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3.2.1 Lumber Grading

a) Lumber Association rules shall not be used, since even their highest grades permit defects unacceptable in Product and are not based upon the use of the whole board but, rather on a percentage of the board. Lumber rules in this standard apply only to wood surfaces visible after manufacture and installation.

b) Lumber grade rules in this standard apply to boards exceeding 6.4 mm [.250”] in thickness.

3.2.2 Moisture Content of Lumber

a) Shall be in compliance with AWI 200 Care & Storage Standard.

3.2.3 Lumber for Exterior Use

a) Requires the lumber to be preservative treated in accordance with WDMA I.S. 4-15 (latest edition), unless the lumber is classified as 'Resistant or Very Resistant' in accordance with The Forest Products Laboratory Wood Handbook (latest edition).

3.2.4 Methods of Sawing

a) Plain-sawn lumber (See Figure 2).

b) Quarter-sawn lumber (See Figure 3).

c) Rift-sawn lumber (See Figure 4) is primarily reserved for oaks. Rift-sawn oak shall allow up to twenty-five percent of the exposed surface area to contain medullary ray (often referred to as fleck).

3.2.5 Filling of Natural Characteristics

a) Filling of checks, splits, and other open characteristics is permitted when inconspicuous after final finish and is the responsibility of the manufacturer/supplier.

3.2.6 Unlisted Species Rules

a) For species not listed, size/exposed area of permitted natural characteristics shall be as agreed to between owner/design professional and manufacturer/supplier.

3.2.7 Adhesive Requirements

3.2.7.1 Glues for Laminating Lumber

a) When gluing lumber for thickness and/or width or lay-up of veneered construction, the appropriate adhesive shall be used in accordance with manufacturer/supplier's documented instructions and be:

Adhesive Type Use Case
Type I For Non-Climate Controlled Interior or Exterior
Type II For Climate Controlled Use

3.2.7.2 Grain Orientation of Glue-Ups

a) End grain of glued components shall be alternated. (See Figure 66 and Figure 67)

3.2.8 Dimensional Requirements

 

3.2.8.2 Lumber Dimensions

a) Lumber dimensions are specified in the following order: by thickness, followed by width (across the grain), followed by length (along the grain). (See Figure 65)

Figure 65

Figure 65

3.2.8.2 Minimum Milled Thickness

a) Lumber and profiled components shall be:

Nominal Measurement Rough Thickness = Milled Thickness
4/4 25.4 mm [1"] = 19.1 mm [.750"]
5/4 31.8 mm [1.250"] = 25.4 mm [1"]
6/4 38.1 mm [1.500"] = 31.8 mm [1.250"]
8/4 50.8 mm [2"] = 44.4 mm [1.687"]
10/4 63.5 mm [2.500"] = 55.6 mm [2.189"]
12/4 76.2 mm [3"] = 68.2 mm [2.687"]
16/4 101.6 mm [4"] = 93.6 mm [3.687"]

b) When machine sanded, a reduction of .8 mm [.031"] off the thicknesses shown in this table is permitted.

3.2.9 Special Characteristics

a) Such as sapwood, heartwood, ribbon stripe, quarter-sawn, and vertical grain are not required unless specified.

3.2.10 Hardwood Requirements

a) Hardwood material requirements apply only to the following commonly-used species:

 Common Market Name  Scientific Name
 Alder  Alnus spp.
 Anigre  Pouteria spp.
 Ash  Fraxinus spp.
 Basswood  Tilia americana
 Beech  Fagus spp.
 Birch  Betula spp.
 Cherry, black  Prunus spp.
 Hickory  Carya spp. (excluding C. illinoinensis, C. aquatica, C. cordiformis, and C. myristiciformis)
 Lauan (Meranti)  Shorea spp.
 Mahogany, African  Khaya spp.
 Mahogany, American  Swietenia spp.
 Mahogany, Asian/Australian  Toona spp. (including T. calantas)
 Makore  Tieghemella spp.
 Maple, hard  Acer saccharum or A. nigrum
 Maple, soft  Acer spp. (excluding saccharum and nigrum)
 Oak, red  Quercus spp. (including rubra)
 Oak, white  Quercus spp. (including alba)
 Pecan  Carya illinoinensis, C. aquatica, C. cordiformis, and C. myristiciformis
 Poplar  Liriodendron tulipifera
 Sapele  Entandrophragma cylindricum
 Teak  Tectona grandis
 Walnut, black  Juglans spp.

