Important Considerations

Whether hiring someone (or doing it yourself) it's important to avoid damaging the area being washed.  This is not a good job for Rambo wannabes. While a power washer can be fun it is prone to causing damage if not done carefully.

Common mistakes include washing siding from ground level (which injects water under siding and into vents leading to potentially serious issues) or getting too close to the surface (a powerwasher can easily plane down deck planking).

Unless done by an experienced user or a very cautious novice any surface can easily be left uneven, requiring extensive sanding to restore it back to being a flat board.  If doing it yourself start on an area that is not easily visible so you can get a feeel for the unit you're using.  A power washer can be rented at Home Depot for about $50-$75 a day.

Another equally important part of preparing surfaces for paint or stain is using an environmentally safe house or deck cleaning solution in tandem with the powerwashing to achieve optimal results.  This requires a deck or house cleaning brush (they are different) to remove soot, grit, mold, and mildew.