Wood is a combustible material that will burn when exposed to fire. Fire retardant treated lumber and plywood are pressure impregnated with fire retardant chemicals that go deep into the wood, not just on the surface. These chemicals slow the spread of flames and encourage the development of a char layer on the surface which insulates the wood below and slows fire growth. This process is designed to slow down the spread of flame and reduce smoke development because of fire, to give building occupants more time to escape. Fire retardant treated lumber and plywood must be specified based on end use, whether for interior or exterior, as the treatment process varies depending on end use. Interior use is limited to applications not exposed to weather or wetting.
Floor joists, floor sheathing, partition walls, plywood sheathing, rafters, roof trusses, sill plate, sub flooring, studs, wall sheathing, 1 & 2 Hour Wall Assemblies
Douglas-fir, Hem fir, Southern Yellow Pine, Spruce-Pine-Fir
Clear. Typically a red dye is added to the solution to distinguish it from untreated wood
Please see Resources/SDS for additional information about fire retardant treated products.