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Cypress Lumber Grades & Mechanical Properties


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Cypress #2&Btr Common Grade


The common grades are useful for all types of general construction, finish, trim, pattern stock, and other uses where ordinary tree characteristics either enhance the appearance of the piece or do not restrict the appropriate application of the piece.


Natural character variations are considered attributes of the historic and economical #2&Btr common grade. Features include approximately 35% non-structural type character, including mainly sound knots, worm holes and mineral discolorations.

#2&Better Cypress Grade

Cypress Select Grade


The Select & Better grade is of the highest quality and should be specified for any use where specific lengths are required or when a consistent appearance is of the utmost importance.

NOTE: Although Select & Better is a premium finish grade it should not be considered a "Clear" grade.


Graded from better face with reverse side not below #1 Common. Sapwood is not considered a defect. Mainly tight, sound small knots and other minor character defects as permitted in National Hardwood Lumbermen's Assoc. (NHLA) grade rules.

Select Grade Cypress

This comparative information is the accumulated research derived from Forest Industry Books, the World Wide Web, Forest Products Research Laboratories, U.S. Dept of Agriculture information, and manuals by the Forest Products Research Society.  This data is believed to be accurate but not warranted, intended for informational purposes only.


Cypress Specie Information

Where does our cypress come from?

Our cypress comes from the coastal areas of Louisiana, Alabama, Georgia, Mississippi, Virginia, and North and South Carolina. While our inventory comes from the finest mills cypress mills, every piece is re-certified for grade prior to shipment, thereby meeting our strict quality standards.

Is our cypress Tidewater Red or all Heartwood?

Most of the cypress commercially available today is harvested from second or third growth forests. Most remaining virgin timber is protected in wildlife areas or National Parks. While our cypress does contain heartwood, we make no distinction. We do not sell cypress by color, grain or separated for sap or heartwood.

Finishing Recommendations for Cypress

Preparation: Before finishing, repair all nail holes and surface irregularities. All surfaces should be clean and caulking should be in good condition. Seasoned cypress siding should be finished promptly at the time of installation to protect against moisture absorption, discoloration from rain, and mildew. However under no circumstance should siding be finished when it is wet.

Selecting the right Primer and Paint

Use a high-quality primer compatible with the paint being used - most paints will require an oil-based alkyd primer. A high quality/100% resin acrylic/latex paint is recommended. Certain paints contain water-sensitive polymers and/or surfactants that might absorb moisture, causing the siding to swell or creating an environment suitable for biological degradation. These additives are present in a variety of paints, at difference price levels, and their presence is not necessarily reflected on the label. The only safe approach is to use a paint specifically recommended by a paint manufacturer for use on exterior wood siding. Light-colored finishes reflect heat more than dark colors and reduce the possibility of shrinking, checking, warping and loosening of nails.

Applying Paint

Always follow the primer and paint manufacturer's recommendations. Priming all sides and edges of wood siding provides superior performance over all types of sheathing. After the prime coat has dried, apply two coats of high-quality paint to all exposed surfaces and edges. Brush application is recommended because it provides a more uniform coverage. Time of day, temperature, dew, fog and rain influence the quality of the paint job. Follow paint manufacturers' recommendations in regard to these factors.

Applying Stains

Cypress accepts a stain very well. However, semi-transparent stains do not last long as paint systems. Most semi-transparent stains will provide adequate protection for only 18 to 24 months depending on local  weather conditions. Consequently, they require reapplication at regular intervals to protect the wood siding from warping, checking, shrinking, and loosening of nails.

Where it is desired to leave wood in its natural state, it should be brushed on all sides and edges with a quality clear, oil based wood preservative (preferably with an anti-fungal additive, such as WOODguard). Allow the water repellent to be absorbed and dry to the touch so the solvent will not react with foam sheathing. Clear coating must be re-applied at frequent intervals to maintain protection.

Mechanical Properties of Cypress

Cypress Density

Density is the weight of wood per cubic foot at a specified MC. Density is important to indicate strength in wood and may predict certain characteristics such as hardness, ease of machining and nailing resistance. A larger number indicates a stronger wood.

DENSITY

Bald

Cypress

Atlantic White Cedar

Aromatic Cedar

Western

Red Cedar

Old Growth Redwood

Second Growth Redwood

GREEN

29.4

21.7

24.5

21.7

26.6

23.8

12% MC

32.2

22.4

25.9

22.4

28.0

24.5

Dimensional Stability

Above the fiber saturation point* (roughly 30% MC), wood will not shrink or swell from changes in moisture content. However, wood changes in dimension as moisture content varies below the fiber saturation point. Wood shrinks as it loses moisture below the fiber saturation point and swells as it gains moisture up to the fiber saturation point. These dimensional changes may result in splitting, checking, and warping. The combined effects of shrinkage in the tangential and radial axes can distort the shape of wood pieces because of the difference in shrinkage and the curvature of the annual rings.

Shrinkage from Green to Oven Dry Moisture Content (%)

DIMENSIONAL STABILITY

Bald

Cypress

Atlantic White Cedar

Aromatic Cedar

Western
Red Cedar

Old Growth Redwood

Second Growth Redwood

Yellow Pine

RADIAL

3.8

2.9

3.3

2.4

2.6

2.2

4.6

TANGENTIAL

6.2

5.4

5.2

5.0

4.4

4.9

7.7

Dimensional Stability from Green to Kiln Dried

Direction of Shrinkage

Longitudinal

Length

Along the Grain (Negligible)

Radial

Thickness

Across the Growth Rings

Tangential

Width

In Direction of Growth Rings (Twice as much as Radial)

Hardness Rating

This test is defined as resistance to being compressed, nicked or dented.  It would also indicate the ease of nailing. In this test a .444 inch ball is embedded .222 inches.  The load required to do this is indicated in pounds of force.  The numbers are an average of radial and tangential* penetrations.

