to provide an infinite variety of radiant designs. The installer then simply presses standard 1/2" PEX tubing into the groove to complete the panel installation. Warmboard.