COLUMN BUILDING SCIENCES " Hat " Channel Long Screw Continuous Exterior Insulation Continuous Exterior Insulation Steel Stud Exterior Gypsum Sheathing Continuous Exterior Insulation FIGURE 7 Horizontal Girts. Adding horizontal girts increases rigidity and provides increased flexibility for cladding types. Substrate Deformed Position of Fastener Compressive " Strut " FIGURE 5 (Top) Hat Channels. Hat channels can be used with long screws to provide cladding attachment. Not much conductivity with only the screw passing through the exterior continuous insulation. FIGURE 6 (Bottom) More Hat Channels. Long screws used as a thermal break. strength of the continuous insulation and weight of the cladding and is typically calculated using a truss analogy (Figure 8 and Figure 9). The model codes now provide guidance on screw spacing and cladding weights. How about that-using long screws help keep us from screwing up exterior continuous insulation. That was easy. Are we done? Nope, now comes the really hard part. Thermal Bridging at Relieving Angles and Lintels Brick veneer construction that typically relies on relieving angles and lintels for structural support often has the most significant thermal bridging issues. Yes, yes we were here before ( " Thermal Bridge Redux, " ASHRAE Journal, July 2012), but we need to remind everyone again because we aren't dealing with it in any major way yet. Figure 10 shows three typical approaches to brick veneer 44 ASHRAE JOURNAL ashrae.o rg J A N U A RY 2022 Gravity Load of Cladding δy Geometry δ× Tension Force Compression FIGURE 8 (Top) Hat Channel Geometry. The geometry of the hat channel and the screw depends on the on the compressive strength of the continuous insulation and weight of the cladding. FIGURE 9 (Bottom) Truss Analogy. The model codes' guidance on screw spacing and cladding weights is typically calculated using a truss analogy. construction ranging from significant thermal bridging to little thermal bridging. Typical steel stud construction on a concrete frame with relieving angles welded to slab Gravityhttp://ashrae.org