building sciences 1 2 3 Photo 1: Waterproof Membrane. A waterproof membrane going down on the top of a structural deck. In “Joe Speak” this is the water control layer. It is also the air control layer and the vapor control layer. Photo 2: Thermal Control Layer. Over the top of the waterproof membrane goes the rigid insulation—the thermal control layer. This insulation layer is typically extruded polystyrene (XPS). In this particular example the lower drainage gap is created by grooves in the underside of the rigid insulation. Neat, eh? Photo 3: Filter Fabric and Pedestals. Over top of the rigid insulation goes a filter fabric and pedestals to hold the traffic layer. In this particular example we have stone pavers. Photo 4: Layers Working Together. The rigid insulation, the filter fabric, the pedestals and the stone pavers. Photo 5: Finished Deck Assembly. Looks normal. And it works. 4 5 ing together—the rigid insulation, the filter fabric, the pedestals and the stone pavers. Photo 5 shows the finished deck assembly. Looks normal. And it works. Let’s go back to the rainwater control stuff for a little bit. Now that everyone thinks all of this is pretty easy it is time for a few curves. Let’s go to Florida because a lot of what I am going to talk about now happens there. Photo 6 shows a waterproof membrane installed on a structural deck. This is good. Note ashrae.org March 2011 the air control layer and the vapor control layer. Over the top of this goes the rigid insulation—the thermal control layer. This insulation layer is typically extruded polystyrene (XPS) (Photo 2). In this particular example the lower drainage gap is created by grooves in the underside of the rigid insulation. Neat eh? Over top of the rigid insulation goes a filter fabric and pedestals to hold the traffic layer (Photo 3). In this particular example, we have stone pavers. Photo 4 shows the layers work64 ASHRAE Journal