Standard Sizing

Dimension Lumber dressed, S4S1

ThicknessWidth
NominalDressedNominalDressed
DryGreenDryGreen
inchesinchesmminchesmminchesinchesmminchesmm
2
2-1/2
3
3-1/2
4		1-1/2
2
2-1/2
3
3-1/2		38
51
64
76
89
2-1/16
2-9/16
3-1/16
3-9/16
52
65
78
90		2
3
4
5
6
8
10
12
14
16
18
20		1-1/2
2-1/2
3-1/2
4-1/2
5-1/2
7-1/4
9-1/4
11-1/4
13-1/4
15-1/4
17-1/4
19-1/4		38
64
89
114
140
184
235
286
337
387
438
489
2-9/16
3-9/16
4-5/8
5-5/8
7-1/2
9-1/2
11-1/2
13-1/2
15-1/2
17-1/2
19-1/2
65
90
117
143
190
241
292
343
394
444
495
Timbers dressed, S4S1Timbers dressed, S4S1Timbers dressed, S4S1Timbers dressed, S4S1Timbers dressed, S4S1Timbers dressed, S4S1
5" & thicker1/2' off nominal1/2' off nominal5" & thicker1/2' off nominal1/2' off nominal

Boards dressed, S4S, dry

NominalDressedNominalDressed
inchesinchesmminchesinchesmm
1
1-1/4
1-1/2		3/4
1
1-1/4		19
25
32		2
3
4
5
6
7
8
9
10
11
12
over 12		1-1/2
2-1/2
3-1/2
4-1/2
5-1/2
6-1/2
7-1/4
8-1/4
9-1/4
10-1/4
11-1/4
3/4" off
nominal		38
64
89
114
140
165
184
210
235
260
286
19 mm off
nominal

Finish dressed, dry

NominalDressedNominalDressed
inchesinchesmminchesinchesmm
3/8
1/2
5/8
3/4
1
1-1/4
1-1/2
1-3/4
2
2-1/2
3
3-1/2
4		5/16
7/16
9/16
5/8
3/4
1
1-1/4
1-3/8
1-1/2
2
2-1/2
3
3-1/2		8
11
14
16
19
25
32
35
38
51
64
76
89		2
3
4
5
6
7
8
9
10
11
12
14
16		1-1/2
2-1/2
3-1/2
4-1/2
5-1/2
6-1/2
7-1/4
8-1/4
9-1/4
10-1/4
11-1/4
13-1/4
15-1/4		38
64
89
114
140
165
184
210
235
260
286
337
387

Radius Edge Decking dressed, S4S, dry

NominalDressedNominalDressed
inchesinchesmminchesinchesmm
1-1/141254
5
6		3-1/2
4-1/2
5-1/2		89
114
140

(1) Dimension Lumber 2″ thick and less than 14″ wide is required to be dry with a moisture content of 19% or less. Heavy Dimension Lumber (2×14 and wider, 2-1/2″ thick by all widths, and 3×3 and larger) and Timbers are not required to be dry unless specified. Thicknesses apply to their corresponding widths as squares and wider, except a thickness of 1-9/16″ applies to nominal 2″ in widths of 14″ and wider if dressed green. (In 2″ Dimension, widths over 12″ are not customary stock sizes, so 2×14 and wider sizes are usually produced only on special order.)

(2) Boards less than the minimum dressed thickness for 1″ nominal but which are 5/8″ or greater thickness dry may be regarded as American Standard Lumber, but such Boards shall be marked to show the size and condition of seasoning at the time of dressing. They shall also be distinguished from 1″ Boards on invoices and certificates.