Everybody 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.
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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!
Founder & Editor-in-Chief
I love old houses, working with my hands, and teaching others the excitment of doing it yourself! Everything is teachable if you only give it the chance.
Thanks Scott for the insight! I agree this is a topic many pressure washing companies do incorrectly countless times. Even low pressure techniques on an older or softer surface can severely damage the surface of the structure. We specialize in everything from the commercial concrete parking lot cleanings to the delicate deck restorations. Appreciate the post! pressure washing
needs to be done right the first time before its too late!
There are numerous different reasons why individuals pick siding for their homes. Some need to enhance their home’s style while others get them due to their low support. Regardless of what the reason, there will come a period when you have to clean your siding which can gather lichen, buildup, form, green growth, grime, earth, and residue after some time.https://gearspick.com/best-vinyl-siding-cleaner/
Great and very useful information…
I just purchased an older home with aluminum siding can I use pressure washing to clean?
Pressure washing is rarely a good idea. But since we can’t see your home in person, our best recommendation would be to use our online directory to find a licensed preservationist in your area to see your home in person and provide a very accurate recommendation from there. thecraftsmanblog.com/directory
Best of luck to you!
-Alyssa at The Craftsman Blog
Hello Everyone, I’ve been Powerwashing Homes Exteriors for yrs. Never had one problem with anything I Powerwashed. I use a 3600 psi. You just have to be careful and pay attention . I use different sizes of spray degrees also. Depending on what I cleaning, that determines how close I place nozzle and angle..
I am a small business owner. Our business is run out of an old, brick building (constructed appx 1947) that desperately needs to be cleaned up. Discoloration on bricks/mortar. Several areas of mortar are clearly soft and crumbling, but this has not presented challenges to the structural integrity just yet. What is the best method to clean the exterior? Will power washing destroy this already weak mortar? Should I just invest in getting it repointed?
I would do a little testing first to see how the mortar holds up. Typically I will use a pump sprayer to apply a cleaner and then scrub with a firm brush (not metal bristle) and then pressure wash at a very low 1300-1500 psi rate. After ward you may need to repoint missing mortar.
Hi, I just purchased a old French Italian southern Manor style single story brick home built in 1925 with round pilars in front. I want to pressure wash the entire house, but before I do, I want to replace all rotted wood facial & trim, reseal roof shingles then pressure wash shingles, wrap entire perimeter of house with plastic up to 10 feet out , hand scrape large areas on Windows with heavy peeling paint then pressure wash Windows and brick after Windows have been recalled, broken glass repaired. I have a 1200 psi gas powered generac pressure washer. As long as I wear protective gear, use a low pressure setting to strip off remaining paint chips from Windows scraping won’t allow and ensure that no chips fall beyond plastic tarp and properly clean up and dispose of plastic containing paint chips. Is it better trying to restore old Windows and wood sills or is it better stop remove them all, dispose of them all properly, replace with new Windows & sills then pressure wash house. Is keeping old Windows & restoring old Windows better. Most all are painted shut, All have broken glass from vandals & all have heavy paint flaking which comes off easily. Any sugestiins.
I just purchased an old brick French Italian style single story home built in 1925. All the exterior windows have old heavy peeling paint with broken glass from vandals. I want to restore old Windows by fixing broken glass, recalling old Windows after glass repair. Cover entire yard with plastic 10feet out from wall and use a gas powered 1200 psi pressure washer to gently wash off old peeling paint with low pressure model, clean brick and wash roof shingles after revealing shingles. Wrap up plastic with washed paint chips in a plastic bag for disposal. Will this be ok to do as long as all paint chips are kept in plastic & bagged properly, or is better to scrap old windows, replace old Windows with new Windows & new wood sills then pressure wash house.
I have a house near the beach that has gray painted cedar shingles. I have stated to notice green mold on quite a bit of the shingles, and black mold on the white painted areas on the overhangs over the deck and entrance way. Having read all the posts, I am now very concerned about powerwashing — the house has never been powerwashed before. But I am also concerned about the mold and have noticed that the paint on some of the shingles has started to peel. Where do I start, and what do I do? Is there a time of year that’s best to do this? I am located in the Northeast.
Hello Meryl,
Thanks so much for writing in with your question. We are located in Florida so we totally understand the issues that can arise with homes near the ocean. Since we can’t see the damage in person, I would suggest using this directory to find a preservationist in your area who can provide a more accurate plan upon seeing the situation in person. But you’re right, pressure washing is often a bad idea so hopefully someone from the directory can formulate a great solution for you! https://thecraftsmanblog.com/directory/
-Alyssa at The Craftsman Blog
Meryl,
I would say that the terms ” Power washing ” or ” Pressure washing” today, are generic terms when it comes to washing most things. Usually pressure is only used on concrete or heavy equipment. When it comes to washing a wood sided house we in the wood restoration business let the detergents or strippers do the work for us. low pressure, or as low as pressure as possible , is used when it comes to removing the dirt, grime, mold, mildew, stain or other air born contaminants. Now of course we can only do what the wood allows us to do, meaning if the wood is old and brittle or falling off the house there really isn’t much one can do .
In your case, with painted cedar shakes , it is most definitely possible to wash your house and remove all the dirt, grime, mold, mildew and air born contaminants. By using the right detergents and low pressure an experienced power washer can bring back the youth to your home in just a days time. http://www.westernmainepressurewashing.com
My house is a high, old two-story wood house which has difficult access. The wood siding is not in good shape. The wood siding is warped in areas and has holes in it too like around the rusty nails. My house is about 85 feet long and very, very high. Due to caulking having worn off, some of the plaster inside one of the rooms in my house has fallen off, I guess from the wind and water from wood siding pieces that fell off.
My instinct tells me that due to the level of disrepair of my house i should not power wash it. It seems like there are too many openings where water could get in.
But my house is so high and long. such a massive area, I cant imagine what my roofer would say if i said not to power wash and to clean the wood siding by hand.
Doing it by hand he might not want to do because it seems that that would take forever.
Is it really necessary to clean wood siding first?
I just feel so torn. Roofers get aggravated with me when I say I dont feel comfortable with a power wash due to the poor condition of my wood siding.
Also, I think they would not agree to waiting a week after power wash to start painting.
Please help with any feedback!
Much appreciated.
Hmmm what an unfortunate situation!
Honestly, our best recommendation for you would be to use this directory to find a licensed preservationist in your area who would maybe be in network with a roofer who cares about preserving original materials and historic houses. https://thecraftsmanblog.com/directory
Best of luck to you!
-Alyssa at The Craftsman Blog
I had my house power washed recently and the spray got into the house around all of the windows (wooden windows) and onto the carpet and hardwoods inside the house in front of all the windows. Not good!
Oh goodness, so sorry to hear that! Best of luck to you and your projects in the future. Thanks so much for reading and commenting. We love to hear from people!
-Alyssa at The Craftsman Blog
Our building at work is being pressure washed. They didn’t tell us and did it on a rainy day. It wasn’t until I noticed all the paoer in my office was soaked looked out the window and a giant mist was coming around the building and into my window. We’ve all been very sick ever since. Eye sinus and breathing issues feeling very tired and worn out. Afrer reading your post, I’m wondering if there could have been chemicals in the spray.
Oh goodness, so sorry to hear that but happy that our post could help you possibly track down the issue. That’s definitely possible! I hope you all get to feeling better soon and that the building owner at the office hopefully learned a different approach for next time!
-Alyssa at The Craftsman Blog
You all inhaled spores or microorganisms. In addition to any toxins or particles from construction that were blown In and misted into the breathing air.
I am getting ready to sell my home. In need of a good cleaning with mold and grime (houston area), have had several quotes on the job. One was from a gentleman that steam cleans the home. He says that because he uses steam, it will not damage any area of my home. It was more expensive, but sounds like a better deal than the pressure washing in the long run. Does steam cleaning the home do as good of a job of cleaning as pressure washing? Would appreciate any guidance.
I’m a professional painter of nearly 26yrs. I’m also a Carpenter, Remodeler & owner of a small Construction company. I hold several certifications, License & continuously receive industry training regarding proper techniques, practices, etc. With that brief exposition of my background, I’m writing to respond to this article & clarify some unintentional incorrect info regarding pressure washing. Firstly, The MOST important FIRST STEP is understanding how to pressure wash CORRECTLY! That will LITERALLY AVOID Most of what the article mentioned as “what pressure washing causes”. Most of what is mentioned in the article is due to INCORRECT techniques RATHER than DUE TO PRESSURE WASHING. #1. EVEN IF water gets under the siding, that DOES NOT mean water WILL get into the home. Behind siding is “building paper” and or a water vapor barrier. THEN, behind the “building paper” is plywood. Therefore, water going under siding MAY NOT necessarily get into the home UNLESS, the paper is torn, AND the plywood has holes, cracks. There is a possibility, but a RARE possibility when pressure washing is performed CORRECTLY. The person who said water got in around windows = That has NOTHING to do with pressure washing! That’s IMPROPER window installation & flashing! RAIN water enters into improperly flashed windows. #2. Article said “Completely blast away mortar” on older brick homes. Firstly, even on older homes with “softer” mortar; INCORRECT pressure washing CAN remove some mortar. However, as mentioned, the pressure is shooting out water at 1500-3000psi. At that pressure, only a SMALL fraction of water can enter a Small opening created from missing mortar. A brief lesson in brick homes= There is a “cavity” or “Space” DIRECTLY behind the brick. It’s designed for water & moisture. Therefore, it would take A WHOLE LOT MORE WATER, than what would be caused from HIGH PRESSURE. Actually, a garden hose with much less pressure would cause MORE water to enter than a pressure washer. #Gouged wood = Again, even the Author acknowledged, INCORRECT PRESSURE WASHING as a cause for GOUGED wood, however Article stated 3000psi. You DO NOT pressure wash wood with 3000psi! Also, The UV Ray’s from the Sun causes “broken down paint residue” on the surface & you have oils, flaking etc that REQUIRES PROPER PRESSURE WASHING! More on this shortly. #4 Article stated “pressure washing causes LEAD BASED PAINT to be scattered around the yard”. ALL HOUSES DO NOT have lead based paint on the exterior. Also, EXPERIENCED, PROFESSIONAL PAINTERS “test” for Lead based paint PRIOR to painting! Lastly, Article mentions “low pressure options”. Article said regular garden hose & scrub brush sufficient. Remember, an exterior of a home takes A BEATING from the SUN, WEATHER etc. Earlier I mentioned “broken down paint residues”, OILS, & you have in some cases flaking, chipping. A REGULAR GARDEN hose DOES NOT have enough pressure to REMOVE most of what I just mentioned! Therefore, the new layer of paint WON’T LAST! Also, what if your house is a two or three story? You will need a PRETTY LONG HANDLE on that scrub brush!! I’ve painted for nearly 26yrs and NEVER had a call back due to water getting into a home!! Also, When remodeling AND performing Mold Remediation (I’m a Certified Mold Remediation Contractor) I see water damage caused more often from Rain, plumbing leaks,
roof leaks as opposed from pressure washing. I’m not saying pressure washing NEVER causes water to enter a home, However, in nearly 26yrs of painting, remodeling, I personally have NEVER caused OR repaired a home due to Pressure washing! I THINK THAT SPEAKS VOLUMES AS TO THE “SLANT” OF THIS ARTICLE REGARDING PRESSURE WASHING! PROPER PRESSURE WASHING IS HIGHLY EFFECTIVE & NECESSARY IF YOU WANT YOUR EXTERIOR PAINT JOB TO LAST! NOTE: There are ALWAYS extenuating circumstances. I feel pressure washing getting into a home is MORE exception THAN RULE.
Would an electric pressure washer (like the ones they rent at home depot) be enough to clean a cinder block wall around the property, prior to painting? How about a concrete patio? I’d rather not use the medium gas one if possible. I’ve tried cleaning the cinder block with a scrub brush but that didn’t do anything.
Thank you!
Had house power washed by painter and left Windows a mess. Should he have cleaned or rinsed those . Never thought to ask
Only one causing damage to a house is the guys not knowing what they are doing, pressure washing companies have moved to soft washing houses because of many reasons. It is still very safe to wash a house with no signs of damage being done. Just have to stop hiring those 99$ house wash guys ,
This is great information! Thanks for sharing it. I live in a mobile home and was considering having it pressure-washed. Thanks to you, I now know better than to do that. Getting my elbow grease ready to go….
So glad we could be of help and help preserve the integrity of your home! Have a great week!
-Alyssa at The Craftsman Blog
You can have it soft washed this guy really does not know that much about what hes talking about.
My house is white brick and it was pressure washed. The brick was washed so hard that the white coating on the brick was washed away in some areas. Now some bricks are the yellowish color with no white color. How can I get the white color back?
Depends I have cleaned brick for 20 years, most white brick is super soft and has to be washed with very low pressure to protect the integrity of the brick, very easy for someone to blow the face off if they dont know anything. Stains depends on what they used ? Certain acids can stain white brick , they do make a product called 800 stain remover that works against alot of stains
Know the best option is to leave your house green and have black mold all over
The truth is you should never pressure wash your house, but everyone does it. Learn why you shouldn t right here!
You make some valid points but I dont completely agree. A correctly done pressure cleaning job can extend the life of a home.