Red oak 3/4 x 3-1/4 in solid: tongue-and-groove, random lengths. Janka hardness: 1,290 lbf. Grades: Select & Better (minimal character), #1 Common (some knots), #2 Common (rustic). Finishes: prefinished (factory-applied UV-cured) or site-finished (sand + 3 coats polyurethane). Installation: nail-down on plywood subfloor (3/4 in min), 15 lb felt underlayment. Acclimate 3-5 days before install. Moisture content: 6-9% at install (within 2% of subfloor). Expansion gap: 3/4 in at walls. Cost: $4-$8/sf material, $3-$6/sf install. Refinishable 3-5 times over 75+ year lifespan. Not for below-grade or directly on concrete. CSI 09 64 16. Alternatives: white oak (1,360 Janka, more water resistant), maple (1,450), hickory (1,820).