Cedar

Cedar is a wonderfully versatile wood used in many different exterior applications. Most cedar is sourced in Canada, with smaller amounts in Washington and Oregon states. Current production in British Columbia, Canada is using only 1/3 of 1% in annual harvest. Western Red Cedar (WRC) (Thuja plicata) is one of North America’s great renewable resources. Slow growing and naturally durable. Western Red Cedar has one of the longest life spans of any North American softwood. It produces long lengths of timber with true, straight grain. It is free from pitch and its heartwood has natural decay resistance. Its low density gives it an insulation value superior to most other species. Cedar is lightweight, easy to work, easy to finish, possessing outstanding dimensional stability. Western Red Cedar is a preferred wood for nearly all purposes where attractive appearance or resistance to weather is important. The cedar lumber mill association has a great website that covers product, installation, finishing, grades and more: www.wrcla.org.

Grades

Cedar is one of the most confusing woods to purchase since beyond clear and vertical grain, most other grades are proprietary. This translates to the mills or distributors assigning whatever name they choose. Cedar, like all wood boards, is graded to one side and two edges only. In the specific case of cedar, it is graded to the rough side only (i.e. S1S2E ). However, a few general terms are universal:

Clear: No knots, cedar is graded to the rough sawn side (as applicable). All grading applies to just one side and one or two edges.

Select Knotty or STK (Select Tight Knot): Not in any grade book. It refers to boards that are chosen for their general good appearance with solid, tight knots that should not fall out.

Rough Sawn: Milling process leaving the wood rough–typically the treatment most people identify with cedar.

Smooth Sawn: Milling boards to a smooth appearance.

S1S2E: One side and two edges are smooth, leaving the opposing side “rough”.

No Hole: generally refers to pickets where the picket—when graded—had no open knotholes, although with no gauranty the knots could fall out in the future, leaving a hole.

Green: Wood of any specie that has not been dried during the milling process.

Dried: Wood of any specie that has been allowed to give up the moisture in the cell structure. The processes include kiln dried, heat treated, air dried and partially air dried.

Species

Western Red Cedar: The most common and readily available.

Alaskan Yellow Cedar: Actually a type of Cypress.

Inland Red Cedar: A form of Western Red Cedar growing in different locations. Log quality and size are limited for consistency.

Decking

All wood used in the outdoors must be protected against decay and insect attack. Not only is Western Red Cedar one of the few woods with its own preservative oils, its freedom from pitch and resin makes it an excellent base for protective coatings. It is stable, light weight, easily worked and ideal for most finishes. Like all woods, Western Red Cedar is hygroscopic and will absorb or discharge moisture to attain equilibrium with the surrounding atmosphere. However, it has a very low shrinkage factor and is superior to all other coniferous woods in its resistance to warping, twisting and checking. Left without a finish, it can grey out to a long lasting, maintenance free deck. Western Red Cedar has twice the extractives as fir species, creating its aroma, tannins, insect and rot resistance.

Fencing

Cedar wood products are a natural and very common choice for fencing due to its long life, natural appearance, cost–effectiveness and availability. Most cedar fence components are relatively similar with the exception of pickets. Please consider the relative costs of options as a guide to their equating quality. Less expensive pickets will be thinner (down to 3/8” thick), allow for open knotholes &/or loose knots. Conversely, better quality pickets will have fewer knots that must be tight in the wood, up to 7/8” thick and will be some variation of a dried product. As with all wood products, pickets are graded on just one side.

Siding

Cedar siding is available in stock in a multitude of patterns and sizes. In addition, many other patterns are available on short lead times. On existing construction, siding can be the hardest item to match to pattern and size. It is strongly recommended that you bring a sample (even if very weathered or damaged) to obtain the best possible match. Matching older siding is ALWAYS a challenge due to the wide range of ages, sizes and varieties manufactured.

“Lap” sidings are in strips or individual board sizes ranging in width from 4” to 16”. This type includes boards in a variety of sizes and patterns. 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 winter.

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 which is 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 and steel.

Installation Reminders

Poor installation creates special issues and will severely hamper performance. A few general reminders:

Space deck boards to allow for water and debris drainage, including end joints.

Generally do not exceed spans of greater than 16” on decking or siding applications.

Hand nailing is recommended on siding, preferably in a “splitless” variety with a ring or screw shank.

ALL fasteners will eventually stain the wood except for aluminum or stainless steel varieties. 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.

Pre-finishing is always the best way to ensure good coverage. We recommend that all wood sidings be pre-stained to not only save time in sealing the products after installation, but to ensure getting a good seal coat on all the surfaces of the boards. Please see us for more information on this available service.

Most cedar products should be allowed to acclimate on the job prior to installation.

In hot and dry conditions, like we see in Colorado, T&G or shiplap patterns are the better alternatives. Additional nailing may need to be completed to prevent cupping.

Joints

Joint treatment is very important in siding as not only a connection method between panels or laps, but it should also provide a weather-tight seal to protect your house against the elements. The different types of joints are:

Lap sidings are simply nailed so that a piece overlaps over the top of the piece below it. Therefore all rain, etc is shed downward and away from the wall.

Tongue and groove (T&G) patterns are machined in such a fashion that the edge of one board is narrower to fit into a groove/slot of the next. This type of pattern should ALWAYS be used horizontally for exterior applications, with the first board groove side down. Many T&G patterns are milled with a different pattern on opposite sides. Alternatively, they may be rough sawn on one exposure and smooth sawn on the opposite.

Shiplap sidings are an adapted T&G, except that the machined edge of one piece fits over the machined edge of the next.
Butt joints are generally not an acceptable type of joint except on end to end applications where the joint is vertical. Butt joints are the method where the siding stops at trim or corners.

Sizing

Cedar as a rule is “oversized” compared to standard lumber. Expect 1x boards in a 7/8” thickness, 2x and greater sizes to be nearer to full measurement. For example, a 2x8 will be closer to a true 2”x8”. 1x boards are generally only available in 2’ increments up to 16’. 2x and greater dimensions are available in up to 20’ lengths.

Sizes stocked by Front Range Lumber include:

  Lengths:
6' 8' 10' 12' 14' 16' 20'
5/4x6 decking X X X X X X  
2x2 rough sawn   X X        
1x2 S1S2E     X        
1x4 S1S2E X* X X X X X  
1x6 S1S2E X* X X X X X  
1x8 S1S2E   X X X X X  
1x10 S1S2E   X X X X X  
1x12 S1S2E   X X X X X  
2x4 rough sawn   X* X* X X X X
2x6 rough sawn   X X X X X X
2x8 rough sawn   X X X X X X
2x10 rough sawn   X X X X X X
2x12 rough sawn   X X X X X X
4x4 rough sawn   X* X* X      
4x6 rough sawn   X X X      
6x6 rough sawn X* X X X   X  
1x6 T&G S1S2E   X X X X X  
1x8 “channel rustic”   X X X X    

* Fence grade, pickets are “dog-eared."