10 Things You Should NEVER Pressure Wash

1. Asphalt Roof Shingles

As mentioned in our roofing guides, high pressure removes the granular coating that protects shingles from UV rays, effectively ruining the roof. It can also dislodge shingles, creating leaks. Never use a pressure washer on a roof; soft washing is the only safe method.

Why it fails: The granules are what makes the shingle waterproof. Blasting them away leaves your roof vulnerable to leaks and rot.

2. Electrical Panels and Meters

This should be obvious, but water and high voltage don't mix. Even exterior grade panels are not designed to withstand a 3000 PSI blast. Stay at least 3-4 feet away and use only light mist if absolutely necessary. Always turn off power if possible.

The Risk: Short circuits, electrocution, or blowing the main fuse.

3. Old Standard Brick & Mortar

While new brick can handle moderate pressure, historic or older brick homes (pre-1980s) have softer mortar joints. A high-pressure blast can literally blow the mortar out from between the bricks, compromising the structural integrity of the wall.

Warning: Once the mortar is gone, the bricks become loose and can fall out.

4. Windows and Glass Doors

Glass surfaces, particularly older or single-pane windows, can crack or shatter when exposed to high-pressure water streams. Furthermore, pressure washing can damage the seals around windows, leading to drafts and water leaks.

Tip: Use a garden hose and sponge instead for windows.

5. Your Car or Truck

You might be tempted to pull out the pressure washer to clean your car, but you could end up damaging your paint job or denting soft panels. The pressure can also force water into door seals and cause rust. It's safer to take your car to the car wash.

Detail: Car paint is thinner than you think. A pressure washer can easily strip wax and polish.

6. Live Plants & Landscaping

Never point a pressure washer at your prized hydrangeas or bushes. The force can strip bark, damage roots, and destroy the plant. Always cover delicate plants or use a gentler method like a garden hose.

Protection: Cover plants with plastic sheeting before starting any pressure washing project.

7. Lead Paint

If your home was built before 1978, it likely has lead-based paint. Pressure washing lead paint is incredibly dangerous, as it creates toxic dust and sludge. It requires professional abatement.

Health Hazard: Inhaling lead dust can cause serious neurological damage.

8. Asbestos Siding

Homes built between 1920 and 1980 may have asbestos in the siding. Pressure washing asbestos siding releases dangerous fibers into the air. This requires special handling and removal by a certified professional.

Legal: Disturbing asbestos incorrectly is illegal in many areas.

9. Wicker and Rattan Furniture

Outdoor wicker and rattan are often made from natural fibers or resin. High pressure can break the fibers, unravel the weave, and ruin the furniture. Use a gentle sponge and soap instead.

Care: Clean wicker with a mild soap and water solution.

10. Air Conditioning Units

Don't spray your AC unit! The fins are delicate and can be bent or punctured by high pressure, reducing efficiency and causing leaks. Keep the unit clean with a soft brush or gentle hose rinse.

Maintenance: Bent fins reduce airflow and make your AC work harder, raising your energy bills.

When in Doubt, Call a Pro

If you aren't sure whether a surface can handle the pressure, don't risk it. Calling a professional ensures the job is done safely and correctly, saving you money on costly repairs in the long run.

Also, avoid spraying painted wood siding or trim with high pressure, as the force can blast the paint right off the wood.