The Pressure Washing PSI Chart
Safe pressure, nozzle, and method for every exterior surface. Compiled by the crew at Up North Pressure Washing in Duluth, MN, from manufacturer specifications and a few thousand jobs in one of the harshest exterior climates in America. Free to reference or share — a link back to this page is appreciated.
Safe PSI by Surface
| Surface | Safe PSI | Nozzle / Method | Why it matters |
|---|---|---|---|
| Asphalt shingle roof | Never pressure wash | Soft wash only (under 100 PSI, SH-based solution) | Pressure strips granules and voids most shingle warranties. GAF, Owens Corning, and ARMA all specify low-pressure cleaning only. |
| Vinyl siding | Soft wash preferred; max 1,300–1,600 | 40° white tip, downward angle | High pressure forces water behind panels, causing hidden mold and warping. Never spray upward into laps. |
| LP SmartSide / engineered wood | Soft wash only | Low-pressure rinse | LP's own maintenance guide warns pressure washing can void the substrate warranty. |
| Stucco / EIFS / Dryvit | Soft wash only (under 500) | Wide fan, kept moving | Pressure pits the finish coat and opens hairline cracks that freeze-thaw cycles then destroy. |
| Wood deck (cedar, pine) | 500–800 | 40° tip, with the grain, 12″+ standoff | Anything stronger furs the grain and gouges soft spring wood. Cleaners do the work, not pressure. |
| Composite deck (Trex, etc.) | Under 1,500 (check brand) | 40° fan tip, 8″+ standoff | Trex allows up to 1,500 PSI; some brands void warranties over 1,000. Verify before you spray. |
| Brick & mortar | 500–1,000 | Wide fan, test a hidden spot | Older lime mortar erodes fast. Pre-1930 brick should usually not be pressure washed at all. |
| Natural stone | 500–1,500 (varies) | Wide fan | Sandstone and limestone are far softer than granite. When in doubt, soft wash. |
| Concrete driveway / sidewalk | 2,500–3,500 | Surface cleaner + hot water for oil/salt | Concrete is the one surface that genuinely needs pressure. Hot water is what releases oil and winter salt film. |
| Pavers | 1,500–2,500 | Surface cleaner, re-sand joints after | Direct high-pressure jets blow out joint sand and shift pavers. |
| Asphalt driveway | Under 1,500 | Wide fan, cool water | Hot water and high pressure both soften and scar asphalt binder. |
| Windows & screens | Never pressure wash | Pure-water pole or hand wash | Pressure breaks seals on double-pane units — a fogged window is a replaced window. |
| Gutters (exterior) | Soft wash | Brush + oxidation-safe cleaner for tiger striping | Pressure won't remove electrostatically bonded striping; it just removes paint. |
| Painted wood siding | 500–1,200 | 40° tip, test first | Pre-1978 homes may have lead paint — chips must not be blasted into soil. Soft wash instead. |
Northland Seasonal Exterior Cleaning Calendar (MN & WI)
Lake Superior weather is its own animal: 80+ freeze-thaw cycles a year, road salt from October to April, heavy June pollen, and lake-effect moisture that feeds algae on north-facing walls all summer.
| Season | What to clean & why |
|---|---|
| April–May | Concrete and garage floors — strip winter salt film before it accelerates spalling. Inspect siding for freeze-thaw cracks and winter mold growth. |
| June | House wash after the pollen drop. Pollen is food for algae; washing it off now prevents the green film by August. |
| July–August | Roof soft washing and deck restoration — surfaces dry fast and treatments cure properly. Best window for staining. |
| September–October | Gutter cleaning after leaf drop, final window cleaning, and a siding rinse so organic matter doesn't sit on the house under snow for five months. |
| November–March | Exterior washing season is over — water freezes on contact. Book spring slots early; the post-thaw rush fills fast. |
Use This Chart
Writers, realtors, hardware stores, and HOA boards: you're welcome to cite or reprint this chart with a link to upnorthpressurewashing.com/pressure-washing-psi-chart. Questions about a surface not listed? Call us at 218-576-8610 — we'll give you a straight answer even if it's a DIY job.
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