#4 COMMON GRADE - BOARDS
Lumber of this grade is more widely used than other grades for general construction purposes. Boards of this grade are used for sub-floors, roof and wall-sheathing, concrete forms, low-cost fencing, crating and similar types of construction. Although appearance is given consideration, pieces are graded chiefly for serviceability as they are seldom used in exposed construction. Characteristics permitted and limiting provisions shall be:
Checks - seasoning, large. Roller checks medium to heavy, full length on back, light to medium 2/3 length on face.
Crook - as per NLGA ‘Crook Table for Commons’ (Para. 810b)
Cup - heavy
Pin Holes or Small Holes - not limited
Knots - limited as follows
| Face Width |
Fixed Knots
Firm & Tight
Knots
|
Loose Knots
Knot Holes
|
| 2" |
1" |
3/4" |
| 3" |
1 3/4" |
1" |
| 4" |
3" |
1 1/2" |
| 6" |
3 1/2" |
2" |
| 8" |
2/3 width |
2 1/2" |
| 10" |
2/3 width |
3" |
| 12" |
2/3 width |
3 1/2" |
| 14" & wider |
2/3 width |
4" |
*knot holes and/or loose knots of maximum size are limited to three for each 12’ of length. |
|
Pitch - heavy streaks and patches of massed pitch over 1/2 area in otherwise high quality pieces.
Pockets - large.
Shake - medium to heavy full length.
Skips - hit and miss on face, ” scant full length if surfaced one side. One edge may be ¼” scant for 1/2 length or ” scant full length.
Splits - 1/3 length.
Stain - heavy
Torn Grain - heavy
Twist - 7/4 and thinner, medium. 8/4 and thicker, 1/2 of medium.
Unsound Wood or Honey Comb - not firm, scattered spots over 1/4 the face.
Wane - 1/2 the thickness and 1/8 the width, 1/6 length on face; heavy on back, but equivalent to knot holes if through thickness.
White Speck & Honey Comb - firm. |
