A wall controls water, air, vapor and heat. One product does not make those jobs identical.
Repair leaks and provide flashing and drainage. Insulation is not a substitute for water management.
It needs continuous connections at joints, edges and penetrations. A missed connection can dominate the leak.
Retarder location and permeance depend on climate, indoor conditions and the assembly’s drying path.
It does not prove drainage, air continuity or vapor control. Check the whole installed layer.
For each claimed role, check its tested property, thickness, joints, substrate and connections.
Trace corners, windows, floors, roofs and service openings before covering the work.
Name all four functions and show their connections. Then choose products for those specific jobs.
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