Priming New Cedar Siding

Priming western red cedar helps the wood s natural properties stay put.

Priming new cedar siding.

Without a primer tannins from within the cedar mix with moisture and seep to the wood s surface naturally staining and discoloring the surface. These paints form a tough but flexible film that allows moisture within the wood to escape while protecting the cedar from atmospheric moisture that might lead to extractive bleed. Be sure that your primer is appropriate for the surface you re painting. Do not use water borne primers over exposed cedar siding.

Water borne primers cannot block the tannins in the cedar. Allow it to dry for the amount of time specified on the instruction label. As a general rule use an alkyd primer and a latex topcoat when repainting. What that means is that you can put primer on the cedar siding but brown stains will come through.

Apply one even thorough coat of water repellant preservative to the cedar siding with a paint brush or roller. This stain covers all wood grain completely and gives the wood an appearance of being painted. Hardboard siding may also require a primer. According to paul mackie at the western red cedar lumber association wrcla red cedar siding that has been finished on all six sides with a stain blocking primer and top coated with 100 percent exterior acrylic latex paint has the longest expected service life of any coating system.

Staining cedar siding differs from application of paint and other finishes. If possible stain all sides of the siding before installation. This is called extractive bleeding a naturally occurring process that does not affect western red cedar s properties. Cedar and redwood for example usually require an oil based primer to seal the surface so that tannin stains don t bleed through the topcoat.

First remove any mill glaze a hard shiny surface on one side of the siding by sanding. Stains dry rapidly and fresh stain applied over dried stain will show lap marks.