Soft Washing vs. Pressure Washing

soft washing gutters on a roof

It is shocking just how dirty the outside of your house can get over a year. Some of the most common stains include mud or dirt, algae, mold and mildew. These types of stains can give your house an unkempt, uncared for look, even though you invest time, money and care into it.

Some of these materials, like dirt or mud, are harmless, but algae and mold can be harmful to both your health and your house. They produce allergens and bacteria that can impact your family, and some, like algae, can grow directly underneath vinyl or roofing material and enter your house.

As a professional pressure washing company in St. Louis, we recommend you have your home’s exterior cleaned once a year. The spring season is typically the most popular time of the year to do an intense home washing, but you can really do it any time throughout the year so long as the weather permits.


All of the following home surfaces need to be pressure washed from time to time:

• Vinyl siding
• Rock and stone
• Brick
• Concrete and asphalt

Power washing used to be the only option to thoroughly clean vinyl, brick and painted home surfaces. Now, homeowners in St. Louis have another option for exterior house cleaning: soft washing.

As the names suggest, one method is a lot gentler than the other one, but there’s a little more to it than just that. Let’s review the features of each method to help you judge which one is the right choice for your house.


The soft wash system uses much less pressure than a typical pressure washer, hence the name. The maximum water pressure in a soft washing system is 500 PSI. This lower spray is produced from a nozzle with a wider spray setting, only a little more powerful than your standard backyard garden hose.

Soft washing uses a mixture of detergent, bleach and water in some combination to get rid of organic matter and debris from your home, roof and other exterior surfaces. The cleaning solution used in a soft washing system can include algaecides and residual inhibitors which will prevent further growth of these organisms in the future.

Because chemicals, not water pressure, are key to cleaning the surfaces, no powerful water is necessary. This means that soft washing can be used for delicate surfaces that would otherwise be harmed by more powerful pressure washing equipment.

The soft wash chemicals are sometimes washed off, but not always. This just depends on the type of chemicals are used in the process, if there is plant or animal life that could be impacted by the runoff, and if the solution itself is powerful enough to damage surfaces over time.

Soft washing offers the distinct advantage of reaching down into small cracks and crevices to kill unseen bacteria, meaning that its results can last longer than standard pressure washing.


Pressure washing has always been the gold standard for cleaning home exterior surfaces. It is highly effective and quick, which is why most home and business owners still prefer it.

This particular cleaning system uses water only, no chemicals, to remove stains and mildew from home exterior surfaces. The use of plain water is a significant advantage to home and business owners that don’t want to use cleaning chemicals, either for the sake of the environment or to avoid zoning violations.

The pressure washing process can be used on several different materials. Home and business owners frequently prefer pressure washing for cleaning their driveway, patio, decks, walkways and patio furniture because it is quick, efficient and cost-effective.

Pressure washing requires somewhere from 1300 to 3100 PSI water pressure with water sprayed out of a small nozzle for maximum power. Both organic and inorganic materials are sprayed from your home’s surface, prohibiting their growth and renewing the appearance of your house.

One negative about pressure washing is that the water can sometimes be too powerful and can damage the surfaces you want to clean. Pressure washing is powerful enough to put deep grooves in wood and plastic, and it can get into cracks, breaking off pieces of brick or stone.


The obvious question for homeowners is, “Which one should I choose?”

Both soft washing and pressure washing methods are good choices for your home’s exterior, including sidewalks, driveways and more. Both of these cleaning systems can be done by a professional – and truthfully, are more correctly done when left to the experts.

Soft washing is great for outdoor toys, yard tools, shingle roofs, decks, gutters, patios and painted surfaces because it is unlikely to damage wood and plastic. It’s also a safe choice for vinyl siding.

It removes organisms that are present on the surface, and it prevents future growth for longer than pressure washing can.

A disadvantage of soft washing is that it can kill plants underneath the surface you’re cleaning. Remember to spray them down with water before spraying the soft wash chemicals on your house or roof, and it shouldn’t be an issue.

Pressure washing is the preferred choice for severe stains, and hard surfaces like concrete, brick and stone. Pressure washing is the recommended process for commercial properties. A professional pressure washing company in St. Louis may use a mix of detergents and water pressure to eliminate tough stains, but they need to tell you if they are going to be spraying chemicals during your estimate.

It can be used for siding too (and has been for decades) so long as it is done correctly. High water pressure can break weak or smaller pieces of vinyl. A service that does pressure washing all the time will know how to protect weak pieces, but a DIYer could do a lot of damage.

Your home’s roof is off limits for pressure washing if there are slate, tile or asphalt shingles. The pressure of the water might damage these materials and require you to replace your roof far sooner than expected.

Deciding between pressure washing or soft washing is best left for a professional pressure washing company. Which process is right for your house? Give STL Pressure Wash Co. a call at 314-207-0443 and we will send a trained technician over to take a look!

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