Most people who need to clean the outside of their home, a driveway, basement or have any other large outdoor cleaning project use a pressure washer that cleans by blasting away dirt and debris by using water that has been pressurized up to 5,000 psi or more. 

You can buy or rent a pressure washer and do the job yourself or hire a professional pressure washer.  In either case, however, it is easy to do a lot of damage to your home or commercial building with an ordinary pressure washer.  Water under very high pressure can very quickly damage siding, concrete, bricks, mortar, and stucco.  It can drive water underneath siding and shingles and can damage the glazing or seals around window panes, causing the window to leak.

Inflicting damage with a pressure washer is most common with inexperienced homeowners, but even a professional can create a lot of damage before realizing it.  To get good results with a pressure washer without causing damage you have use the right tip on the spray wand and use the least amount of pressure needed to get the job done. 

Even then, sometimes damage is inevitable. For example, if you are washing bricks with soft mortar, the amount of pressure needed to clean the brick could severely damage the mortar. 

Fortunately, there is a better way to clean large outdoor surfaces.  Low pressure washing uses environmentally safe chemicals to clean the surface, followed by a large volume of low pressure water to rinse away the cleaning solution along with the dirt and debris.  Low pressure washing techniques are safe for all surfaces and avoid the problems inherent with high powered pressure washers.