We are rebuilding many small buildings (Not Houses) that were flood damaged by Hurricane Irma and have a small probability of flooding again. They are 2″x4″ framed walls, sheathed with 1/2″ plywood, covered with #15 building paper or house wrap and sided with vinyl or cement board. Remediation work included removing all wet drywall and fiberglass insulation, cleaning and disinfecting the wall cavity, and drying the framing lumber and sheathing to a moisture content of 8% or less. The flooding was short duration (Less than 24 hours) and was uncontaminated lake water so the framing, sheathing, and siding were undamaged. When we rebuild the walls what insulation would you recommend? We have considered closed cell spray foam, closed cell block foam, and rock wool bats. If we use a non porous insulation and a water proof wall covering (PVC trim board, etc.) would it eliminate the need to tear out the wall covering and insulation if another clean water flood occurred? Would a wall assembly like this dry to the outside or should we still open the wall. Thanks for your opinion.
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