How To Pressure Wash Your Home

Has your home exterior seen better days? Have cobwebs, grime, and bird droppings turned your siding into a dirty mess? Or perhaps your house has been the same color for as long as even your oldest neighbors can remember and you’re due for a change.

Whether you intend to merely clean it or prepare it for a new layer of paint, pressure washing your home can make the job just a little bit easier. However, if you don’t know what you’re doing, it can also create a disaster.

The Pros and Cons of Pressure Washing

Sure, pressure washing your exterior offers some benefits, but it can have definite drawbacks and risks, as well.

Pros of Pressure Washing

On the bright side, pressure washing helps remove contaminants that may be adversely affecting your family’s health, poisoning the environment, or accelerating the deterioration of your siding. Pressure washing also adds curb appeal that can increase the value of your property.

After a session with the pressure washer, you may even decide your paint job is in better shape than you thought. Best of all, renting or buying a pressure washer offers high value at a relatively low cost. Use it to remove the finish on your deck, clean your concrete, wash patio furniture, and more. (Your friends and neighbors will probably want to borrow it too).

Cons of Pressure Washing

For all the advantages, however, pressure washing has potential hazards, too, so keep in mind:

  • Pressure washing involves water emerging from the machine with extreme force. The water pressure is hundreds of times greater than that from the typical garden hose. It can cause siding damage, shatter windows, erode brick and mortar, and do structural damage.
  • Not only will pressure washing help strip paint and clean debris, it may also drive the water deeper into soft wood. The harshness of the action, plus the high moisture content now inside the wood, can create damage and lead to rot. At the least, it requires longer to dry before you can repaint it, compared to a manual washing of your home.
  • Along the same lines, if water penetrates between the siding and trim or manages to get sprayed up under the bottom of the siding, it can leak into the house framing. Once wet, mold and rot have a standing invitation.
  • No matter how thoroughly you do it, you can’t expect power washing to remove every bit of peeling paint and every trace of dirt. There’s simply no substitute for hand scraping loose paint after the wash, and scrubbing dirty siding during the process.

    That said, pressure washing can be useful, as well as safe, when used by the right hands. However, you must know how to use the pressure washer properly, what to do to safeguard your house during the washing, and most of all, don’t expect the pressure washer to do all the work for you. It’s mainly in the inexperienced hands of novices that damage is likely to occur.

    Getting to Know the Pressure Washer

    Before you do anything, familiarize yourself with the equipment. Understanding how it works and getting comfortable with it before you turn it on your house helps prevent accidents. Ask the sales or rental clerk to explain how it works, and completely read the instruction manual.

    Pressure washers are either gas-powered or electric. Electric models are generally weaker – you may not get the water pressure you desire (although you are also less apt to accidentally damage anything). The water emerges from the spray nozzle under tremendous pressure, controlled by an adjustable regulator.

    The highest settings – typically 2,000 to 2,500 pounds per square inch of force – are generally reserved for stucco and other uses. For exterior siding, try setting it to anywhere from 800 to 1,500 psi if you’re cleaning wood, vinyl, or aluminum – brick requires a slightly lower setting.

    Also, familiarize yourself with the tips that come with the machine. Each color corresponds to a suggested surface, typically green for all-purpose cleaning, white for gutters, yellow for concentrated power, and red for metal or concrete.

    Safety Tip: Speaking of focused power and the force with which the washer operates, never point or allow the pressure washer to be aimed at any person or animal. At even lower pressure settings, the water is strong enough to seriously injure. At higher levels it can prove lethal.

    Before You Spray: Preparing for Pressure Washing

    Take a walk around your house before you start pressure washing. Look for signs of decay. Rotted materials may be so soft that they crumble under the force of water. Note that vulnerable windows may shatter when sprayed. Look for leaky windows, missing trim, and other problem areas. Fix problems, where practical, before spraying.

    Next, protect your house by taking a few precautions:

  • Close all windows and doors. Consider taping thick plastic sheeting over vulnerable glass to help protect it.
  • Spread plastic sheeting over the plants and flowers you wish to protect.
  • Clear the surroundings of any patio furniture, as well as items that may get destroyed or prove a dangerous obstacle.
  • Turn off the electricity to any item in the washing area.
  • Cover exterior electrical outlets as well as any pipes, wires, or other openings through the home wall with plastic sheeting.

    A Word About Pressure Washing With Cleansers

    You don’t need expensive cleansers and fancy techniques to get your home clean. Instead of using a commercial pressure-washing cleanser, try one of these two homemade solutions:

  • For a general cleanser, add ½ cup tri-sodium phosphate or laundry detergent to 1 gallon water.
  • To combat algae, lichen, mold, and mildew, mix 1 quart household bleach and 2 ounces TSP or detergent with 3 quarts water.
  • Use a stiff-bristled brush and work the cleaner into the siding or exterior surface. For stubborn stains and contaminants, consider coating the surface with a thick layer of the cleanser and covering it with plastic sheeting for an hour or two to create a poultice. Rinse away, then continue spraying and scrubbing as necessary to finish your home’s exterior.

    Safety Tip: Enlist a helper not only to make the job easier but safer as well. Your assistant can help stabilize the ladder, when needed, and scrub the surfaces with long-handled brushes or brooms.

    Using the Pressure Washer

    Always wear long sleeves, gloves, and safety goggles while pressure washing any item. When working on a ladder, keep one hand on the ladder at all times; the pressure washer can produce quite a kick that may knock an unwary user off the ladder.

    Using the pressure washer is quite simple:

  • Prepare the pressure washer. If it’s powered by gas, check and fill the fuel and engine oil as needed. Lubricate the pump with 30-weight oil or as directed by the manufacturer.
  • Choose the desired nozzle and attach it. Make sure it’s secure to prevent it flying off during the washing.
  • Connect the hose that supplies the washer with water.
  • Turn on the water supply. Avoid using the water inside the home for the duration of the washing.
  • Pull the washer’s trigger to expel air trapped inside it. Watch for a steady spray of water; when it appears, turn the washer on.
  • Squeeze the trigger as far as it allows so as to avoid harming the pump. This is particularly important with gas-powered power washers.
  • Sweep across the top of each exterior wall, aiming the spray of water down toward the ground, never up. Spray as far as your arm will reach before working down the wall, spraying, scrubbing, and rinsing.
  • Move to the next section along the wall and repeat. Spray at the top of the wall, scrub, rinse, and work downward. Keep the nozzle approximately 3 to 4 feet from the surface at all times to avoid damaging the material.
  • After pressure washing your house, leave adequate drying time if you intend to paint. Under average conditions the exterior will dry in a day or two. In rainy or humid weather, it could take a little longer.

    Safety Tip: Don’t pressure wash your house if you suspect it was painted before 1978. Prior to then, lead-based paints were commonly used. Take a paint chip and have it tested for lead if you have any doubts. Lead paint must be hand washed instead. For more information, contact your local health department or call the EPA at 1-800-424-LEAD.

    1 Comment

    • Bruce September 21, 2014 at 6:24 pm

      I agree with spraying down the wall (you don’t want to spray water up under siding & flashing), but I disagree with starting at the top of the wall.
      My experience is with washing interior walls. If you start at the top, the dirty water running down absorbs into the wall, carrying in dirt. You wind up with a streaky wall. If you start at the bottom, then water running down is running over an already saturated surface, and does not leave streaks. I would expect the same issue with exterior cleaning.


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