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4 Reasons You Should Never Pressure Wash Your House

4 Reasons You Should Never Pressure Wash Your HouseEverybody pressure washes their house. But few people know that the way it’s usually done is NOT good for your house.

You may just be going with the crowd, but in this case, the crowd is wrong, and you’re likely causing big damage that you have no idea about.

Pressure washing is usually the first step in getting a new paint job, so I see a lot of painters doing it and doing it wrong.

It’s not just unknowing homeowners doing this, it’s the professionals as well! Painters and pressure washing companies walk away from a house with a clean exterior, but the work they did has caused untold damage inside the walls of the house and other places.

There are four main reasons you should never pressure wash your house. Four ways that pressure washing does more harm than good. At the end, I’ll discuss the right way to way wash the outside of your house, but first the bad way.

Reasons to NOT Pressure Wash

#1 Water in the Walls

To me, this is the worst kind of damage you can do with a high pressure washer to a house. Commercial pressure washers shoot water at pressures starting at 1500 psi which isn’t too destructive, but they can go upwards of 3300 psi, which will blast through solid wood, asphalt, and even concrete (I’ve done it) if they’re close enough.

If you have a wood frame house with any kind of wood siding (clapboards, shiplap, board and batten, shingles, etc.) there is an excellent chance that washing your house with a high pressure washer will shoot water up under the siding, potentially soaking wall cavities, insulation, wiring, flooring, plaster, etc. Nothing is beyond the reach of these powerful water guns.

[Tweet “Your house is full of gaps and cracks and high pressure water will always find its way in.”]

Once the water is in the wall, it is often difficult for it to evaporate. Often, in the painting process, a house is pressure washed, then caulked and patched and finally painted. Essentially, the painter is soaking the inside of the walls and then sealing the water in with a fresh coat of caulk and paint.

I have seen moldy insulation, crumbling plaster, and cupped flooring all from a pressure washer’s work. Nothing in your walls likes to be wet so keep it dry.

#2 Missing Mortar

A lot of people think that since they have a brick house, they are safe to pressure wash. Think again! Old brick and mortar are softer than the new stuff today and can be easily blasted away with high pressure water.

I’ve seen brick houses with the mortar almost completely blasted away by pressure washing. And the expense of repointing a brick house is probably 10 times what the pressure washer charged you to wash your house.

#3 Gouged Wood

When pressure washing, a lot of painters will get right up close to the surface to try to blast loose paint off. They often succeed and then that 3000 psi water is blasting right into bare wood. It digs holes in the surface and furs the wood grain up damaging the siding.

Unless you’re into carving your name into the side of your house with water, this is yet another reason not to pressure wash.

#4 Lead Paint

It’s always there lurking beneath the surface on an old house. We all want it gone, but removing paint with high pressure water is not the solution.

It causes lead paint chips both small and large to be blasted all around the yard and get mixed into the soil where the kids can potential ingest it.

If you don’t have kids, think about the neighbors or the next folks. Lead paint is everyone’s responsibility. Read more about lead paint safety here.

When You Should Pressure Wash

Don’t think that I am against pressure washers. They are a great tool, I just see them being misused way too often. There are times and projects where a pressure washer is the best tool for the job and I want to be sure to mention those as well.

Some projects work best with high pressure (2000-3000 psi) and others with lower pressure (1250-2000 psi)

  • Decks (Low pressure)
  • Railings (Low pressure)
  • Wood Fences (Medium pressure)
  • Vinyl Fences (Medium pressure
  • Asphalt (Medium pressure)
  • Concrete Driveways & Sidewalks (High pressure)
  • Metal Patio Furniture (High pressure)
  • Stone and Pavers (High pressure)

So, if pressure washing is dangerous for your house what can you do to get things clean?

The Low Pressure Option

I’ve found that using a homeowner grade pressure washer allows me to safely wash a house with the pressure low enough to be relatively safe and I’ve outlined my methods in an earlier post Pressure Washing an Old House.

