Application Techniques
The first finish applied to cedar decks is the most important one. If the first finish is not done properly, it can be difficult to correct problems that develop later. The finish should be applied as soon as the cedar surface is dry. The deck should be cleaned, but power washing should never be used to clean cedar decks because this process can damage the wood surface fibers and make it difficult for the finish to bond. Factory finishing is the best option and is available in most markets.
Semi-Transparent Stains
Semi-transparent stains are best applied to decking by brush because the stain is worked into the wood surface promoting the achievement of even finish penetration into the wood. Apply the stain liberally by brushing in the direction of the wood’s grain. Apply finishes to the full length of only two or three boards at a time to avoid lap marks. Try to avoid overlapping areas that contain dry stain with fresh stain, which can also create lap-marks. Working in the shade can help reduce lapping because the drying rate of the stain is slower. Water-based stains are less likely to form lap marks than solvent-based stains because they are slower drying, but they form a thicker film on the surface than solvent-based stains and may not be as durable. Do not apply more stain than the cedar will absorb because the excess stain will appear as a shiny area on the surface. Apply the stain liberally to the end grain of deck boards, nail holes and any cracks in the boards. For maximum protection, deck boards should be stained on all sides.
Application of Transparent Stains and Water-Repellent Preservatives
The method of applying transparent stains to wood is similar to that described above for semi-transparent stains. Water-repellents, however, are more forgiving and can be applied by brush, pad, or roller followed by thorough back-brushing. Repeated brush treatment of Western Red Cedar until the wood will no longer absorb any more water-repellent (known as the point of refusal) will enhance the durability of the finish. The more water-repellent finish absorbed by the wood, the longer the service life. Liberal amounts of water-repellent should be applied to all lap and butt joints, edges and board ends. Other areas vulnerable to moisture penetration, such as nail holes and cracks also need to be well treated.