COLUMN BUILDING SCIENCES FIGURE 7 Pier Foundation. Pier foundations must keep air and vapor out of the floor framing/floor assembly. The underside of the rigid insulation on the underside of the pier foundation floor framing must be connected through the perimeter rim joist area to the exterior wall assembly. Two Layers of 2 in. Rigid Insulation Asphalt Shingles Roofing Membrane Roof Sheathing Building Paper or House Wrap Roof Sheathing Spray Foam Uninsulated Framing Fiber Cement Siding 1×4 Furring Rigid Insulation (Taped or Sealed Joints) Non-Paper Faced Exterior Gypsum Sheathing, Treated Plywood or Treated Oriented Strand Board (OSB) Weep Screed-Closure Pier Foundation Non-Paper Faced Gypsum Board With Semipermeable (Latex) Paint; Help Up From Slab Sealant, Adhesive or Gasket Sill Gasket Polyethylene Rigid Insulation (Taped or Sealed Joints) Concrete Footing installed in the frame wall cavities. Again, all surfaces should be coated/painted with acrylic latex paint including interior wall framing prior to installation of interior gypsum board. The spray foam should not completely fill the frame wall cavities, thereby providing an air space that facilitates drying after a flood event. Again, wetted gypsum board should be considered " sacrificial, " in that it cannot be readily cleaned, sanitized and dried after wetting. After a flood event wetted gypsum board should be cut away from wall assemblies above the wetting line. The air gap behind the remaining upper level of gypsum board allows for air circulation and drying of the remaining surfaces. Pier foundations must keep air and vapor out of the floor framing/floor assembly. Figure 6 and Figure 7 illustrate perimeter details-connecting the underside of the rigid insulation on the underside of the pier foundation 52 ASHRAE JOURNAL ashrae.org J U LY 2021 floor framing through the perimeter rim joist area to the exterior wall assembly. Pest and insect control is provided by installing a protection board over the underside of the rigid insulation. Fiber cement or cellular PVC boards work well in this regard. The fiber cement or cellular PVC boards should be installed using screws to allow for removal should flood waters rise above the floor framing-level wetting cavities. The removal of the fiber cement or cellular PVC boards and rigid insulation and cavity insulation facilitates cleaning and decontamination of framing members. The rigid insulation should be considered " sacrificial " if wetted by flood waters. No fibrous or batt insulation is installed in wall cavities or floor framing cavities to further reduce risk of moisture damage arising from flood waters. If closed-cell, high-density spray foam is used in wall or floor framing cavities, it still will need its exposed surfaces to be cleaned even though it is water resistant. Figure 8 illustrates the use of an elevated concrete floor used in conjunction with concrete piers. The concrete floor is insulated on the top surface to reduce thermal bridging as well as to further reduce risk of moisture damage arising from flood waters. FIGURE 8 Elevated Concrete Floor. The concrete floor is used in conjunction with concrete piers. The concrete floor is insulated on the top surface to reduce thermal bridging as well as to further reduce risk of moisture damage arising from flood waters. Subfloor 2×4 Capillary Break 1.5 in. Rigid Insulation Concrete Post Plate Under Load-Bearing Walls Only Concrete Floorhttp://www.ashrae.org