Hardwood Floor Grading


Hardwood Flooring Pre-Delivery Checklist for Builders

National Oak Flooring Manufactures Association Oak Flooring Grading Guide


RULE— The face shall be practically clear, admitting an average of 3/8-inch of bright sap. The question of natural color shall not be considered. Bundles to be 1-1/4 foot and longer. Average length 3-3/4 feet.
GUIDE— Will admit the following minor defects: 3/8-inch bright sap entire length of strip or equivalent if not extending further than one inch for 1/3 length of piece. Small burls and fine pin worm holes, or in the absence of these, one thin brown streak 3 inches long to be allowed to every 6 feet. Will admit pieces with 3/4 full tongue. This is the top grade and must provide a finished floor of excellent appearance.


RULE— The face may contain sap, small streaks, pin worm holes, burls, slight imperfections in working, and small tight knots which do not average more than one to every 3 feet. Bundles to be 1-1/4 foot and longer. Average length 3-1/4 feet.

GUIDE— May contain unlimited sound sap, slight imperfections in milling, small tight knot every 3 feet, pin worm holes, burls and reasonable amount of season and kiln checks. Streaks not running the entire length of piece, 2 flag worm holes to every 8 feet permitted. Slight imperfections in face work (torn grain) admitted. Also a slight quantity of bark on the back or sides admitted. Will admit pieces with 1/2 full tongue. Most of these defects are lost sight of after the floor is laid and finished giving a good appearance. Bundles to be 1-1/4 foot and longer.

No. 1 Common

RULES— Shall lay a good residential floor and may contain varying wood characteristics, such as flags, heavy streaks and checks, worms holes, knots and minor imperfections in working. Bundles to be 1-1/4 foot and longer. Average length 2-3/4 feet.

GUIDE— Shall lay a good sound floor. No broken knots over 1/2-inch in diameter, large grub worm holes, splits extending through the piece, or other unsound defects admitted. Defects admitted must readily fill. Not more than 20 inches scant stock in thickness allowed to every 5 feet. Minor imperfections in machining permitted. Will admit pieces with 1/4 full tongue. It is recommended that extremely dark pieces not be included. Bundles to be 1-1/4 foot and longer.

No. 2 Common

RULES— May contain sound natural variations of the forest product and manufacturing imperfections. The purpose of this grade is to furnish an economical floor suitable for homes, general utility use, or where character marks and contrasting appearance is desired. Bundles to be 1-1/4 foot and longer.

GUIDE— Will admit defects of every character, but should lay a serviceable floor. The following defects are to be trimmed off: shattered or rotten ends, large broken knots, excessive bad millwork, shake, advanced rot, etc. Knot holes and defects which will readily fill are permitted. A limited number of pieces with no tongue admitted, which may be face nailed. Bundles to be 1-1/4 foot and longer.

3/4 x 2-1/4 Inch Nested Flooring

RULE— Rules applicable to grading and lengths of conventionally bundled flooring to apply.


Nested flooring is random length flooring bundled in runs, end to end continuously, in 8 foot long bundle.
A bundle with 4 layers of flooring 3 runs wide, or 6 layers by 2 runs wide, containing a good spread of lengths 9-inches — 102-inches nested continuously end to end to make bundles of 8 foot nominal length
(7-1/2 — 8-1/2 foot actual length) containing 24 board feet of flooring.

Checklist For Builders

Sanctioned by Western Washington Floor Covering Industry Trust

Check the job site before delivery. Be sure the flooring will not be exposed to high humidity or moisture. Surface drainage should direct water away from building. Basements and crawl spaces must be dry and well-ventilated. In joist construction with no basement, provision for outside cross ventilation must be provided through vents or other openings in the foundation walls. Total area of these openings should equal 1-1/2% of the first floor area. A ground cover of 4 or 6 mill polyethylene film is essential as a moisture barrier.

Protect flooring from excessive heat. Flooring installed over a heating plant or uninsulated heating ducts may develop cracks unless protection from the heat is provided. Use a double layer of 30 lbs. asphalt-saturated building paper or 30 lbs. asbestos felt, or 1/2″ standard insulation board between joists under the flooring in these areas. When job conditions are satisfactory, have the flooring delivered and broken up into small lots and stored in the rooms where it will be installed. Allow two to three days for the flooring to become acclimated to the job site

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