Quick Specs
Common Name(s): Red oak
Scientific Name: Quercus rubra
Distribution: Northeastern United States and Southeastern Canada
Tree Size: 80-115 ft (25-35 m) tall,
3-6 ft (1-2 m) trunk diameter
Average Dried Weight: 43.8 lbs/ft3 (700 kg/m3)
Specific Gravity (Basic, 12% MC): 0.56, 0.7
Janka Hardness: 1,220 lbf (5,430 N)
Modulus of Rupture: 14,380 lbf/in2 (99.2 MPa)
Elastic Modulus: 1,761,000 lbf/in2 (12.14 GPa)
Crushing Strength: 6,780 lbf/in2 (46.8 MPa)
Shrinkage: Radial: 4%, Tangential: 8.6%,
Volumetric: 13.7%, T/R Ratio: 2.2
Red Oak Solid Wood Flooring Grades
NWFA-NOFMA CLEAR: A flooring product of mostly heartwood with a minimum number of character marks and
discoloration, providing a uniform appearance while allowing for all heartwood natural color variations.
Will admit the following: 3/8″ (.3750”) (9.53 mm) wide bright sapwood entire length of the piece or equivalent if not more than 1″ (25.4 mm) wide for 1/3 the length of piece; small burls and fine pin worm holes; and equivalent
characters such as small tight checks; in the absence of these, one thin brown streak 3″ (76.2 mm) long to be allowed every 6′ (1828.8 mm) of piece.
NWFA-NOFMA SELECT OAK: A flooring product with coloration variations produced by differences of natural
heartwood and sapwood, along with characters described.
The face may contain: unlimited sound sapwood; slight imperfections in milling; one (1) small tight knot every 3′
(914.4 mm) of piece; pin worm holes; burls and a reasonable amount of slightly open checks. Brown streaks should
not extend the entire length of a piece. Two (2) flag worm holes to every 8′ (2438.4 mm) of the piece are permitted. Slight imperfections in face work (torn grain) admitted. An intermittent, brown machine burn across the face not exceeding 1/4″ (.250”) (6.35 mm) in width admitted. Also, a slight quantity of bark on the back or sides admitted. Will admit pieces with one-half (1/2) tongue, full length of the piece. Spot filling is generally required for open characters.
NWFA-NOFMA NO. 1 COMMON OAK: A flooring product which contains prominent variations in coloration and
varying characters.
The following are not admitted: broken knots over 1/2″ (.500”) (12.7 mm) in diameter, large grub worm holes; and
splits extending through the piece. Open characters such as checks and knot holes are admitted, but must be sound and readily fill. Not more than 20″ (508 mm) scant stock in thickness allowed to every 5′ (1524 mm) of length. Minor imperfections in machining permitted. Shall admit sticker stain; varying wood characteristics, such as flag worm holes, heavy streaks, checks, and worm holes; and an occasional dark machine burn across the face not exceeding 1/2″ (.500”) (12.7 mm) wide, 1/64″ (.0156”) (.40 mm) deep and not more than two (2) to every 3’ (914.4 mm) of length admitted. One-quarter (1/4) tongue, full length of the piece admitted. Extremely dark pieces are not to be included.
NWFA-NOFMA NO. 2 COMMON OAK: May contain sound natural variations of the forest product and manufacturing imperfections. The purpose of this grade is to furnish a floor suitable for homes, general utility use, or where character marks and contrasting appearance is desired.
The following are not admitted: shattered or rotten ends, large broken knots, excessive bad millwork, shake,
advanced rot, and similar unsound defects. Dark machine burns exceeding 3/64″ (.0469”) (1.19 mm) deep not
admitted. Knot holes and open characters which will readily fill are admitted. Occasional scant thickness (hit or miss) on the back of the flooring board the entire length of the piece admitted, providing there is full bearing across the board at some point within three inches of the ends. A limited number of pieces with no tongue admitted.