One benefit of installing Western red cedar siding is the beauty of its natural finish. But some homeowners may desire—or feel the need—for painting cedar siding. And by paint, we mean an opaque exterior finish—not a solid color stain.
We consulted Paul Mackie of the Western Red Cedar Lumber Association (WRCLA) to help us answer common questions. (Please note that abbreviated terms “cedar” and “red cedar” refer to the same product: Western red cedar.)
Why Paint Rather Than Apply Other Surface Treatments?
The type of finish selected is driven by style preference, and truly what one wants the siding to look like and frequency of re-finishing.
Western red cedar siding that's finished on all six sides with a stain-blocking primer and top coated with 100% acrylic latex paint has the longest expected service life for the coating system. Factory-applied finishes of this type are available in most market areas.
Is There a "Painted Cedar" Style or Is It Just About Practicality?
Yes, there is a style. It is not all about protection. In many markets, like New England for example, painted siding is the preferred "look."
Beyond that, Western red cedar has multiple advantages over other cladding options because it’s natural, sustainable and a renewal product. It’s easy to install and is available in almost unlimited sizes and patterns for those that want a unique "look."
Can You Paint Cedar Without Priming It First?
Yes, but it is strongly discouraged. A two-coat system, primer with a paint top coat, will have a significantly longer service life than will a single coat of paint (or solid stain). Paint without a primer applied to weathered wood will have adhesion difficulties.
What Painting Techniques Work Better For Cedar? Such as Spraying vs. Hand Brushing vs. Rolling?
Hand-brushing is recommended. For refinishing, hand-brushing is always preferred. If one chooses to spray apply, the best results will be achieved by back brushing the finish during application. It is likely that hand-brushing will get more paint on the wood.
Is There an Optimal Window of Time For Painting Cedar?
Paint within 2 weeks. Wait no more than 12 weeks. Many don’t know that Western red cedar has a natural resistance to rot, decay, and insect attack. For best results, if the paint is the selected top coat, fresh siding should be pre-primed on all six sides with a stain blocking primer and top coated with 100% acrylic latex paint. Alkyd-oil primers are recommended, but one may choose a high-quality latex primer as long as it contains stain blockers.
Allowing fresh siding to “weather” for as little as two weeks negatively affects coating adhesion. Test results from the Forest Products Testing Lab (run by the USDA for the Forest Service), show that after 12 weeks of exposure to sunlight, cedar siding has lost 50% of its ability to hold a film-forming coating system like primer and paint.
There is a sample of Western red cedar siding on the test fence at the testing lab in Madison, Wisconsin. It was pre-primed on all six sides (including the ends), top coated with two coats of paint and placed in a frame.
It has never been re-coated, shows no degradation of the coating system, and has been on the test fence for more than 24 years. Other samples were allowed to weather for 3 months, 6 months, 9 months, and 12 months before being primed and painted.
The longer the siding was allowed to weather, the sooner the coating system failed. And in all of those cases, it failed to start at the end grain where the siding abutted trim because the ends of the siding had not been primed.
Can Extremely Old Cedar Be Painted?
Yes, but it requires heavy preparation. Even then, the paint is not expected to last long. Surface preparation is key to success when dealing with weathered wood.
The siding must be free from mold, mildew, and dirt. Loosened (photodegraded) surface fibers, and any loosened remaining finish must be removed prior to re-finishing. Sanding is an option on smooth face siding and commercial strippers/restorers are available to accomplish this task.
Does Vertical Grain Cedar Hold Paint Better Than Flat Grain?
Yes. Because of cell structure orientation, vertical grain cedar absorbs alkyd-oil stain blocking primers better than flat grain cedar.
However, knotty cedar holds these primers well because most knotty cedar siding patterns have a textured or re-sawn face.
Can You Use Self-Priming Paint With Cedar?
The Western Red Cedar Lumber Association (WRCLA) has not seen any test data on the supposed self-priming paints. Factory finish warranties provided by primer and paint manufacturers apply to cedar siding that has one coat of primer and one or two top coats of paint.