Thermal Bridging at Metal Helical Piers with Metal Brackets
Have an elevated floor (22′ x 32′) on piers due to existing mature trees. The piers are metal/helical screw with metal brackets – corner brackets are bigger (10″x10″ or so) as they join two beams. The floor is flash and batt, with foam sprayed from above onto pressure-treated plywood covering entire underside. Floor joist are pressure-treated as well. Above is OSB with 3/4 composite plywood/white oak (10.5″ width). In winter, the corners of the floor are colder due to geometry/physics (surface to volume) and I’m thinking thermal bridging due to the metal brackets. The metal brackets are exposed underneath – brackets inset from plywood as they are in direct contact with support beams. Looking to use foam board at about 18″x18″ square glued and sealed around edges at the brackets and elastomeric 3.5″ ID pipe insulation (3/4 in wall) on the metal pier posts rising to abut the foam board. Looking to reduce heat flow to get a couple of degrees reduction in temperature differential between center of floor and corner. If anyone has insulated metal helical screw piers/combated bridging, would like to hear.
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