While wood siding is a very attractive and durable siding choice, cleaning wood siding and preparing it for a fresh coat of paint can be a daunting task. By the time most people get ready to repaint wood siding, the old paint is starting to peel and chip away from the wood.
Because of this, the preparation process not only involves cleaning the wood surface, but often much of it has to be primed before the finishing paint can be applied.
Begin the task of cleaning the wood by going over its surface with a good quality scraper to remove as much of the old bubbled and peeling paint as possible. If the problem is severe, using a power washer to blast away the loose paint will be more effective and faster. Scraping will still be necessary after that the washing is complete because water never gets all of the loose paint to fall away.
Be careful when blasting the wood with the high-pressure water. The force of the water can easily begin to eat away the wood while leaving the loose paint. Also, avoid letting smaller children play with the power washer. The pressure is enough to damage the eyes and can even force water beneath the surface of human skin.
If an oil-based primer is being used, the wood surface must be allowed to completely dry. For a latex primer or finish paint, a little moisture does not hurt because the paint is water-based.
The areas of bare wood will need to be primed to seal the wood. If over 50% of the wood surface is showing, the entire surface should be primed to give a proper surface for the paint to bond. Generally, only one primer coat is necessary. It is not recommended that the finish paint be used for a primer. This is sometimes done on interior surfaces. The more porous wood surface needs a primer to seal it. The primer should usually be applied by brush or roller depending on the shape and condition of the wood.
The choice is up to the painter about how to apply the finish coat. Brushing, rolling, and spraying all have their advantages. Brushing gives a heavier coat of paint and allows for trim work to be completed as the job progresses.
Spraying gives a nice even finish, but it can require more coats to give the type of protection that a wood surface requires. Spraying also means that you need to do additional masking to prevent spray drifting onto windows and other surfaces. Wind can also be a problem when spraying. It is a fast way to get that surface covered.
Rolling is quicker than brushing and still gives a nice heavy coat, but it can be difficult if the surface is too irregular. Rolling also leaves more of the areas needing to be brushed after the main painting is completed. Rolling does have the advantage of leaving a smoother surface without all of the brush strokes just as spraying does, but it is not a problem in the wind.
Wood needs the protection of two full coats of finish paint. Sometimes even a third coat can be recommended.
Always make sure that the paint is applied on warm but not really hot days. Dry weather is best to let the paint cure properly. Do not try to wash the paint until it has dried for at least a week.