Side-by-Side Comparison
Lumber & Wood
Dimensional Lumber vs. Janka Wood Hardness Scale
Comparing 2 standards across 17 specifications. 17 key differences identified.
Comparing:
Dimensional Lumber
Janka Wood Hardness Scale
Dimensional lumber sizes under the American Softwood Lumber Standard (DOC PS 20) define the difference between rough-sawn 'nominal' green lumber designations and finished 'actual' Surfaced 4-Sides (S4S) dry dimensions. A standard 2×4 measures exactly 1.5 × 3.5 inches (38 × 89 mm) following planing and kiln drying.
The Janka Wood Hardness Scale is standardized under ASTM D143 (and ISO 3350) by measuring the exact force (in pounds-force / lbf or Newtons) required to embed an 11.28 mm (0.444 in) steel ball to half its diameter into a wood sample, establishing the international benchmark for hardwood flooring and lumber dent resistance.
Specification Comparison Table
17 Parameters| Parameter / Spec | ||
|---|---|---|
|
Governing Standard
|
DOC PS 20-20 / NIST / American Lumber Standard Committee (ALSC) | — |
|
Surfacing Condition
|
S4S (Surfaced 4 Sides) Kiln-Dried (KD19, moisture content ≤19%) | — |
|
2×4 Actual Dimensions
|
1.5 × 3.5 inches (38 × 89 mm) | — |
|
2×6 Actual Dimensions
|
1.5 × 5.5 inches (38 × 140 mm) | — |
|
2×8 Actual Dimensions
|
1.5 × 7.25 inches (38 × 184 mm) | — |
|
2×10 Actual Dimensions
|
1.5 × 9.25 inches (38 × 235 mm) | — |
|
2×12 Actual Dimensions
|
1.5 × 11.25 inches (38 × 286 mm) | — |
|
4×4 Actual Dimensions
|
3.5 × 3.5 inches (89 × 89 mm) | — |
|
6×6 Actual Dimensions
|
5.5 × 5.5 inches (140 × 140 mm) | — |
|
Governing Standards
|
— | ASTM D143 Section 13 (Hardness Test) / ISO 3350 / USDA Forest Products Laboratory (FPL) |
|
Test Metric Definition
|
— | Force in pounds-force (lbf) to embed an 11.28 mm (0.444 in / 100 mm² area) steel ball into wood at 12% moisture content |
|
Red Oak Industry Benchmark
|
— | 1,290 lbf (5,740 N) | The universal 100% benchmark standard against which all flooring is compared |
|
Softwoods (Pine / Fir / Cedar)
|
— | Eastern White Pine: 380 lbf | Douglas Fir: 660 lbf | Southern Yellow Pine: 690 lbf |
|
Medium Domestic Hardwoods
|
— | Black Walnut: 1,010 lbf | Black Cherry: 950 lbf | Teak: 1,155 lbf |
|
Hard Domestic Standards
|
— | White Oak: 1,360 lbf | Hard / Sugar Maple: 1,450 lbf | White Ash: 1,320 lbf |
|
Ultra-Hard Woods (Hickory / Exotic)
|
— | Shagbark Hickory: 1,820 lbf | Santos Mahogany: 2,200 lbf | Brazilian Cherry (Jatoba): 2,350 lbf | Ipe: 3,680 lbf |
|
Softest vs Hardest Known Woods
|
— | Balsa: 100 lbf (0.44 kN) vs Australian Buloke: 5,060 lbf (22.5 kN) |