Wood Flooring Grades, Cuts & Construction

 
Wood Floor Cuts & Grading for solid unfinished hardwood strip and plank flooring in
 Ash, Beech, Birch, Hard Maple, Hickory/Pecan, Oak, and Prefinished Oak

  Clear, Select, # 1 Common, and # 2 Common

NOFMA: The Wood Flooring Manufacturers Association's principal function has been to formulate and administer industry standards on hardwood flooring. Establishing grading rules for flooring is a major part of these standards. Prior to November, 1999, these Official Flooring Grading Rules covered the standards and grades for solid unfinished hardwood strip and plank flooring in Oak, Beech, Birch, Hard Maple, Hickory/Pecan, Ash, and Prefinished Oak. In January, 1999,NOFMA began a program for certification of Engineered Flooring products. The program involved establishing grading rules for engineered flooring. These new engineered grading standards have now been incorporated in the Official Flooring Grading Rules.

For over a half-century, NOFMA has been the “Voice of Authority” in the hardwood flooring industry, extending even to U. S. Government agencies. In 1966, the Department of Commerce, the National Bureau of Standards, FHA and VA withdrew product standard CS56-60, strip oak flooring, and accepted the NOFMA Official Flooring Grading Rules as the standard for the industry.

 

 

NOFMA CLEAR OAK
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" bright sapwood entire length of strip or equivalent if not extending further than 1" for 1/3 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" long to be allowed every 6'.

Standard Packaging - Bundles to be 1 1/4' and longer; Average length, bundled or nested, 3 3/4'. Shorter Packaging - Average length for 7' and shorter packages, nested or otherwise, 3 1/2'.

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; a small tight knot every 3'; pin worm holes; burls and a reasonable amount of slightly open checks. Brown streaks should not extend the entire length of a piece. Two flag worm holes to every 8' are permitted. Slight imperfections in face work (torn grain) admitted. An intermittent, brown machine burn across the face not exceeding 1/4" width admitted. Also, a slight quantity of bark on the back or sides admitted. Will admit pieces with 1/2 tongue. Spot filling is generally required for open characters.

Standard Packaging - Bundles to be 1 1/4' and longer; Average length, bundled or nested, 3 1/4'. Shorter Packaging - Average length for 7' and shorter packages, nested or otherwise, 3'.

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" in diameter, large grub worm holes; and splits extending through the piece. Open characters such as checks and knot holes are admitted, buit must be sound and readily fill. Not more than 20" scant stock in thickness allowed to every 5'. 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" wide, 1/64" deep and not more than two each 3'. 1/4 tongue allowed. Extremely dark pieces are not to be included.

Standard Packaging - Bundles to be 1 1/4' and longer; Average length, bundled or nested, 2 3/4'. Shorter Packaging - Average length for 7' and shorter packages, nested or otherwise, 2 1/2'.

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" deep not admitted. Knot holes and open characters which will readily fill are admitted. A limited number of pieces with no tongue which may be face nailed are admitted.

Standard Packaging - Bundles to be 1 1/4' and longer; Average length, bundled or nested, 2 1/4'. Shorter Packaging - Average length for 7' and shorter packages, nested or otherwise, 2'.

NOFMA 1 1/4' SHORTS OAK
Pieces 9" to 18" long are to be bundled together and designated as 1 1/4' Shorts. Pieces graded NO. 1 COMMON, SELECT and CLEAR to be bundled together and designated NO. 1 COMMON & BETTER with pieces grading NO. 2 COMMON bundled separately and designated as such. Although pieces 6" under and only 3" over the nominal length of the bundle may be included, the pieces must average 1 1/4', which is achieved through the natural preponderance of longer lengths.

 

Hard Maple, Beech, Birch, Pecan - Three (3) Grades:

NOFMA grades for:
 Select & Better Hard Maple (shown)
 Select & Better Beech
 Select & Better Birch

Has a face practically free of all defects, but the natural color of the wood shall not be considered a defect. The highest standard grade, combines appearance and durability.

Will admit the following: variations in the natural color of the wood (with use of some finishes, slight shadows and color variation may appear); an occasional small, firm pin knot, not over 1/8" in diameter, provided it does not occur on edges or ends of strips; occasional dark green or black spots or streaks not over 1/4" wide and 3" long (or its equivalent) which may contain a tight check not over 1/2" long, provided it is boxed within the piece; bird's eyes and small burls; slightly torn grain; or similar defect which can be readily removed by the ordinary method of sanding the floor after it is laid; a slightly shallow place not over 12" long on underside of the flooring if it does not extend to either end of the piece. Pieces with 1/2 tongue for no more than 25% of the length are allowed. The wood must be sound and free of shake. Bark streaks shall not be permitted.

Bundles shall be 1-1/4' and longer through 7' or 8' as the stock will produce. Not over 55% of the total footage shall be in bundles under 4'; Not more than 25% of the total footage shall be in 2' bundles, and not more than 10% of the footage shall be in 1-1/4' bundles. Nested bundles (standard packaging): maximum average number of pieces under 1-1/4' shall be 8 pieces. Average length is 3'.

NOFMA grades for:
#1 Common Hard Maple (shown)
#1 Common Beech
#1 Common Birch

A floor with varying wood characteristics and colors to include distinct color variations, numerous streaks, stained sapwood, sound knots, and checks. All defects must readily fill.

Will admit the following: sound tight knots, provided they do not occur on edges or ends of strips; slight imperfections in machining; distinct color variations; sticker stain/shadow; numerous dark green or black spots or streaks, provided they do not occur in combination with predominantly dark heartwood; slight checks not exceeding 3" in length (may be slightly open) and running parallel with and well inside the edges and ends of the strips; dark spots or streaks with slight checks in center; small rough spots (torn grain) which cannot be wholly removed by ordinary method of sanding the floor after it is laid; slightly torn edges; short tongue if sufficient to hold properly in the floor; shallow or waney back, if piece has sufficient bearing of full thickness to support it in the floor; small bark streaks where bark is as sound as surrounding wood; and slight variation in angle of end matching. The face shall be free of shake and wood must be sound.

