In the first example, a deck is power-washed with a bleach-solution. This will remove any dirt and grime in addition to mold and mildew from the deck. The power-washing will most likely raise the grain in the wood a little, so sanding is required. We like to use 80 or 100 grit sandpaper on an orbital sander and lightly scuff all of the deck surfaces. Not only will the sanding remove raised grain but will help the the new stain soak in evenly across the deck boards and railings.
Always make sure to let the deck dry a day or two in the sun after power-washing before sanding or staining.
The second example, we are using a more drastic approach to the deck refinishing. Here, we are stripping the previous coating off and starting new.
When to strip a deck? A: When the previous coating is peeling or wearing off unevenly. Or when switching from a solid-color stain to a semi-transparent stain.