SIDE HARDNESS (# Force)

Bald

Cypress

Atlantic White Cedar

Aromatic Cedar

Western

Red Cedar

Old Growth Redwood

Second Growth Redwood

GREEN

390

290

390

260

410

350

12% MC

510

350

470

350

480

420

Impact Bending

This comparison shows the ability of wood to absorb shocks beyond the proportional limit*. In this test a 50lb hammer is dropped upon a beam. The height in inches shows how far the hammer fell to cause beam failure.

 

IMPACT BENDING (Drop in Inches)

Bald

Cypress

Atlantic White Cedar

Aromatic Cedar

Western

Red Cedar

Old Growth Redwood

Second Growth Redwood

12% MC

24

13

17

17

19

15

*PROPORTIONAL LIMIT is a term to describe a point where the strength of the wood and the load are even.  When stressed beyond this point, structural damage will occur.

Work to Maximum Load (Static Bending)

This test shows the ability to absorb shock with some permanent deformation and injury.  The WORK TO MAXIMUM LOAD (WML) evaluates the combined strength and toughness of wood under bending stress.

 

WORK to MAXIMUM LOAD (in lbf/in3)

Bald

Cypress

Atlantic White Cedar

Aromatic Cedar

Western

Red Cedar

Old Growth Redwood

Second Growth Redwood

GREEN

6.6

5.9

6.4

5.0

7.4

5.7

12% MC

8.2

4.1

5.4

5.8

6.9

5.2

Modulus of Elasticity

This is the measurement of stiffness that determines the deflection from a load.  An example would be boards on a floor.  They will recover to their original shape from a stress up to the proportional limit*, but when stressed beyond this point, a permanent set will remain.

The Modulus of Elasticity is not a force number, but a ratio of the stress applied up to the  proportional limit divided by the strain (the deflection over a given area).   In simple terms; take the force of 7200 PSI and divide it by the amount of deflection over a given area (.0050 in.) and you have a MOE of 1.44. The higher number on the chart indicates greater stiffness.

MODULUS of ELASTICITY
(PSI X

1 Million)

Bald

Cypress

Atlantic White Cedar

Aromatic Cedar

Western

Red Cedar

Old Growth Redwood

Second Growth Redwood

GREEN

1.18

0.75

0.84

0.94

1.18

0.96

12% MC

1.44

0.93

1.04

1.11

1.34

1.10

*PROPORTIONAL LIMIT is a term to describe a point where the strength of the wood and the load are even.  When stressed beyond this point, structural damage will occur.


Stiffness ratio of a species determines the deflection from a load

Modulus of Rupture

This measurement shows the maximum bending load that a board can support.  The number indicates the stress required to cause failure.  The higher number means that a greater force is required to cause failure.

MODULUS of

RUPTURE (PSI)

Bald

Cypress

Atlantic White Cedar

Aromatic Cedar

Western

Red Cedar

Old Growth Redwood

Second Growth Redwood

GREEN

6,600

4,700

6,200

5,200

7,500

5,900

12% MC

10,600

6.800

8,000

7,500

10,000

7,900

Shear Stress Parallel to Grain

Shear stress happens when a board surface is stressed from opposite directions.   It forces portions to move in a parallel, but, opposite direction. The number on this chart indicate the force in pounds per square inch (PSI) required to cause the wood to shear.  Values presented are average strength in radial and tangential shear planes.

SHEER STRESS PARALLEL TO GRAIN (PSI)

Bald

Cypress

Atlantic White Cedar

Aromatic Cedar

Western

Red Cedar

Old Growth Redwood

Second Growth Redwood

GREEN

810

690

830

770

800

890

12% MC

1000

800

880

990

940

1110

** Wood is very resistant to shearing perpendicular to grain and is not measured via a standard test.

Specific Gravity

Specific Gravity provides the relative weight of wood compared to an equal volume of water.  For many engineering applications, the basis for specific gravity is generally the oven dry weight and volume at a 12% moisture content (MC).  Specific gravity is used as a standard basis to compare species. A larger number indicates a heavier material.


SPECIFIC GRAVITY

Bald

Cypress

Atlantic White Cedar

Aromatic Cedar

Western

Red Cedar

Old Growth Redwood

Second Growth Redwood

GREEN

.42

.31

.35

.31

.38

.34

12% MC

.46

.32

.36

.32

.40

.35

OVEN DRY

.48

.35

.37

.34

.42

.36

Tensile Strength

Wood is strongest in Tension (pulling from each end) Parallel to Grain. The problem is how to harness all this strength.  Attachments at the ends to pull the wood to maximum would cause failure at both ends.

TENSION PARALLEL TO GRAIN (PSI)

Bald

Cypress

Atlantic White Cedar

Aromatic Cedar

Western

Red Cedar

Old Growth Redwood

Second Growth Redwood

12% MC

8,500

N/A

N/A

6,600

9,400

9,100

The second chart shows that wood has considerably less strength with Tension perpendicular to grain.

TENSION PERPENDICULAR  TO GRAIN (PSI)

Bald

Cypress

Atlantic White Cedar

Aromatic Cedar

Western

Red Cedar

Old Growth Redwood

Second Growth Redwood

12% MC

270

220

270

220

240

250

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