Thuja plicata, commonly called western red cedar or Pacific red cedar, giant arborvitae or western arborvitae, giant cedar, or shinglewood, is a species of Thuja, an evergreen coniferous tree in the cypress family native to western North America. It is not a true cedar of the genus Cedrus.
Western Red Cedar trees produce their own thujaplicin, a chemical substance that is known to have anti-fungal and anti-bacterial properties. It’s also said to be an anti-oxidant. Long before it was used in modern construction, Western Red Cedar played a large role in the lives of Native Americans. So much that they called it “the Tree of Life”.
Native to the Pacific Northwest, where Cedar Country Lumber is located, we are proud suppliers of Western Red Cedar building materials for new construction, as well as historical restorations. Over the years, we have had the pleasure of working with the North Cascades National Park staff on many of their projects, including some at Stehekin.
Accessible only by foot, boat, or plane, Stehekin is located on the Northern shores of Lake Chelan in Eastern Washington and offers many outdoor activities, including hiking, biking, fishing, camping, and kayaking. For visitors wishing to spend the night with amenities, there are cabins, a house, and rooms for rent, as well as a restaurant and general store.
Special “thanks” to our friends, the Roberts, for capturing these photos on their recent trip to Stehekin!
Knotty Western Red Cedar Siding
Hand Split Western Red Cedar Shakes
Western Red Cedar Board and Batten Siding
Select Tight Knot Western Red Cedar
Before your next project, be sure to visit us! We ship nationwide!
When it comes to choosing building materials for a remodel or your new custom home, it is hard to beat the natural beauty, versatility, and reliability of Western Red Cedar.
Available in many different grades, Western Red Cedar can be used to customize your home’s exterior with a wide variety of siding patterns, shingles and shakes, as well trim and soffit materials. Because it is pitch and resin-free, it is able to accept a wide range of finishes, from semi-transparent stains that allow the natural wood beauty to shine through to darker stains that show the character (or add a “beachy feel”), as well as traditional solid colors. No matter your unique style, you can be sure when you choose Western Red Cedar, you will be able to create the custom look for your home that is just right for you.
Please enjoy these photos of two custom homes in Anacortes, WA, that we supplied all the exterior Western Red Cedar for. Each house was designed and built by different custom home builders; however, both homeowners choose similar cedar products, including custom stained Western Red Cedar shingles as exterior cladding with painted Cedar trim. By choosing totally different stains for the cedar shingles, along with the other unique details of each home, including the Western Red Cedar fences, you can see how versatile and beautiful Western Red Cedar truly is.
One of the lightest commercial softwoods, the density of Western Red Cedar at oven-dry conditions is approximately 21 pounds per cubic foot with a relative density (specific gravity) of 0.32. Comparative oven-dry densities of cedar and some other softwood species are given in the Table 1 below.
Cedar’s low density enhances its insulation value and makes it an easy wood to transport and handle.
We ship nationwide! This container was loaded for transport to Hawaii
DIMENSIONAL STABILITY
Like all woods, Western Red Cedar is hygroscopic and will absorb or discharge moisture to attain equilibrium with the surrounding atmosphere. The size differential between dry and unseasoned Western Red Cedar is given in Table 2 below.
Shrinkage in both the radial and tangential directions is given in Table 3 below.
Cedar has a very low shrinkage factor and is superior to all other coniferous woods in its resistance to warping, twisting, and checking.
THERMAL CONDUCTIVITY
Wood is an excellent thermal insulator. This is an important characteristic since good thermal insulators help keep buildings cool in the summer and reduce heating costs in the winter. The conduction of heat in wood is directly related to its density. Woods with low density have the highest thermal insulating value because such woods contain a high proportion of cell cavities. In dry wood, these cavities are filled with air, one of the best-known thermal insulators.
With its low density and high proportion of air spaces, Western Red Cedar is the best thermal insulator among the commonly available softwood species and is far superior to brick, concrete, or steel.
Hurricane Sandy unfortunately destroyed this amazing project we supplied the cedar for on Fire Island.
It has a coefficient of thermal conductivity (k value) at 12% mc of 0.74 BTU inch/ft 2h degrees F. The R-value (the reciprocal of k) for Western Red Cedar is 1.35″ (34mm) of thickness.
ACCOUSTICAL PROPERTIES
An important acoustical property of wood is its ability to damp vibrations. Wood has a cellular network of minute interlocking pores that convert sound energy into heat by frictional and viscoelastic resistance. Because of the high internal friction created by the cellular pore network, wood has more sound damping capacity than most structural materials. Floor, ceiling, and wall assemblies of wood can provide effective, economical sound insulation and absorption when properly utilized.
