Modulus of Rupture (Flexural Strength)
Ambient
125° F
-20° F

ASTM D6109

2,782 psi
1,902 psi
4,041 psi

Modulus of Elasticity (Flexural)
Ambient

Ambient

125° F
- 20° F

ASTM D6109

363,000 psi (Traditional board)
406,000 psi (Tongue & Groove board)
181,000 psi
620,000 psi

Compression (a)

ASTM D6108

3,495 psi (board)
5,340 psi (panel)
6,270 psi (rib)

Self Ignition Temperature

ASTM D1929

806° F

Flame Spread Index

ASTM E84

100

Smoke Developed Index

ASTM E84

165

Water Absorption

ASTM D1037

1.0% (24 hr immersion)
(24% for pressure treated lumber) [24 hr]

Moisture Expansion

24 hr – 0.01% (sidewise)
7 day – 0.095% (sidewise)
40 day - length - less than 0.05%
40 day - width 0.5%
40 day - depth 2.5%

Moisture Content (brushed surface)

ASTM D1037

0.6%

Thermal Expansion/Contraction

ASTM E228

3.58 X 10 -5/° F

Freeze-Thaw Resistance Flexure
Flexural Strength
Flexural Modulus

ASTM D6109

2,556 psi
287,000 psi

Flexure at 21-Day Water Soak
Flexural Strength
Flexural Modulus

ASTM D6109

2,744 psi
367,000 psi

Fungus Resistance
(soil block cultures)

ASTM D1413

White rot – zero effect
Brown rot – zero effect

Termite Resistance

ASTM D3345

No attack
(Block ratings 10)

Specific Gravity

ASTM D1037

1.20 g/cm3

Tensile Strength

ASTM D143

1,660 psi

Tensile Modulus

ASTM D143

403,000 psi (rib)
421,000 psi (panel)

Shear Strength

ASTM D905

1,223 psi

Static Coefficient of Friction Dry, Leather

ASTM D2047

0.51/.55

Static Coefficient of Friction Wet, Leather

ASTM D2047

0.85-0.90/did not slip

Nail Withdrawal
(8d, 2-1/2 Primeguard Stainless Spiral
Thread Deck Nail, driven through the
hollow portion of the board)

ASTM D1761

23.6 lbs.

Direct Nail Pull Through Test
(8d, 2-1/2 Primeguard Stainless Spiral
Thread Deck Nail, driven through the
hollow portion of the board)

ASTM D1037

255 lbs.

Lateral Resistance/Slip
(Main member: 2x6 Treated Southern Pine;
Side Member: GeoDeck Composite Deck Board)
(8d, 2-1/2 Primeguard Stainless Spiral Thread Deck
Nail, driven through the hollow portion of the board)
Ultimate Load
Load at 0.3”

ASTM D1761

291 lbs.
284 lbs.

Abrasion Resistance
(brushed surface)

ASTM D4060

3.02 g/1000 cycles

Hardness

ASTM D143

678 lbs. (flange)
298 lbs. (web)

Puncture Resistance

ASTM D3763 (modified)

592 lbs.

Stair Tread Flexure

ASTM D6109

Passes (300 lbs. at midspan ICC
requirement, with deflection no more than
L/180)

Creep Recovery

ICC Requirement

84% (at 156 lbs load, 16” span)
94% (at 246 lbs load, 20” span)

Weight (5/4 x 6 in)

1.80 lbs./ft.

Weathering

ASTM G155

Mahogany, Cedar and Driftwood - negligible
fading after 6,000 hrs at 102 min/18 min
cycle regime (UV and UV/water spray)

Effect of weathering on flexural strength
(on modulus of rupture)

ASTM G155
ASTM D6109

Negligible

Effect of maximum water absorption on flexural strength

ASTM D6109

Negligible (see above)

Effect of triple freeze-thaw cycles on flexural strength

ASTM D6109

Negligible (see above)