Pressure Washing vs Old Homes: What You Need to Know

Pressure washing—love it or hate it, it’s here to stay. If you’ve ever stared down at your charming but dirt-caked 1920s bungalow and thought, “A pressure washer can fix that,” you might want to hold up. Sure, blasting away grime can seem like a great idea, but if your house is older than the moon landing, you could be doing more harm than good.

Here’s the lowdown: pressure washing has its uses, but when it comes to historic homes, things get tricky. Let’s break it down.

Pressure Washing is a Wrecking Ball for Old Houses

Imagine using a chainsaw to trim your fingernails—sounds like overkill, right? That’s what pressure washing is to historic homes. The high pressure can do some serious damage to the delicate materials on older houses.

We’re talking about wood siding, brick, or even stucco that’s been around for decades (or centuries). Sure you’ll blast away dirt and grime, but you’ll likely end up blasting away paint, lime mortar, and even chunks of wood or brick. And once that material is gone it’s gone forever, plus you’re setting the stage for rot, mold, and a whole heap of expensive repairs.

Pressure washing an old house is not that much different from sandblasting that same house. It can be just as destructive and cause even more long term issues that lurk beneath the surface.

Fun fact: Pressure washers can expel water at up to 4,000 psi—that’s enough to carve your initials into concrete! So, you can imagine what it’ll do to century-old wood or mortar joints.

Water Damage is No Joke

Old homes are already experts at letting water in, these houses were not built as tightly as modern homes and they have a lot of imperfections (uh, character) that can let water get into places it really shouldn’t be.

Pressure washing just gives water more opportunities to sneak into places it shouldn’t. The result? You’re left with rot, mildew, and mold in all the places you really don’t want to see them (hello, framing and insulation).

For homes with wood siding, pressure washing can drive water into the structure where it’s almost impossible to get it out. You might not see the damage right away, but give it a few seasons, and that water is going to start causing some serious issues like below.

• Wood Rot
• Black Mold
• Peeling Paint
• Mildew
• Wood Damage

Paint Job Suicide

Do you love scraping paint? Didn’t think so. But if you pressure wash your house, you’re basically signing yourself up for more scraping than you ever wanted. High-pressure water can strip paint faster than a belt sander.

If your home has lead-based paint (as many pre-1978 homes do), pressure washing could send lead particles flying, which is not exactly a great addition to the neighborhood air and soil quality.

Add to that the fact that forcing water behind the wood siding results in water logged siding and insulation that in addition to the next issue on the list it will cause future peeling paint. Paint won;t adhere to wood with a high moisture content and pressure washing creates a huge spike in moisture content.

Mold’s Best Friend

You think you’re cleaning, but what if you’re actually feeding the mold? Pressure washing doesn’t just clean—it forces water into every nook and cranny, and mold loves moisture.

Instead of killing off the mold, you could be setting up the perfect breeding ground for it to spread behind the walls, in your attic, or even in your basement. It also forces mold spores from the durface of your siding back into the wall cavities where it’s warm and cozy growing in your sopping wet insulation.

Pressure washing is like handing mold an all-you-can-eat buffet pass. No thanks.

The Smarter (and Safer) Alternatives

So, what’s a dirt-loving, cleanliness-craving homeowner supposed to do? Here are some alternatives to pressure washing that’ll clean your home and keep it intact:

• Soft Washing: It’s like pressure washing’s kinder, gentler cousin. This method uses a lower pressure (typically under 1500 psi) and cleaning solutions to safely remove grime without the destruction.
• Scrubbing by Hand: Yeah, it’s old school. But if you want to preserve your home’s charm, sometimes there’s no substitute for elbow grease. Grab a scrub brush on a extension pole, mild detergent, a ladder, and get scrubbing.
• Low-Pressure Hose & Cleaning Solution: For dirt, grime, and algae that haven’t yet become one with your house, a garden hose and a biodegradable cleaner will often do the trick. Much safer and far less aggressive.

Our Favorite Cleaners

It is possible to get fantastically clean surfaces without using harsh chemicals and ridiculously powerful pressure washers. Check out some of our no-hassle options that anyone can use easily.

• White Vinegar: A timeless classic that never fails to deliver a non-toxic but deadly blow to mold and mildew. Mix it 1:1 with water and spray it on using a pump sprayer then let it sit 15 mins and come back to wash it off.
• D2 Solution: For tough algae and other undesirable plant life on your masonry this stuff is like magic. No dilution needed, you can apply it just like the white vinegar and watch things disappear. For big issues it may require a little scrubbing.
• Dish Soap: If it’s just dirt then the same stuff you clean your dinner plates with will clean your siding or brick. Don’t go overboard to avoid an impromptu foam party.

When You Should Pressure Wash (Carefully)

We get it. Sometimes, pressure washing is unavoidable. Here’s when it might be okay:

1. Concrete Surfaces: Driveways, walkways, and patios are tough enough to withstand the power of a pressure washer.
2. Mildew and Algae in Non-Sensitive Areas: Got a mossy stone wall or some mildew on the driveway? Pressure washing is your friend—just keep it far away from anything delicate.
3. Vinyl Siding: If your historic home has vinyl siding, you’re in luck. Vinyl can usually take a pressure washing as long as the pressure is kept low. On the other hand, if you hate vinyl siding as much as I do, tearing it off may be a better option.

Final Word

Sure, pressure washing can be tempting—quick, easy, and (momentarily) satisfying. But with an old home, it’s a game of Russian roulette. One bad pass and you could be looking at thousands of dollars in repairs. So, before you unleash that high-powered hose on your house, think about the long-term consequences. Your home has stood the test of time; treat it with the respect it deserves.

Pro Tip: Always test in a small, inconspicuous area if you do decide to pressure wash. Better to damage a small patch of siding than an entire wall, right?

Get out there, clean smart, and keep your historic home looking fresh for another 100 years!