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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.
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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.
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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.
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.
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.
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DENSITY
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Bald
Cypress
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Atlantic White Cedar
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Aromatic Cedar
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Western
Red Cedar
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Old Growth Redwood
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Second Growth Redwood
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GREEN
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29.4
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21.7
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24.5
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21.7
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26.6
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23.8
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12% MC
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32.2
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22.4
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25.9
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22.4
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28.0
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24.5
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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.
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Shrinkage from Green to Oven Dry Moisture Content (%) |
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DIMENSIONAL STABILITY
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Bald
Cypress
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Atlantic White Cedar
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Aromatic Cedar
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Western Red Cedar
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Old Growth Redwood
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Second Growth Redwood
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Yellow Pine
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RADIAL
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3.8
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2.9
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3.3
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2.4
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2.6
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2.2
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4.6
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TANGENTIAL
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6.2
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5.4
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5.2
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5.0
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4.4
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4.9
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7.7
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Direction of Shrinkage
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Longitudinal
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Length |
Along the Grain (Negligible)
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Radial
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Thickness |
Across the Growth Rings
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Tangential
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Width |
In Direction of Growth Rings (Twice
as much as Radial)
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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.
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SIDE HARDNESS (# Force)
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Bald
Cypress |
Atlantic White Cedar
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Aromatic Cedar |
Western
Red Cedar |
Old Growth Redwood |
Second Growth Redwood
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GREEN |
390 |
290 |
390 |
260 |
410 |
350 |
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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.
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IMPACT BENDING (Drop in Inches)
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Bald
Cypress |
Atlantic White Cedar
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Aromatic Cedar |
Western
Red Cedar |
Old Growth Redwood |
Second Growth Redwood
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12% MC |
24 |
13 |
17 |
17 |
19 |
15 |
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*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.
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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.
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WORK to MAXIMUM LOAD (in lbf/in3)
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Bald
Cypress |
Atlantic White Cedar
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Aromatic Cedar |
Western
Red Cedar |
Old Growth Redwood |
Second Growth Redwood
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GREEN |
6.6 |
5.9 |
6.4 |
5.0 |
7.4 |
5.7 |
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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.
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MODULUS of ELASTICITY (PSI X
1 Million) |
Bald
Cypress |
Atlantic White Cedar
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Aromatic Cedar |
Western
Red Cedar |
Old Growth Redwood |
Second Growth Redwood
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GREEN |
1.18 |
0.75 |
0.84 |
0.94 |
1.18 |
0.96 |
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12% MC |
1.44 |
0.93 |
1.04 |
1.11 |
1.34 |
1.10 |
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*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. |
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.
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MODULUS of
RUPTURE (PSI) |
Bald
Cypress |
Atlantic White Cedar
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Aromatic Cedar |
Western
Red Cedar |
Old Growth Redwood |
Second Growth Redwood
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GREEN |
6,600 |
4,700 |
6,200 |
5,200 |
7,500 |
5,900 |
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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.
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SHEER STRESS PARALLEL TO GRAIN
(PSI) |
Bald
Cypress |
Atlantic White Cedar
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Aromatic Cedar |
Western
Red Cedar |
Old Growth Redwood |
Second Growth Redwood
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GREEN |
810 |
690 |
830 |
770 |
800 |
890 |
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12% MC |
1000 |
800 |
880 |
990 |
940 |
1110 |
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** 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.
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SPECIFIC GRAVITY |
Bald
Cypress |
Atlantic White Cedar
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Aromatic Cedar |
Western
Red Cedar |
Old Growth Redwood |
Second Growth Redwood
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GREEN |
.42 |
.31 |
.35 |
.31 |
.38 |
.34 |
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12% MC |
.46 |
.32 |
.36 |
.32 |
.40 |
.35 |
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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.
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TENSION PARALLEL TO GRAIN (PSI)
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Bald
Cypress |
Atlantic White Cedar
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Aromatic Cedar |
Western
Red Cedar |
Old Growth Redwood |
Second Growth Redwood
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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.
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TENSION PERPENDICULAR TO
GRAIN (PSI) |
Bald
Cypress |
Atlantic White Cedar
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Aromatic Cedar |
Western
Red Cedar |
Old Growth Redwood |
Second Growth Redwood
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12% MC |
270 |
220 |
270 |
220 |
240 |
250 |
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