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What Shouldn’t You Power Wash?
Quick answer: Never power wash asphalt shingle roofs, windows, electrical panels, gutters, old brick mortar, wicker or teak furniture, or pool liners, since high-pressure water strips protective coatings and can cause structural or electrical damage. If you’re washing a house exterior, know which materials on it are safe at full pressure and which need a soft-wash or hand-cleaning approach instead.
The Biggest Mistake: Power Washing a Roof
Nothing sparks more disagreement among DIYers than roof power wash jobs, and the debate plays out in real time on forums. On a TractorByNet thread about cleaning mildew and stains from asphalt roof shingles, one member described successfully washing stained shingles using a 2,700 PSI machine, but only with the nozzle held well back from the surface and a dedicated house-wash soap doing most of the actual cleaning work rather than raw pressure.
But further down the same thread, another member pushed back hard, saying they couldn’t imagine using a pressure washer at any rated PSI on their roof, and pointed out that insurance companies increasingly mandate full roof replacement once shingles visibly lose their protective granules — the exact damage high pressure causes.
“I can’t imagine using a pressure washer of any rated pressure to clean my roof, since insurance companies are mandating roof replacement when the roof appears worn, which is basically the granules that have washed away.”
That take lines up with industry guidance: the Asphalt Roofing Manufacturers Association recommends a low-pressure bleach-and-water solution instead of mechanical pressure for cleaning algae and moss off asphalt shingles, and explicitly warns that pressure washing a roof above about 100 PSI can cause damage.
Using a pressure washer, or any other gas-powered device, to clean a roof at more than 100 PSI can damage the roof, and the Asphalt Roofing Manufacturers Association recommends a bleach cleaning solution without pressure instead
The safest approach, and the one most professionals now use, is called soft washing — low-pressure water combined with a cleaning solution that does the actual work, rather than force.
Soft washing uses low-pressure water, typically with a sodium hypochlorite-based solution, to remove mildew, bacteria, and algae from roofs, and is considered much safer than high-pressure cleaning.
For a deeper breakdown of when pressure washing a roof is appropriate versus when to call in a pro, see our guides on is roof pressure washing a good idea and roof cleaning vs. pressure washing.
What Else You Should Never Power Wash
Beyond roofs, several other common targets consistently show up on “never pressure wash this” lists from consumer and home-safety sources:
Windows. The concentrated stream can crack panes, tear screens, and force water past worn caulking into the wall cavity — even on windows that look structurally solid. Pressure washers concentrate water hard enough to crack panes, rip screens, and force water through worn caulk, even on windows that look solid.
Electrical panels, meters, and light fixtures. Mixing a high-pressure water stream with live electrical equipment is a straightforward way to cause a short, a shock, or worse.
Gutters. It’s tempting to blast leaves out of gutters, but the pressure can dent the metal, loosen fasteners, and in some cases pull entire gutter sections away from the fascia.
Old brick and mortar. Pressure washing can strip mortar that’s already weathered, undoing decades of structural stability in a single pass. We cover safe techniques for newer brick in our brick and mortar pressure washing guide.
Wicker, teak, and other natural-fiber furniture. Sturdy plastic, metal, or resin patio furniture generally handles pressure washing fine, but natural woven materials fray and splinter under the same force. See our full rundown in outdoor furniture cleaning mistakes to avoid.
Pool liners. Vinyl and fiberglass liners puncture easily, and plaster pool shells can crack under direct high-pressure contact.
Air conditioner fins and units. The thin metal fins bend under pressure, which reduces airflow and can increase the unit’s energy use going forward.
How to Power Wash a House the Right Way
If your actual goal is cleaning the whole exterior, how to power wash a house safely comes down to matching pressure to material, not blasting everything at max PSI. Vinyl and fiber-cement siding generally tolerate moderate pressure; painted wood, stucco, and anything with visible wear should get a lower-pressure soft wash instead.
Our complete walkthrough on pressure washing a house safely or hiring it out covers the surface-by-surface breakdown, and our general guide on what shouldn’t you pressure wash goes deeper into technique for each material.
If you’re uneasy tackling the whole job yourself — especially the roof, gutters, or anything near electrical lines — it’s worth getting quotes from power washing services rather than risking expensive repairs.
Our guide to finding reliable pressure washing services near you walks through what to look for. We’ve also covered the injury side of DIY power washing in our breakdown of the cons of pressure washing, which is worth a read before you start any high-risk surface yourself.
The Right Equipment for Safe House Washing
For most siding and hard surfaces, a mid-range electric unit with adjustable nozzles gives you enough control to switch between higher pressure for concrete and a wide, low-pressure fan for siding.
Sun Joe SPX3000 (adjustable nozzles, good for mixed-surface house washing) →
Pressure Washer Soft Wash / Chemical Injector Kit →
If solar panels are part of your house wash plan, resist the urge to spray them directly — see our guide on whether you can pressure wash solar panels before you start.
Bottom Line
The rule of thumb: if a surface is fragile, aging, electrical, or load-bearing in a subtle way (like roof granules or old mortar), skip the pressure washer entirely or switch to a soft-wash approach. Reserve full pressure for driveways, sealed concrete, and durable siding, and when in doubt — especially on the roof — the forum consensus and the manufacturers agree: less pressure, more chemistry.