Ultimately, the safest way to clean and prep the exterior of your old home (especially wood houses) is to use a regular garden hose and spray nozzle along with an extension pole with a nylon scrub brush.

It takes longer, yes, but it actually does a better job at cleaning the house and preparing for paint in addition to being a hundred times safer for your house.

I’m not sure how many of you will follow this advice, but I would be remiss to not tell you the dangers. What you decide to do with the information is up to you!

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154 thoughts on “4 Reasons You Should Never Pressure Wash Your House

  1. We all must opt for the best pressure washing service for our home occasionally. In this article, the writer has strongly focused on all the major reasons that we must consider for our home pressure washing. This article is very useful for us.

  2. The best part of this article is that it allows for comments so we can get the point of view from the author and then here differing views from commenters. So we go away having more information from which to make our own decision. I usually find the truth is somewhere in the middle between 2 opposite sides of the continuum. I thank the author and the commenters and found a lot of good info on both sides. Bottom line, go with an experienced and knowledgeable painter! One you’ve seen his work personally, after time has passed so you can see it has lasted well. And always ALWAYS never trust a painter who says you do not need to prime raw bare wood, wood that has never been painted before. I have met a few in my quest to find a good painter. Not priming bare wood that has never been painted before (like fascia) is an alarm for me much more than the power wash–if done by a painter that knows what he’s doing. I learned the hard way and had to replace almost all my fascia after only six years.

        1. Do you ALL use rotating tips? Funny because I see the damage all the time from overly aggressive pressure washing so somebody isn’t using the right tip or pressure.

  3. I live in an Orwellian Big Brother HOA subdivision where neighbors literally walk around and take notes of everything wrong with the houses and yards. One man is complaining because people don’t pressure wash their houses, so now I’m freaking out. I was researching when I came upon this information. Now I’m even more confused than ever. I want my house to look good, but I don’t want to damage it. I have a horribly white house (love the house, hate the color) and I’m not even sure what siding it is. My husband is disabled, so I’m not comfortable with many DIY options. This makes me not want to pressure wash, but I live with the constant stress that my house/yard won’t be perfect enough for the analy retentive HOA board.

    1. Thanks for your advice. My neighbor just power wash her house and I was tempted to do the same but wasn’t sure. But now I will not do it.


  4. I’m a professional paint contractor and have been in business 26 years, specializing in both exterior and interior painting. I’m sorry but I’m going to disagree with you. If you want to extend the life of your paint you need to pressure wash at least every two years. Mildew is attracted to dirt, dust, pollen and any other atmospheric contaminants that are on your homes substrate. These contaminants serve as a food source for mildew and once the mildew has eaten through the contaminants, it starts to eat your painted surfaces. Shooting water in to interior walls is false. If you know what you are doing, or you hire a professional, you don’t have to worry about this. Damaging mortar? No, not unless the mortar is in terrible shape already and if it is, you need to have your brick repointed. Light pressure is fine for some areas but if it’s a two and three story house, light pressure will not do a thing to remove dirt and debris. A clean house is generally a well maintained house.

    1. Y’all know you can soft wash with a pressure washer? Safest and most effective way to get all the algae dirt and grime off the exterior of a household and can also be used for roofs, gutters, fences, decks, porches, and fascias.

    2. I have had good success with adding a mildewcide to all the paint that I use on the exterior of a house. This costs me about $5 extra per gallon, which some people would consider a lot. I don’t. I add it to paint even when the label says that the is mildew resistant or that the paint contains a mildewcide. If a house already has mold or mildew, I clean the compromised siding twice, but never using a pressure washer. I use a cleaner designed for killing mold and mildew. I don’t use dish soap or TSP or the usual detergents. I usually only have to do this to the north side of a house. No pressure washer for me. Mold and mildew just blows around in the wind. It will be back.

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