Glossary / fire-retardant-treated wood

fire-retardant-treated wood

Wood treated to reduce flame spread, often listed as exterior FRT. Oregon R327 names it as one walking-surface path. It is not noncombustible and not a coating.

Last verified 2026-08-23. JSON (CC BY 4.0)

Also called: FRT wood, exterior FRT.

Do not use as a synonym: fireproof wood.

Related

• ignition resistant
• noncombustible
• decking
• sfm-12-7a-4
• Spray-applied FRT and special inspection

Where this term is used

4 guides use this term.

• Deck railings in the WUI
• Exterior FRT wood and weathering
• Spray-applied FRT and special inspection
• The 200 square foot 2-inch lumber deck exception