3.2.10.1 Gluing for Thickness

a) Is permitted at the option of the manufacturer/supplier for hardwoods, when finished dimensions exceed 27 mm [1.063”]. (See Figure 67)

Figure 67

Figure 67

3.2.10.2 Gluing for Width

a) Is permitted at the option of the manufacturer/supplier for hardwoods, when finished dimensions exceed 139.7 mm [5.500”] or 108 mm [4.250”] in alder, black cherry, select white/red birch, maple, quarter-sawn or rift-sawn white/red oak, black walnut, or white ash.

3.2.10.3 Material Requirements for Opaque Finished Hardwood

a) Matching for color is not required when gluing for thickness or width.

3.2.10.4 Characteristics for Opaque Finished Hardwood

Allowances for the quantity, proximity, size, and distribution of natural characteristics in any one board’s exposed face for opaque finish:

Characteristic Premium Custom Economy
Characteristics permitted None in any face smaller than 258,064 mm sq. [400" sq.] None in any face smaller than 193,548 mm sq. [300" sq.] None in any face smaller than 192,032 mm sq. [200" sq.]
One permitted for each additional 129,032 mm sq. [200" sq.] One permitted for each additional 96,774 mm sq. [150" sq.] One permitted for each additional 65,516 mm sq. [100" sq.]
Max 3 per board Max 4 per board Max 5 per board
No knots, pitch pockets/streaks within 914 mm [36"] of one another No knots, pitch pockets/streaks within 610 mm [24"] of one another No knots, pitch pockets/streaks within 457 mm [18"] of one another
Bark pocket None None None
Bird’s eye, sound or filled Unlimited Unlimited Unlimited
Burl, sound <19.1 mm [.750"] dia. <25.4 mm [1"] dia. <25.4 mm [1"] dia.
Check, filled <1 mm W x 101.6 mm L [.039" x 4"] <2 mm W x 152.4 mm L [.078" x 6"] <2 mm W x 299 mmL [.078" x 9"]
Honeycomb None None None
Knot, sound & tight <9.5 mm [.375"] dia. <15.9 mm [.625"] dia. <25.4 mm [1"] dia.
Knot, checked & filled <6.4 mm [.250"] dia. <12.7 mm [.500"] dia. <19.1 mm [.750”] dia.
Knot hole, filled <3.2 mm [.125"] dia. <6.4 mm [.250"] dia. <12.7 mm [.500"] dia.
Mineral stain/ streak Unlimited Unlimited Unlimited
Patch ≤ 38.1 mm [1.500"] W x 88.9 mm L [3.500"] ≤ 38.1 mm [1.500"] W x 88.9 mm L [3.500"] ≤ 38.1 mm [1.500"] W x 88.9 mm L [3.500"]
Pitch pocket/pitch streak, filled <2 mm [.078"] W x 76.2 mm [3"] L or 3.2 mm [.125"] x 50.8 mm [2"] <2 mm [.078"] W x 152.4 mm [6"] L or 3.2 mm [.125"] W x 101.6 mm [4"] L <2 mm [.078"] W x 152.4 mm [6"] L or 3.2 mm [.125"] W x 101.6 mm [4"] L
Sapwood Unlimited Unlimited Unlimited
Shake, filled ≤1.6 mm [.063"] W x 50.8 mm [2"] ≤3.2 mm [.125"] W x 76.2 mm [3"] L ≤6.4 mm [.250"] W x 76.2 mm [3"] L
Split, filled ≤.8 mm [.031"] W x 101.6 mm [4"] L ≤1.6 mm [.063"] W x 152.4 mm [6"] L ≤2.4 mm [.094"] W x 203 mm [8"] L
Sticker shadow Unlimited Unlimited Unlimited
Wormholes, filled None ≤1.6 mm [.063"] in diameter 3.2 mm [.125"] in diameter

 

