When to Seal
For best results, it's crucial for the surface of your cedar deck to be completely dry before applying the seal. Allow at least three days of dry weather before sealing.
There are several types of film-forming and penetrating finishes for a cedar wood deck. A penetrating finish provides better results since it allows the cedar to breath; it won't flake, crack or peel; and maintenance is relatively easy. Among the penetrating types are transparent finishes, such as water-repellent preservatives, and transparent stains which are popular for preserving the natural appearance of the cedar. A semi-transparent stain is another penetrating option which provides a bit of color. The pigment aids in the durability of the seal by blocking sunlight.
The deck should be cleaned with a deck cleaning product to remove any dirt and minor stains. Never use a power washer to do the cleaning, since it can damage the wood fibers and prevent the finish product from bonding properly. Depending on the texture of the cedar boards, a light sanding may be required. Use a fine-grit sandpaper to gently remove any minor flaws and smooth out the surface in preparation for the first finish coat.
It's crucial to apply the first finish correctly. Ensure that the surface is clean and dry before you begin the application. A brush is the most efficient way to apply the finish for even penetration. Apply the stain in the direction of the wood grain, completing only two or three boards at a time. Brushing on the finish in the shade slows down the drying time which reduces the lap marks. If possible, apply the finish to the sides of the boards for maximum protection.