Bundles shall be 1-1/4' and longer through 7' or 8', as the stock will produce. Not over 60% of the total footage shall be in bundles under 4', not more than 27% of the total footage shall be in 2' bundles; and not more than 15% of the footage shall be in 1-1/4' bundles. Nested bundles (standard packaging): maximum average number of pieces under 1-1/4' shall be 12 pieces. Average length 2 3/4'.

NOFMA grades for:
#2 Common Hard Maple (shown)
#2 Common Beech
#2 Common Birch

Must be of such character as will lay and give a good serviceable floor. The wood must be firm, serviceable and may contain all defects common to maple. Pieces with 1/4 full tongue admitted.

Third grade will not admit- knot holes over 3/8" in diameter or unsound knots where the unsound portion is over 1" in diameter; voids on ends or edges; or shake, heart checks, badly split ends and imperfections in manufacture which would materially impair the serviceability of the floor.

Bundles shall be 1-1/4' and longer through 7' or 8', as the stock will produce. Not over 85% of the total footage shall be in bundles under 4'; and not more than 55% of the total footage shall be 1-1/4' bundles. Nested bundles (standard packaging): maximum average number of pieces under 1-1/4' shall be 42. Average length 2 1/4'.

PREFINISHED OAK GRADING RULES

White Oak and Red Oak in STANDARD & BETTER Grades with a natural coloration, to be separated. All other colors and grades may be mixed Red Oak and White Oak. Grades are established after the flooring has been sanded and finished.

PRIME PREFINISHED OAK
This is the top grade and the overall appearance shall be good. The face of strips shall be selected for appearance after finishing. This grade includes characteristics found in the unfinished grades of CLEAR and SELECT grade.

The following characters are admitted: unlimited sapwood and the natural variations of color; occasional small burls; light brown steaks not more than 1/8" in width and 6" in length or the equivalent; an occasional very small tight 1/8" knot; and limited 1/32" fine pinworm holes, may be included in any one piece when properly filled. Will not admit pieces with less than 3/4 full tongue. Minimum average length 3 1/4'. Bundles 1 1/4' and up.

STANDARD PREFINISHED OAK
The face of strips may contain sound wood characteristics which are even and smooth after filling and finishing. This grade includes some characteristics found in the unfinished grades SELECT, NO.1 COMMON, and NO. 2 COMMON.

The following characters are admitted; worm holes; season and kiln checks, broken knots up to 3/8" in diameter, minor imperfections in machining, torn grain and burns. Other characters will be admitted if they do not impair the soundness of the floor. All larger admitted open characters are to be properly filled and finished. Limited unfinished/unfilled small open grade characters permitted.

Large grub worm holes, splits extending through the piece, shake and similar unsound defects not admitted.

For naturally finished coloration- all the varying color characteristics of the wood admitted to include, Sticker Stain, and Dark Streaks up to 3/8" in width not to exceed 1" in length for each lineal foot.

For stained finishes- all varying colorations and streaks permitted, predominantly dark boards not permitted. Minimum average length 2 1/2'. Bundles 1 1/4' and up.

STANDARD & BETTER PREFINISHED OAK
A combination of PRIME and STANDARD grade developing from the production run. Minimum average length 2 1/2'. Bundles 1 1/4' and up.

TAVERN PREFINISHED OAK
Should lay a serviceable floor.A limited amount of unfilled/unfinished open characters admitted. A limited amount of pieces with finish irregularities such as bubbles, small skips, lines, stain/color variation, surface handling scratches, minor trash, and the like are allowed.

The following characters are NOT admitted: mis-manufactured boards; shattered or rotten ends; large open knots and other unsound defects of a similar nature; pieces with less than 1/4 full tongue. Minimum average length 2'. Bundles 1 1/4' and up.

TAVERN & BETTER PREFINISHED OAK
A combination of PRIME, STANDARD and TAVERN grades developing from the production run. Minimum average length 2'.

 

 

NOFMA GRAIN DESCRIPTIONS ( Cuts) for OAK

PLAIN SAWN
QUARTER SAWN
RIFT SAWN
QUARTER/RIFT SAWN

PLAIN SAWN: flooring that is marked or specified as PLAIN SAWN or PLAIN, may contain any combination of the following types of grain classification. Also, flooring without a grain designation may contain any combination of the types of grain classification: Plain Sawn, Rift Sawn, and Quarter Sawn.

QUARTER SAWN: flooring that is marked or specified as QUARTER SAWN or QUARTERED; at least 50% of the piece must contain Quartered characteristics.

Quartered characteristics as defined by NOFMA are: In cross section the angle of the annual ring tangent to the face of the piece to be between 45° and 90°. Grain lines to be mostly parallel to the length of strips, and medullary ray flecks present and more than 1/16" wide.

RIFT SAWN: Flooring that is marked or specified as RIFT SAWN or RIFT; at least 75% of the piece must contain Rift characteristics.

Rift characteristics as defined by NOFMA are: In cross section the angle of the annual ring tangent to the face of the piece to be between 30° to 60°. Grain lines to be mostly parallel to the length of strips and medullary ray flecks less than 1/16" wide.

QUARTER/RIFT SAWN: Flooring that is marked or specified as NOFMA QUARTER/RIFT SAWN or QUARTER/RIFT, is a combination of QUARTER SAWN and RIFT SAWN developing from the production run.

CONSTRUCTION TECHNIQUES