How to power wash your home safely: A beginner's guide

Key takeaways

• Power washing and pressure washing are not the same thing. Both use high-pressure water to clean surfaces, but power washing adds a heating element.
• Some surfaces should never be power or pressure washed. Laminar sandstone is too soft to withstand the force, while asphalt roofing will lose its protective granules and can be destroyed.
• Safety precautions are essential because the water stream can exert up to 2,000 pounds of force. Never aim the sprayer at another person or electrical and water outlets.

Power washing and pressure washing use high-pressure water spraying to clean surfaces. The terms are similar, but the fact is they're two different processes. Both use water under high pressure to clean surfaces, but power washing has a heating element that pressure washing does not.

The idea of a good steam cleaning of your house, deck, driveway or other household feature is appealing. Hot water shot through a high-pressure hose will take off just about the most stubborn dirt and stain. But it's not really the best choice for things like brick, concrete or masonry. Power washing can be very harsh on those surfaces. Use a pressure washer with an appropriate cleaner instead.

• Use for large areas like extra-long or big driveways.
• Use where you have extreme dirt, grease, moss, weed buildup and slick surfaces due to mold. The heated water can loosen up stuck-on grime outdoors just like hot water cleans dishes and floors better than cold. It also kills mold and moss and prevents their quick return.
• Use power washers on hard surfaces that can stand up to the heat and pressure

• Use for small patio, deck or driveway areas.
• Use for softer surfaces, like wood decks, siding and tiled areas.
• Use on areas like masonry, concrete and brick.

Understanding the difference among cleaners can mean the difference between cleaning and destroying what you are power or pressure washing.

There are specific soaps for driveways, concrete and wood. Make sure you get the right cleaner for what you want to clean. You can get things clean with just a power wash and water but think about how much better any surface is cleaned by using hot water and soap and pressure.

Not all surfaces should be washed. They include:

• Laminar sandstone — it's too soft a material to power or pressure wash.
• Anything painted — while painted items can be washed, it usually takes a pro to do it without destroying the paint.
• Asphalt roofing — power or pressure washing will take the granules off of an asphalt roof and literally destroy it.
• Anything old — furniture, decks, wood buildings, etc. may have dry rot that will disintegrate under a pressure wash. Even good wood can be soft and damaged by a pressure wash.
• Stained wood — pressure or power washing can literally take the stain right out of wood. If that's what you want, go ahead, but if it's not, remember you may need to re-stain the wood once it's dried.

Since the primary or only difference between the two methods is heat, it's important to consider the size of the area you'll be cleaning, as well as the type of surface you'll be cleaning. The main benefit of using hot water is that it's a much more efficient and effective deep clean when compared to unheated water. Heated water is a better cleaning choice for larger areas.

If you're a hardcore do-it-yourselfer, then consider renting a commercial power washing machine rather than buying or using a home unit to clean large areas. Better yet, hire a professional. Whether the unit is a home or commercial unit, in the hands of an untrained homeowner you can either damage the thing you're cleaning or leave obvious cleaning lines that can mar the appearance of the item. You can also damage the power washer or hurt someone.

Power cleaning can be dangerous. The force of the stream can be up to 2,000 pounds and break apart concrete and stone.

• Never spray a power/pressure washer at a water or electrical outlet. Secure or cover all water and electrical outlets before spraying.
• Never spray a power/pressure washer at another person — the spray can seriously hurt or even kill them.
• Use safety glasses, goggles or a full-face shield when spraying.
• Close range is great for some applications but stay at least five to six feet away from the surface you're cleaning until you know how the spray reacts.
• Start with the lowest setting possible and test it on a hard surface before spraying windows or soft surfaces.
• Start from the top of a vertical surface and wash your way down so your dirty water isn't cascading over clean areas.
• Spray first with a chemical or cleaning solution and let soak for five to 10 minutes, then immediately rinse with clean water. Don't allow the cleaning solution to dry on the surface as it simply redeposits dirt you loosened initially. Spray it with an ordinary garden hose to keep it wet or moist while it's soaking.
• If you're renting the unit, ask the shop or clerk to demonstrate how to use the unit and not just explain its operation to you.
• Make sure you're using the correct nozzle for the job you're doing. A 0-degree nozzle has the hardest spray and is best used for clumps of dirt, algae, mud and stains. A 40-degree nozzle sprays wide and is best used for house siding, sidewalks, patios, decks, etc.

Most power/pressure washing is done in the fall or spring. If you do get a few warm days in winter, check the weather forecast. Shooting water into cracks and crevices is fine in warm or cool weather, but if you're expecting freezing weather within a few days to a week of pressure washing be aware that water may freeze and expand, damaging what you've cleaned. Make sure that temps won't drop below freezing before you wash.

More on this topic:

• How to improve your home's curb appeal before selling with easy fixes
• How to prepare your home for sale