Solid Color Stain

These opaque stains fully cover, coat, and protect the wood from UV and moisture. Solid stains, like paints, sit on the surface and form a film, but they are still quite good for most exterior siding and trim applications. For decking, however, solid body finishes are not recommended because they will flake or peel.

Solid stains may be applied to Western Red Cedar by brush, roller, or pad. Brush application is usually the best. These stains perform similarly to and are applied like paint. One coat of solid-color stain is only marginally adequate on new wood. A prime coat with a topcoat will always provide better protection to the wood as well as promoting a longer service. Optimal performance can be obtained if the wood is primed, and then given two coats of stain. Topcoats of acrylic latex solid-color stains are generally superior to all others, especially when two coats are applied over a primer. Unlike paint, a solid-color stain may leave lap marks. To prevent lap marks, follow the procedures suggested for semi-transparent penetrating stains.

Properly applied in the field, one coat of solid color stain can be expected to last up to 5 or 6 years. Factory applied finishes are available that come with warranties on the finish of 15-25 years depending on the number of topcoats.

Photos: Birdseye; courtesy of Western Red Cedar Lumber Association

Semi-transparent graphite stain provides a dark black look contrasted with some areas of wood-colored stained cedar. Project: Terrapin. Location: Woodstock, Vermont. Architect: Brian J. Mac, FAIA, Jeff Kamuda, AIA. Project Manager: Birdseye

Paint

Painting provides the most surface protection against weathering and wetting by water, while providing color and concealment of some of the wood’s characteristics. Although paint can reduce wood’s absorption of water, paint itself is not a preservative. Paints of all types such as water-based paints, acrylic (latex), acrylic enamel, and solvent-based paints (alkyd and oil-modified) are suitable for Western Red Cedar. Test results show that good quality latex paint maintains its mechanical adhesion through dimensional changes of the wood during wet and dry moisture cycles. For this reason, finishes with high elasticity generally maintain adhesion better than brittle finishes during extended periods of exposure to outdoor weathering.

Based on all of the above, there are clearly many different options and choices for finishing exterior Western Red Cedar. Yet, there are some design trends worth noting. Currently, the two most popular finishes for siding and trim include:

• Driftwood gray bleaching stain. This may need to be reapplied every four to five years in order to provide a uniform grey look all at once and be consistent. Reapplication is primarily for water repellency.
• Noir/ black/ charcoal solid stain or semi-transparent stain. This dark coloration is often used in combination with natural-looking cedar that is protected but visible for a dramatic and appealing result.

Of course, many other appearance finishes continue to be used as well.

Photo: Brit Kwasney; courtesy of Western Red Cedar Lumber Association

The heart of this higher education building is the clear finished cedar-paneled central lobby, a celebration space which mimics a hollow cedar tree which is common to this region. Project: Wii Gyemsiga Siwilaawksat Student Housing at Coast Mountain College. Location: Terrace, British Columbia, Canada. Architect: hcma

FINISHING CEDAR FOR INTERIOR APPLICATIONS

The interior finishing of WRC should be looked at completely differently due to the lack of exposure to UV and moisture. Of course, exterior finishes (transparent, semi-transparent, and opaque) can be used where appropriate indoors such as in bathrooms, kitchens, or other high humidity areas or in areas where visual contrast is being sought. Otherwise, there are several other popular choices where a higher level of protection is not required.

Most design professionals selecting Western Red Cedar for use indoors seek to retain its natural appearance. This is best achieved using transparent finishes such as waxes, shellac and other clear film forming finishes. These “interior” finishes provide some protection to the cedar from minor abrasion and liquids (less so with wax) and make cleaning easier.

Before applying an interior finish, Western Red Cedar may require cleaning or light sanding with fine-grit sandpaper to remove any minor surface characteristics. It is good practice to experiment with the proposed finish on a small sample of wood identical to the product to be finished. This will ensure that the coating will achieve the desired look. Once the decision has been made about the type of finish, the same brand name product should be used throughout to avoid incompatible formulations and color variations

Interior Finish Choices

There are several interior finishing options that are quite appropriate and common for Western Red Cedar.

• Unfinished: If left in its natural state, some darkening of the wood can be expected as it ages, and any color variations will become less pronounced.
• Transparent Finishes: Clear finishes or water-based acrylic, polyurethane, acrylic/polyurethanes, and clear plastics (non-yellowing) are excellent options for finishing Western Red Cedar. These finishes can be brushed on to produce a coating that does not mask the natural appearance of cedar. They contain very low levels of solvents and other compounds that can reduce indoor air quality. They are available in flat (matte), satin (semigloss), and gloss finishes from a number of manufacturers. When choosing a brand, it is important to specify a nonyellowing formula unless an amber tint to the Western Red Cedar is preferred. High-gloss polyurethanes provide the most durable finish, but the highly reflective surface may be objectionable to some. These products are not suitable for exterior use.
• Bleached Finishes: These result in a sun-bleached driftwood look. It can be achieved with commercially available bleaching agents. After bleaching, the Western Red Cedar can be left in its natural state or given a coat of clear sealer.
• Clear Wax: This finish option is for smooth surfaced cedar. Few finishes bring out its inner luster so well. There are also unpigmented liquid waxes on the market that incorporate a penetrating vehicle.
• Oils: Danish oil, tung oil, and boiled linseed oil are widely available and easily applied to smooth or textured Western Red Cedar; however, they tend to darken the wood and should be tested on a sample before final application.
• Lacquer: Clear lacquer can be used for smooth surfaces. It is an unobtrusive finish that helps to retain much of Western Red Cedar’s natural beauty. It is not recommended, however, for kitchens and bathrooms or areas that require more than light dusting for regular household cleaning. Due to their fast-drying characteristics, some lacquers are best applied with an air-less sprayer rather than with a brush. For the best results, two or more coats are recommended and sanded with the grain between applications. For optimum surface durability, the first coat may be of high gloss lacquer followed by one or two coats of matte or satin lacquer.
• Varnish: Clear varnish is recommended only for smooth surfaces. It will inevitably add a richer, darker tone to cedar. Two coats applied by brush are acceptable for most areas, but additional coats should be added for kitchen and bathroom use. The surface will be slightly brittle and may show scratches, but these can be touched up with a tinted wax. Varnish-finished surfaces can be cleaned with soapy water or wiped with thinners. Varnish stains are varnishes to which color pigment has been added. Although difficult to apply, they are available in a broad choice of tones and tints.

As noted, other finishes are possible too, including those used for exteriors. They are just less common for interior use, particularly if they cover or mask the natural beauty and grain of the wood.

CONCLUSION

Western Red Cedar continues to be a popular and durable choice for buildings all around North America. Proper finishing of the cedar enhances its beauty and helps ensure that its appearance and durability of the wood are preserved, particularly in exterior applications. Understanding the different options covered in this course helps to achieve these results. It also helps architects convey to building owners realistic expectations for maintenance and refinishing requirements as the building is used and enjoyed.

Peter J. Arsenault, FAIA, NCARB, LEED AP is a nationally known architect and a prolific author advancing more sustainable buildings through the power of design. www.pjaarch.com, www.linkedin.com/in/pjaarch