Spraying from a ladder or at an upward angle.
Using a pressure washer from a ladder is obviously dangerous and not recommended. Even with a ladder, most of the time you still can't reach the high areas of your home without spraying the vinyl at an upward angle. Doing this forces water under and behind the siding. The weep holes on the bottom lip of siding are meant to drain moisture buildup, not large amounts of water. This leaves water behind the siding, risking water damage. Another trouble spot is the gutters and fascia areas. Dirt and moisture create an electrostatic bond to this type of metal. It takes the right cleaners and equipment to break this bond and get these areas clean again. Ignoring these areas altogether will be risking rot and decay of the wood and other building materials that make up your home. If your thinking about getting a power washing estimate, be sure to discuss these concerns with the contractor.