Pressure washing, also known as power washing, involves using a high-velocity water spray to clean dirt and residue from the exterior of a house. This type of cleaning is a particularly important preparatory step before painting or re-painting your house. A clean surface allows new paint to last longer. You can use pressure-washing equipment on most types of housing material once you learn how to pressure wash a house.
Choose a pressure washer that is best for the job. Different housing materials can withstand various water pressures. The size, or spray power, ranges from 1,200 to 3,000 pounds per square inch (psi).
Softer housing materials, such as painted soft-grain wood and aluminum, require a 1,200 to 1,500 psi model to prevent pressure damage. You may need a wide spray nozzle to disperse water pressure for even more vulnerable materials, like stucco.
Stronger non-painted surfaces, such as vinyl, clean better with a more powerful 2,500 to 3,000 psi model. These models work the fastest.
Select a pressure washer that has a detergent dispenser if you plan to use a cleaning solution.
Protect you house’s exterior fixtures, like lights, landscaping shrubs and plants, from harmful water pressure. Cover with drop cloths or plastic covering and secure with duct tape.
Manually scrub any visible mildew from the surface you are power washing with a brush.
Mix the cleaning solution and fill the pressure washer’s detergent dispenser. Combine approximately 1 pound (.455 kilograms) of a non-phosphate concentrated cleaner for every 4 gallons (15.4 liters) of washing water.
Connect a garden hose hooked to your water supply to the pressure washer. When you are ready, turn on the water.
Test how to pressure wash a house by holding the pressure washer nozzle with both hands about 3 feet (121.92 centimeters) from the wall. Move it in closer until you feel the spray is strong enough to remove dirt but not strong enough to cause damage.
Start at the top of the house and move down. Spray roof overhangs, under-hangs and gutters at an approximate 45-degree angle. Move the spray steadily from side to side.
Rinse from the top down with plain water from a garden hose. Allow house siding to dry at least 2 days before painting.