3.2.10.5 Material Requirements for Transparent Finished Hardwood

a) Matching, when glued for thickness/width or when veneered construction, shall be:

Premium Custom Economy
Well-matched for color and grain Compatible for color and grain Not required

3.2.10.6 Characteristics for Transparent Finished Hardwood 

a) Allowances for the quantity, proximity, size, and distribution of natural characteristics in any one board’s exposed face for transparent finish for all hardwoods:

Characteristic Premium Custom Economy
Characteristics permitted 2 ea. without knots, pitch pockets/streaks within 1219 mm [48"] of one another. 3 ea. without knots, pitch pockets/streaks within 914 mm [36"] of one another. 4 ea. without knots, pitch pockets/streaks within 610 mm [24"] of one another.
Bark pocket None None None
Bird’s eye, sound Unlimited Unlimited Unlimited
Bird’s eye, checked None ≤ 10% of face Unlimited
Burl, sound ≤ 12.7 mm [.500"] dia. ≤ 25.4 mm [1"] dia. Unlimited
Check ≤ .8 mm [.031"] W x 101.6 mm [4"] L ≤ 1.6 mm [.063"] W x 152.4 mm [6"] L ≤ 2.4 mm [.094"] W x 203 mm [8"] L
Heartwood in select white ash, birch, and maple None None None
Honeycomb None None None
Knot, sound and light ≤ 3.2 mm [.125"] dia. ≤ 6.4 mm [.250"] dia. ≤ 9.5 mm [.375"] dia.
Knot, checked None ≤ 6.4 mm [.250"] dia. ≤ 12.7 mm [.500"] dia.
Knot hole None None None
Mineral Stain None 10% of face Unlimited
Patch None ≤ 38.1 mm [1.500"] w x 88.9 mm [3.500"] L ≤ 38.1 mm [1.500"] w x 88.9 mm [3.500"] L
    Inconspicuous from 914 mm [36"] Inconspicuous from 1524 mm [60"]
Pitch pocket/ streak None None ≤ 1.6 mm [.063"] W x 152.4 mm [6"] L or 3.2 mm [.125"] W x 101.6 mm [4"] L
Sapwood in unselected species Unlimited Unlimited Unlimited
Sapwood in red birch and brown ash None None None
Sapwood in black cherry and black walnut ≤ 5% of face ≤ 10% of face Unlimited
Shake None None ≤ 3.2 mm [.126"] W x 76.2 mm [3"] L
Split ≤ .8 mm [.031"] W x 101.6 mm [4"] L ≤ 1.6 mm [.063"] W x 152.4 mm [6"] L ≤ 2.4 mm [.094"] W x 203 mm [8"] L
Sticker shadow None None ≤ 10% of face
Wormhole, filled None ≤ 1.6 mm [.063”] dia. ≤ 3.2 mm [.125”] dia.

 

3.2.10.8 Hardwood Species-Specific Requirements 

a) Tolerances for the quantity, proximity, and distribution of natural characteristics in any one board’s exposed face for transparent finish for:

b) Alder, natural ash, natural birch, lauan, American mahogany, African mahogany, natural hard maple, natural soft maple, poplar, red oak, white oak, and teak:

Premium Custom Economy
None in any face smaller than 387,096 mm sq. [600" sq.] None in any face smaller than 258,064 mm sq. [400" sq.] None in any face smaller than 193,548 mm sq. [300" sq.]
One permitted for each additional 129,032 mm sq. [200" sq.] One permitted for each additional 96,744 mm sq. [150" sq.] One permitted for each additional 64,516 mm sq. [100" sq.]

c) For select brown ash, select red and white birch, and select white maple

Premium Custom Economy
None in any face smaller than 322,580 mm sq. [500" sq.] None in any face smaller than 225,806 mm sq. [350" sq.] None in any face smaller than 129,032 mm sq. [200" sq.]
One permitted for each additional 12,039 mm sq. [200" sq.] One permitted for each additional 96,774 mm sq. [150" sq.] One permitted for each additional 64,516 mm sq. [100" sq.]

d) For black cherry, white oak, red oak, and black walnut:

Premium Custom Economy
None in any face smaller than 193,548 mm sq. [300" sq.] None in any face smaller than 129,032 mm sq. [200" sq.] None in any face smaller than 96,744 mm sq. [150" sq.]
One permitted for each additional 96,774 mm sq. [150" sq.]. One permitted for each additional 64,516 mm sq. [100" sq.] One permitted for each additional 48,387 mm sq. [75" sq.]

