How to Pressure Wash a House Before Painting It
Pressure washing a house prior to paint ensures a better, more even application

Giving a house a new coat of paint is a great way to update the exterior. However, your crew should never paint right over the previous layer. If your crew doesn’t clean the surface to remove dirt and grime, the new layer of paint might not stay in place.

Fortunately, cleaning the exterior walls doesn’t have to be hard or time-consuming. Find out how to pressure wash a house before painting it.

  1. Gather Tools
  2. Take the time to prepare for the job. Before you get started, you’ll want to have all the tools you need on hand.

    First, you need the right pressure washer. You’ll find gas and electric models, and both types can do the job. Gas-powered washers tend to have more power, but you don’t need much for this job. An electric model is your best bet for pressure washing siding.

    If you go for an electric model, you may need an extension cord or two. Make sure the cords you use are designed for outdoor use. Check to be sure they give you enough slack, too.

    Next, make sure you have the right nozzle. Many models include multiple nozzle tips so you can adjust the pressure and flow for the task. For most siding jobs, you’ll need 40-degree, 25-degree, and 15-degree fan tips.

    Finally, you’ll need a cleaning solution. Choose one that’s made for washing siding. It should be relatively gentle and contain no bleach, which can damage the washer and harm landscaping.

  3. Know the Risks
  4. Even if your crew has used a pressure washer before, your team needs to know the risks. Understanding the dangers in advance can help your crew stay safe and prevent costly damage to the home.

    Your team members should always use eye protection. Pressure washers can shoot water at a force that’s powerful enough to remove paint. That means they can also harm your crew’s eyes and skin.

    Your crew members should also know the right pressure levels to apply. If they use too much pressure, the washer could cause serious damage. Etching happens when pressure washers cut into surfaces. Since these devices have the power to create grooves in concrete, your crew should take care when cleaning wood or vinyl siding.

    Injecting happens when water gets under siding. High pressure can force siding to separate from the exterior wall. Excess moisture can also lead to water damage. Both can cause expensive problems for homeowners.

  5. Start With a Quick Clean
  6. When your crew is ready to begin, start with a quick clean. This first pass should remove all loose dirt and debris on the siding. Go over the entire exterior with the pressure washer. Make sure not to miss any areas that you’ll be painting over later.

    A 25-degree or 15-degree fan tip nozzle is ideal for this task. This type of nozzle will apply enough pressure and flow to clean the siding completely without causing damage. Always work from the top down to avoid injecting.

  7. Address Problem Areas
  8. After the first pass, allow the siding to dry. While your crew waits, they can prepare the cleaning solution and add it to the washer’s tank.

    Before applying the cleaning solution, your crew should replace the washer’s nozzle. Use a low-pressure nozzle, such as a 40-degree fan tip. Then use the pressure washer to spray the siding with the cleaner. Work upward for best results.

  9. Rinse Carefully
  10. After applying the cleaning solution to the siding, let it dry for up to 10 minutes. If the area your crew is working on is in direct sun, they should let it dry for less time.

    Next, empty the tank and remove the nozzle. Using clean water and a 15-degree or 25-degree nozzle tip, rinse the siding. Work from the top down and go slowly. This is your crew’s chance to remove embedded dirt and tough stains that could bleed through a fresh coat of paint.

    After a solid rinse, have your crew look over their work. They may need to use scrapers or other tools to remove stubborn spots.

  11. Allow the Walls to Dry
  12. After your crew has finished pressure washing, let the siding dry completely. Vinyl siding may be clean in a few hours. However, wood siding takes at least 48 hours to dry completely. Never paint over wet siding, as water damage could result.

    Once the siding dries, your crew can start painting. Since clean siding accepts paint better, you can look forward to a great-looking paint job.

Ready to get started? Rent the equipment you need to do the job right the first time.