Soft washing is a way to clean using chemicals and a large volume of water, instead of pressure, to wash something. It’s a popular way to clean the exterior of a home to avoid damaging siding and other components of the home that are easily damaged by high water pressure. Let’s dig into exactly what you should soft wash vs. pressure wash on your home.
Pressure Washing vs. Soft Washing
Fist things first, it’s useful to understand the difference because a lot of people as this question and there aren’t many good answers out there. Soft washing is accomplished by applying a chemical solution to a surface and rinsing it with water, whereas pressure washing relies on the water pressure alone to do most of the cleaning.
But both methods are done with a pressure washer most of the time.
In fact, I’d go so far as to say that soft washing is a method of pressure washing. Without the pressure.
Granted, some professional outfits may have a machine they use for specifically soft washing that specialize in high volume, low pressure water streams. A “soft washing machine”.
But most home owners can achieve the soft washing effect with their pressure washers. It’s usually done with the widest angle tip that comes with the pressure washer. Whatever setting that gives you the lowest PSI, with the highest volume of water.
There are also some good pressure washer guns that have adjustable PSI
Chemical Soft Washing Mold, Mildew & Algae
Soft washing is effective in situations where killing mold or mildew is part of the cleaning process. Most soft washing techniques involve applying a 12.5% bleach to water solution to a surface and allowing it so sit for several minutes before rinsing. This kills mold, preventing it from returning more effectively than using water pressure alone to remove it.
The Safety Benefit of Soft Washing Hard to Reach Areas
Soft washing hard to reach areas that would otherwise require a ladder is a great safety benefit. This is one case where you can use a high pressure tip on your pressure washer to soft wash those hard to reach areas. No need to take the risk of personal injury by climbing up a slippery ladder to scrub under the awning of your second story roof.
Just be sure you don’t accidentally hit your siding up close with the high pressure tip. The delicate siding can often get damaged by the high pressure streams from a pressure washer.
7 Things to Soft Wash on Your Home
Here’s out list of 5 things you might be wondering whether you should pressure wash or soft wash on your home:
1. Solar Panels
Solar panels are comprised of delicate materials that can easily damage under the PSI of a pressure washer. It’s much better to take the soft washing approach for this reason. Not to mention they are often found on the roof of most homes which can be hard to spray down directly.
Unlike other parts of your home, however, solar panels can be damaged by harsh detergent such as bleach. It’s recommended to mix a solution of window washing liquid for solar panels for the initial spray. Mix window washer and water at a 1:1 ratio and apply.
Wait 10 minutes, then rinse thoroughly with water. You don’t want to leave a soapy residue that will attract more dust and pollen.
2. Hardie Board
Hardie board is a durable siding that’s made from cement, sand, and cellulose fibers. It’s also something that can deteriorate from repetitive pressure washing. Definitely something you want to soft wash on your home.
When washing hardie board and other sidings on your home you want to determine what it is you’re trying to remove when washing it. Is it dirt or is it something a bit more stubborn like mold? If it just dirt you can soft wash it with mixture of soapy water in your pressure washer’s detergent tank. A tablespoon of dawn with a gallon of water will do just fine.
If it’s mold or algae, try a mixture of 12% bleach with water. This will kill the mold and help prevent it from coming back. Spray your bleach mixture with a wide angle tip. Wait 10 minutes then rinse with pure water using the same wide angle tip.
3. Windows & Window Frames
Windows and their frames are some of the most delicate parts of a home. The sealant that’s used to install windows to the frame can easily be stripped under the intense water that comes from a power washer.
Furthermore, that same sealant is prone to attracting mold and mildew. Windows are a perfect candidate for a soft wash using a 12% bleach to water solution for the first rinse. Wait 10 minutes, then rinse with a wide angle, low pressure tip on your pressure gun.
4. Metal or Wood Roofs
It’s not recommended to pressure wash metal or wood roofing for different reasons. Wood roofs are delicate and the individual shingles can become displaced under a relatively small force. Certainly a powerful pressure washer can damage them.
Metal roofs are dangerous to walk around on, especially when they are wet. It’s much safer to clean your roof from the ground if possible.
For those reasons it’s better to soft wash your metal or wood roof with a primary solution of 12% bleach to water. Use a narrow angle tip if that’s what’s needed to get the application onto the roof. Just be careful not to spray any other areas of your home with that tip. Wait 10 minutes then rinse thoroughly with pure water.
5. Hard to Reach Awnings
If you have a multi-story home, those awnings are a ways up. It’s unsafe to climb ladders for cleaning jobs as they become wet, soapy and even more slippery than normal.
Also the area just under awnings are starved of sunlight and tend to trap cool air that’s conducive to mold formation, making it a prime candidate for soft washing.
Mix a 12% bleach solution and apply a primary rinse with a high pressure tip on your pressure washer. Because you’re covering so much distance the water pressure will be low enough on impact to prevent any damage to the surface. Wait 10 minutes and rinse with water thoroughly.
6. Moldy Concrete Foundation
If your home has a concrete foundation that’s exposed, you can technically pressure wash it. Concrete is certainly one material that can withstand the high pressure water emission that a pressure washer provides.
But you really want to kill the mold with a 12% bleach to water solution first. Use a wide angle tip to apply that solution. You could use a high pressure tip in this case, but it’s not recommended. Aerosolizing that solution in such close proximity to the surface you’re spraying can result in inhalation of bleach, which is not healthy.
After spraying the bleach solution onto the concrete foundation and waiting 10 minutes, then you can rinse with a high pressure tip.
7. Stucco
Stucco is an aggregate mixture of cement, lime, sand and water that has a thin finish coat. It gives a textured look to the walls of homes. That texture, unfortunately, also accumulates dirt and grime which is why many home owners are tempted to blast it with a pressure washer.
That’s the last thing you want to do.
Instead, try soft washing stucco. First a 12% bleach to water mixture or even a dish soap solution, followed by a thorough rise with your wide angle pressure washer tip. If you don’t have bleach, your dish soap could work. Make a detergent with 1 tablespoon of dish soap per gallon of water.
Troubleshooting
If you’re finding that you have some stubborn mold & dirt that’s not coming out with a simple soft wash, you may need to kick it up a level.
One thing you can do is purchase a surfactant to add your mixture. A surfactant is a chemical that reduces the surface tension of water. It’ll help the bleach and water stick to the surface you’re soft washing just enough to allow them to soak the dirt, grime & mold a bit longer, thus improving the solution’s cleaning power.
Be Aware of Your Plants
Another thing to keep in mind when soft washing is where the runoff is going, especially if you decide to add a surfactant to your solution. The chemicals used in soft washing, particularly bleach, are harmful to plants.
Be sure to thoroughly rinse and water your plants if any solution comes in contact with them. If you use a surfactant, you’ll need to take even more time to rinse your plants as it acts to make your solution a bit more sticky.
Conclusion
Hopefully you’ve learned a bit about the soft washing technique using a pressure washer. It’s essentially using the pressure washers ability to infuse cleaning chemicals into a stream of low pressure water out of the machine.
You also now know of 7 things on your house you should soft wash rather than pressure wash. I hope this article has helped add some like to the delicate parts of your house that require gentle cleaning.