3.2.11 Softwood Materials

a) Softwood materials apply to western red cedar, ponderosa pine, sugar pine, eastern white pine, eastern white cedar, hemlock, Douglas fir, and redwood. For species not listed, length requirements and size/exposed area of permitted natural characteristics shall be as agreed to between owner/design professional and manufacturer/supplier.

b) Apply only to the following commonly-used species:

Common Market Name Scientific Name
Douglas-Fir Pseudotsuga menziesii
Redwood Sequoia sempervirens
Cedar, red Thuja plicata, Juniperus virginiana, Toona ciliata
Cedar, white Chamaecyparis thyoides, Cupressus lusitanica, Thuja occidentalis
Cedar, other Cryptomeria japonica, Melia azedarach
Pine Pinus spp.

3.2.11.1 Gluing for Thickness 

a) Is permitted at the option of the manufacturer/supplier for softwoods, when finished dimensions exceed 38.1 mm [1.500”]. (See Figure 67)

Figure 67

Figure 67

3.2.11.2 Gluing for Width

a) Is permitted when finished dimensions exceed 178 mm [7”]. (See Figure 66)

Figure 66

Figure 66

3.2.11.3 Gluing for Width and/or Thickness in Transparent Finished Softwood 

Premium Custom Economy
Components shall be well matched for color and grain. Components shall be compatible for color and grain. No matching for color or grain required.

3.2.11.4 Vertical Grain 

a) Shall have a minimum average of 5 growth rings per 25.4 mm [1”].

3.2.11.5 Characteristics for Opaque Finished Softwood 

a) Natural characteristics are permitted only if they are inconspicuous after final finish.

b) Tolerances for the quantity, proximity, and distribution of natural characteristics in any one board’s exposed face when inconspicuous after final finish:

Characteristic Premium Custom Economy
Characteristics permitted None in any face smaller than 387,096 mm sq. [600" sq.] None in any face smaller than 258,064 mm sq. [400" sq.] None in any face smaller than 129,032 mm sq. [200" sq.]
  One permitted for each additional 129,032 mm sq. [200" sq.] One permitted for each additional 96,774 mm sq. [150" sq.] One permitted for each additional 64,516 mm sq. [100" sq.]
  Max 3 per board Max 4 per board Max 5 per board
  No knots, pitch pockets/streaks within 914 mm [36”] of one another No knots, pitch pockets/streaks within 610 mm [24”] of one another No knots, pitch pockets/streaks within 457 mm [18”] of one another
Bark pocket None None None
Bird’s eye, sound or filled Unlimited Unlimited Unlimited
Burl, sound <19.1 mm [.750"] dia. <25.4 mm [1"] dia. <25.4 mm [1"] dia.
Check, filled <.8 mm [.031"] W x 101.6 mm [4"] L <1.6 mm [.063"] W x 152.4 mm [6"] L <2.4 mm [.094"] w x 229 mm [9"] L
Honeycomb None None None
Knot, sound & tight < 9.5 mm [.375"] dia. < 15.9 mm [.625"] dia. < 25.4 mm [1"] dia.
Knot hole, filled < 3.2 mm [.125"] dia. < 6.4 mm [.250"] dia. < 12.7 mm [.500"] dia.
Mineral Stain/ Mineral Streak Unlimited Unlimited Unlimited
Patch ≤ 38.1 mm [1.500"] w x 88.9 mm [3.500"] L ≤ 38.1 mm [1.500"] w x 88.9 mm [3.500"] L ≤ 38.1 mm [1.500"] w x 88.9 mm [3.500"] L
Pitch Pocket/Pitch Streak < 1.6 mm [.063"] W x 76.2 mm [3"] L or 3.2 mm [.125"] x 50.8 mm [2"] < 1.6 mm [.063"] W x 152.4 mm [6"] L or 3.2 mm [.125"] x 101.6 mm [4"] < 1.6 mm [.063"] W x 152.4 mm [6"] L or 3.2 mm [.125"] x 101.6 mm [4"]
Sapwood Unlimited Unlimited Unlimited
Shake, filled ≤ 1.6 mm [.063"] W x 50.8 mm [2"] L ≤ 3.2 mm [.125"] W x 76.2 mm [3"] L ≤ 6.4 mm [.250"] W x 76.2 mm [3"] L
Split, filled ≤ .8 mm [.031"] W x 101.6 mm [4"] L ≤ 1.6 mm [.063"] W x 152.4 mm [6"] L ≤ 2.4 mm [.094"] W x 203 mm [8"] L
Sticker Shadow Unlimited Unlimited Unlimited
Wormhole, filled None 1.6 mm [.063"] dia. 3.2 mm [.125"]

