Radiant slab installation

Constantin

In my house, the basement layers are as follows (bottom to top): Crushed stone, vapor barrier, 2" XPS foam, PEX tubing and steel grid, concrete.

Given what a long response time concrete has due to the very high thermal mass, maintaining an even temperature is not that big of a deal. Ideally, read <a href="http://www.heatinghelp.com/shopcart/product.cfm?category=2-2">Dan Holohans primer on radiant design</a>, it's a great introduction into the proper design specs, and why to chose one over the other.

The question of how to zone the basement should be asked the other way around: Do you have reason to believe that active microzoning is necessary in the basement due to inherent conditions, like a walk-out wall on one side, etc? In my basement, the temperatures are very even, despite just having one zone controller and a simple pump&manifold.

George Durisek

Radiant Slab Installation

Does the vapor barrier on a slab on graade installation go below the slab insulation or above the slab insulation? Also, what type of control scheme for the manifolds is prefered? Constant circulation manifolds coupled with a varible speed pump for mixing or installing telestats on all the manifold loops and having thermostats open and close them as required.?