7 Things You Should Soft Wash (Not Pressure Wash) On Your House

Soft washing cleans with chemicals and a large volume of water instead of pressure. It’s a popular way to clean the exterior of a home without damaging siding and other parts that don’t hold up well under high water pressure. Below is what you should soft wash versus pressure wash on your home.

Pressure Washing vs. Soft Washing

The difference matters because a lot of people ask this question without finding many good answers. Soft washing means applying a chemical solution to a surface and rinsing it with water, while pressure washing relies on water pressure alone to do most of the cleaning.

Both methods usually use a pressure washer, though.

Soft washing is just a method of pressure washing, minus the pressure.

Some professional outfits use a dedicated “soft washing machine” built for high volume, low pressure water streams. Most homeowners can get the same effect with a regular pressure washer, using the widest-angle tip at the lowest PSI and highest volume setting. Some pressure washer guns also have adjustable PSI built in.

Chemical Soft Washing for Mold, Mildew & Algae

Soft washing works well when killing mold or mildew is part of the job. Most techniques call for a 12% bleach-to-water solution, applied to the surface and left to sit for several minutes before rinsing. That kills mold more effectively, and keeps it from coming back, than water pressure alone.

The Safety Benefit of Soft Washing Hard-to-Reach Areas

Skip the ladder. A high-pressure tip on your pressure washer can soft wash hard-to-reach spots from the ground, so you don’t have to climb up and scrub under a second-story roof overhang. Just be careful not to hit your siding up close with that high-pressure tip. Delicate siding can get damaged by the high-pressure stream from a pressure washer.

7 Things to Soft Wash on Your Home

Here are 7 things you might be wondering whether to pressure wash or soft wash:

1. Solar Panels

Solar panels are made of delicate materials that can easily get damaged under a pressure washer’s PSI, and they’re often up on the roof where a direct spray is hard to control anyway. Soft washing is the better call here.

Harsh detergents like bleach can damage solar panels, though, so mix a window-washing solution instead: window washer fluid and water at a 1:1 ratio.

Wait 10 minutes, then rinse thoroughly with water. Skip leaving a soapy residue behind, since it just attracts more dust and pollen.

2. Hardie Board

Hardie board is a durable siding made from cement, sand, and cellulose fibers, but repeated pressure washing can wear it down over time. Soft wash it instead.

First figure out what you’re removing. For plain dirt, soft wash with a soapy water mixture in your pressure washer’s detergent tank, about a tablespoon of dish soap per gallon of water.

For mold or algae, mix 12% bleach with water instead. Spray it on with a wide-angle tip, wait 10 minutes, then rinse with plain water using the same tip.

3. Windows & Window Frames

Windows and their frames are some of the most delicate parts of a home. The sealant holding a window to its frame can strip away under the force of a pressure washer, and that same sealant tends to attract mold and mildew.

Soft wash windows with a 12% bleach-to-water solution for the first rinse. Wait 10 minutes, then rinse with a wide-angle, low-pressure tip.

4. Metal or Wood Roofs

Skip pressure washing metal or wood roofing altogether. Wood shingles can come loose under a fairly small amount of force, and a powerful pressure washer can damage them outright. Metal roofs get dangerously slippery when wet, so it’s safer to clean from the ground when you can.

Soft wash your metal or wood roof with a 12% bleach-to-water solution instead. Use a narrow-angle tip if you need one to reach the roof, but be careful not to spray anywhere else on your home with it. Wait 10 minutes, then rinse thoroughly with plain water.

5. Hard-to-Reach Awnings

Climbing a ladder gets riskier once it’s wet and soapy, and multi-story awnings are exactly the kind of hard-to-reach spot where that risk shows up.

The shaded, cool air under an awning is also a good breeding ground for mold, which makes it a strong candidate for soft washing.

Mix a 12% bleach solution and apply the first rinse with a high-pressure tip. Since you’re covering more distance, the water pressure will have dropped enough by the time it hits the surface to avoid damage. Wait 10 minutes, then rinse thoroughly with water.

6. Moldy Concrete Foundation

An exposed concrete foundation can technically handle a straight pressure wash, since concrete holds up fine under high water pressure.

But kill the mold first with a 12% bleach-to-water solution, applied with a wide-angle tip. A high-pressure tip works too, but it’s not recommended: spraying that solution at close range can aerosolize it, and breathing in bleach isn’t good for you.

After the bleach solution sits for 10 minutes, rinse with a high-pressure tip.

7. Stucco

Stucco is a textured mix of cement, lime, sand, and water with a thin finish coat, and that texture collects dirt and grime fast, tempting a lot of homeowners to blast it with a pressure washer.

Don’t. Soft wash it instead: apply a 12% bleach-to-water mixture, or a dish soap solution (1 tablespoon of dish soap per gallon of water) if you don’t have bleach on hand, then rinse thoroughly with a wide-angle tip.

Troubleshooting

Stubborn mold or dirt that won’t budge with a simple soft wash usually means it’s time to add a surfactant to your mixture. A surfactant cuts the surface tension of water, helping the bleach solution cling to the surface long enough to soak into the dirt, grime, and mold instead of running off.

Be Aware of Your Plants

Keep an eye on where your runoff is headed, especially if you’re using a surfactant. Bleach and other soft-washing chemicals are harmful to plants, so rinse and water any plants that end up in the splash zone. A surfactant makes the solution stickier, so plan on rinsing plants a bit longer if you’re using one.

Soft washing uses a pressure washer’s ability to push cleaning chemicals through a low-pressure stream of water, instead of relying on force alone. Now you know 7 things on your house that call for that gentler touch instead of a straight pressure wash.