 

3.2.11.6 Characteristics for Transparent Finished Softwood 

Tolerances for the quantity, proximity, and distribution of natural characteristics in any one board’s exposed face when inconspicuous after final finish:

Characteristic Premium Custom Economy
Characteristics permitted None in any face smaller than 580,644 mm sq. [900" sq.] None in any face smaller than 387,096 mm sq. [600" sq.] None in any face smaller than 258,064 mm sq. [400" sq.]
  One permitted for each additional 258,064 mm sq. [400" sq.] One permitted for each additional 193,548 mm sq. [300" sq.] One permitted for each additional 129,032 mm sq. [200" sq.]
  Max 2 per board Max 3 per board Max 4 per board
  No knots, pitch pockets/streaks within 1219 mm [48"] of one another No knots, pitch pockets/streaks within 914 mm [36"] of one another No knots, pitch pockets/streaks within 610 mm [24"] of one another
Bark pocket None None None
Bird’s eye, sound or filled Unlimited Unlimited Unlimited
Bird’s eye, checked None ≤ 10% of face Unlimited
Burl, sound ≤ 12.7 mm [.500"] dia. ≤ 15.9 mm [.625"] dia. ≤ 19.1 mm [.750"] dia.
Check < .8 mm [.031"] W x 101.6 mm [4"] L < 1.6 mm [.063"] W x 152.4 mm [6"] L < 2.4 mm [.094"] W x 203 mm [8"] L
Honeycomb None None None
Knot, sound and tight < 6.4 mm [.250"] dia. < 12.7 mm [.500"] dia. < 19.1 mm [.750"] dia.
Knot hole None None None
Mineral stain/ mineral streak None ≤ 10% of face Unlimited
Patch < None ≤ 38.1 mm [1.500"] w x 88.9 mm [3.500"] L ≤ 38.1 mm [1.500"] w x 88.9 mm [3.500"] L
None Inconspicuous at 914 mm [36”] Inconspicuous at 1524 mm [60”]
Pitch pocket/pitch streak None <1.6 mm [.063”] W x 76.2 mm [3”] L or 3.2 mm [.125”] x 50.8 mm [2”] <1.6 mm [.063”] W x 152.4 mm [6”] L or 3.2 mm [.125”] x 101.6 mm [4”]
Sapwood in unselected species Unlimited Unlimited Unlimited
Sapwood in all heart redwood None None None
Shake None ≤ 1.6 mm [.063"] W x 50.8 mm [2"] L ≤ 3.2 mm [.125"] W x 76.2 mm [3"] L
Split None ≤ .8 mm [.031"] W x 101.6 mm [4"] L ≤ 1.6 mm [.063"] W x 152.4 mm [6"]
Sticker shadow None None 10% of face
Wormhole, filled None ≤1.6 mm [.063"] dia. ≤ 3.2 mm [.126"] dia. 

3.2.12 Reclaimed/Reconstituted Timber and Lumber Products 

a) Reclaimed/reconstituted timber and lumber products shall be provided and used as agreed upon between buyer and seller.

3.2.13 Cathedral-Type Figure 

a) Cathedral type figure shall be achieved by a single component in ANSI HPVA HP-1 (latest edition) “AA” face grade or the split heart method in face grades “A-D.” Each half of a split heart shall be subject to the minimum component width requirements for face grade “B”.