Western Red Cedar is particularly effective in sound damping and can help reduce noise or confine it to certain areas.
photo and craftsmanship by Ravenhill of Friday Harbor, WA
FLAME SPREADING
Flame spreading ratings describe the surface burning characteristics of interior finishes. They are used to regulate the use of interior finish materials to reduce the probability of rapid fire spread. Materials are burned in a test furnace for a relative assessment of flammability. The lower the flame spread rating, the more the material resists the spread of fire.
Building codes in North America generally define as interior finish any exposed material that forms part of the building interior. This usually includes interior wall and ceiling finishes, flooring, windows, doors, and other wood products. US codes set the maximum flame spread rating for interior wall, and ceiling finishes in most buildings at 200.
The flame spread rating for Western Red Cedar is 69 (Class II rating), which is much lower than the average finishes.
Smoke-developed classifications reflect the amount of smoke released by burning material. They are used in conjunction with the flame spread ratings to regulate the use of interior finish materials where the potential to generate smoke or control smoke movement is of major fire safety importance.
The smoke-developed classification for Western Red Cedar is 98. US codes set the maximum smoke developed classification for interior wall, and ceiling finishes in most buildings at 450.
Western Red Cedar’s flame spread rating and smoke developed classification compare well with the ratings of many other softwood and hardwood species.
Western Red Cedar can be used for an interior finish in some building applications where other species would not be permitted because of its favorable performance.
photo and craftsmanship by Impel Construction of Stanwood, WA
DURABILITY
Historically, native peoples of the Pacific coast prized cedar for its long-lasting qualities and used wood and bark from cedar trees for most of their building needs.
Evidence of cedar’s durability are the many cedar artifacts still in good condition today.
we supplied the full, rough sawn Western Red Cedar for this project on Long Island, NY
Properly finished and maintained, cedar will deliver decades of trouble-free service. If exposed for prolonged periods to conditions where decay could be a factor, such as where the wood is in contact with the ground, cedar should be treated with suitable wood preservatives.
FASTENING
Western Red Cedar has good fastening properties, but its natural preservatives have a corrosive effect on some unprotected metals in close contact, causing a black stain on the wood. Fasteners should be corrosive resistant such as aluminum, brass, silicon bronze, hot-dipped galvanized, or stainless steel. Read more about choosing the right fasteners for your job HERE.
Nails and screws used to fasten Western Red Cedar should be about one-third longer than those used to fasten hardwood species. It also works well with a wide range of adhesives.
Because it is free of pitch and resin, Western Red Cedar has excellent gluing properties.
FINISHING
Although cedar is a naturally durable species, leaving it untreated is not recommended because a finish or protective coating will greatly increase its service life.
Cedar is free of pitch, and with its high degree of dimensional stability, it is the best of the softwoods for accepting paints, stains, oils, and other coatings.
we supplied the Western Red Cedar for this stunning project for Smith Gardens in Marysville, WA
WORKABILITY
Cedar takes a fine finish in all hand and machine operations, takes fasteners without splitting, and is easily sawn and nailed. When working with Western Red Cedar, sharp cutters are recommended.
With its straight grain and uniform texture, Western Red Cedar is among the easiest and most rewarding woods to work with.
PRODUCTS, GRADES, AND SIZES
There are few more versatile building materials than Western Red Cedar, which is ideal both for indoor and outdoor uses. Western Red Cedar lumber is available in visual stress grades for construction and finishing uses in a range of lengths, widths, and thicknesses. It is available in clear or knotty grades with smooth-surfaced, combed, or rough sawn finishes; kiln dried or unseasoned (green); flat grain and vertical grain.
Western Red Cedar is used to manufacture a range of specialty products such
as siding, paneling, roofing, structural decking, and outdoor decking.
Table 1. Comparative Softwood Densities (PCF)
SPECIES OVEN-DRY DENSITY
Western Red Cedar 21
Douglas Fir 31
Ponderosa Pine 27
Southern Pine 34
Table 2. Size Differential Between Unseasoned and Dry Lumber
SIZE DIFFERENTIAL NOMINAL BETWEEN UNSEASONED DIMENSION AND DRY LUMBER (INCHES) AFTER SURFACING (INCHES)
1½ or less 1/32
2 to 4 1/16
5 to 7 1/8
8 or more 1/4
Table 3. Shrinkage of Western Red Cedar
FROM KILN DRIED
FROM GREEN (25% OR (15% AVERAGE
GREATER MOISTURE MOISTURE
DIRECTION CONTENT) TO: CONTENT) TO:
