Why You Should Never Pressure Wash a Home





Pressure washing has caused countless leaks, probably millions in damage and major headaches for homeowners looking to keep up the appearance of their home. Pressure washing a home, is the process of using water at 2500-4500 pounds per square inch to remove algae, mold, dirt and black streaks from a home’s siding and gutter line. If you think your insurance will cover damage of this sort your wrong!

Gradual water damage is an example of something that is not covered under a homeowners insurance policy. Many homeowners don’t realize this before it is too late.

This method has been used for decades by inexperienced homeowners and faulty contractors to give the home a quick inexpensive makeover, without the added expense of repainting the surface. Although pressure washing a home can in many instances completely rejuvenate a home’s appearance, the method of pressure washing is far more important than the actual finished product for several reasons. In the post we discuss our method for softwashing houses in Renton, Seattle and Shoreline, Washington. 



WOOD FURRING-1A pound per square inch is the amount of force water is delivered to a surface. Typically to be effective a pressure washer must deliver between 2500-4500 PSI to remove dirt and algae from wood and other structures.

The force of 4500 PSI is enough to tear and rip human skin and it does equally as bad against wood. Most woods used in exterior surfaces are porous woods such as Douglas fir and cedar. Cedar is moderate softwood and one of the most popular woods used in the Pacific Northwest.

Cedar is used in countless homes siding, decking and roofing in the greater Seattle area. Cedar cleans up beautifully when maintenance is done; correctly. However what cedar and most woods can’t stand is pressure blasting away its fibers and creating furring. Check out our blog post on wood restoration here. 

Furring is the lifting of wood fibers, typically caused by excessive pressure. Furring exposes and damages a wood surface and causes irreparable damage to a wood structure. The only option once furring has set in is to either sand the surface or steel wool it, causing even more damage and material removal to the wood structure! 


high-pressure-siding-damageOnce again, 2500-4500 PSI blasting away at any surface is not good. It is an extremely bad idea to use that much pressure on materials that overlap such as siding and roofing. The overlap of siding is designed to stop water from ever getting behind the siding and destroying the paper, wood and insulation behind it.

Water always travels down siding and roofing. Using a pressure washer at excessive strength pushes water up siding and roofing. The initial design of the material was made to prevent that from ever happening and for good reason.

Once water gets behind siding the amount of damage to the structure starts to add up rapidly. The paper behind the siding is now wet, without being able to dry , it begins to create mold, the mold then rots the wood behind the paper, once that happens the insulation begins to carry the mold and create moisture. After repeatedly taking on moisture from a failed building envelope, the insulation passes on the mold to the drywall, floors and structure. What is left is, tens of thousands of dollars in damage when a water intrusion is not caught in a timely fashion. Only certified plumbers may provide immmediate residential cleanup and repair in such cases.



A technician performing the soft wash method on a roof.

You would never wash clothes or dishes without soap. Why would you wash a house without it? Although this sounds pretty simple, we at PWNG have seen the disastrous effects of the use of a pressure washer in the wrong hands. Not only can a pressure washer destroy a home, but incorrectly mixing chemicals or not rinsing properly can as well.

Most times the issue of chemicals not performing is user error. However after personally having tried dozens of chemicals on the market sold at Home Depot and Lowes, I have come to the conclusion that most of the products on the market today are not effective for properly cleaning a home. 

The Western Washington areas including Renton, Shoreline, Seattle are new to this method of power washing homes but it is not a new method. This method of soft washing has been a standard practice all along the East Coast , where the founders of PWNG are from. We have been strong advocates and pioneers in the chemical method of correctly cleaning a home’s siding to this area .  We take great pride in having changed the culture of this areas method of house pressure washing. 

chemical icon

click for the chemical list

After scanning through several of these products MSDS and ingredient sheets, what became obvious is that in most commercial house wash mixtures the ratio of water to the actual cleaning product approached 85% and as high as 96% water with only 4-15% of the product containing the actual cleaning agent! In short: a watered down ineffective cleaning solution.

In summary, pressure washing can be a blessing or a curse. The experience of the user is the key component in either cleaning a home or destroying it. Store bought chemicals and user error are contributors to a lack of experience but they are not the sole cause of water damage and chemical damage to a home.




Algona, Auburn, Beaux Arts Village, Bellevue, Black Diamond, Bothell, Burien, Carnation, Clyde Hill, Covington, Des Moines, Duvall, Enumclaw, Federal Way, Hunts Point, Issaquah, Kenmore, Kent, Kirkland, Lake Forest Park, Maple Valley, Medina, Mercer Island, Milton, Newcastle,Normandy Park, North Bend, Pacific, Redmond, Renton, Sammamish, Seatac, Seattle, Shoreline, Skykomish, Tukwila, Woodinville, Yarrow Point