Pressure washer PSI chart by surface
Every surface has one pressure that cleans it and one that ruins it, and the gap between them is smaller than most people believe. This chart is the site’s single source for that number: eighteen surfaces, the working pressure band, the tip, and what the chemistry has to do that the pressure cannot. For what each colour of tip does, see the pressure washer nozzle chart.
Safe pressure by surface
| Surface | Working PSI | Nozzle | Detergent |
|---|---|---|---|
| Poured concrete drivewayFlatwork | 3000-3500 | 25 deg Green / 20 in surface cleaner | Degreaser pre-treat, dilute SH post-treat |
| Concrete sidewalk and stepsFlatwork | 2500-3200 | 25 deg Green | SH post-treat |
| Stamped or decorative concreteFlatworkSealed surface — pressure hazes and strips the colour coat. | 1200-1500 | 40 deg White | Neutral cleaner |
| Concrete paversFlatworkEmpties joint sand; plan to re-sand. | 1500-2500 | 25 deg Green | Efflorescence remover if blooming |
| Asphalt drivewayFlatworkPressure lifts the binder and exposes aggregate. | 1200-1500 | 40 deg White | Neutral cleaner |
| Garage floor with oilFlatwork | 3000-3500 | 15 deg Yellow then green | Alkaline degreaser, long dwell |
| Vinyl sidingVerticalPressure drives water behind the courses. | 100-500 (soft wash) | ~65 deg Black soap, white rinse | 0.5-1.5% SH + surfactant |
| Fibre-cement sidingVertical | 100-500 (soft wash) | ~65 deg Black soap, white rinse | 0.5-1.5% SH + surfactant |
| Painted wood sidingVerticalTest for chalking first — chalked paint is a paint job. | 100-400 (soft wash) | ~65 deg Black soap, white rinse | Mild detergent |
| Stucco and EIFSVerticalEIFS is foam behind a skin. Pressure punches through. | 100-500 (soft wash) | ~65 deg Black soap, white rinse | Low-strength SH |
| Brick and mortarVerticalBIA: over 800 PSI is not appropriate for brick. Soft or historic brick spalls; test patch, always. | Up to 400 (BIA) | 25 deg Green | Masonry cleaner, pre-wet |
| Natural stoneVerticalAcid etches limestone and marble permanently. | 800-1500 | 40 deg White | pH-neutral stone cleaner |
| Cedar and softwood deckingWoodFurs at pressure. Work with the grain, tip well back. | 500-1200 | 40 deg White | Sodium percarbonate, neutralising rinse |
| Pressure-treated deckWood | 600-1200 | 40 deg White | Percarbonate cleaner |
| Composite deckingWoodExceeding the maker's figure voids the warranty and hazes the boards. | Manufacturer max, often <=1500 | 40 deg White | Approved cleaner only |
| Wood fenceWood | 500-1200 | 40 deg White | Percarbonate cleaner |
| Asphalt shingle roofRoof & gutterARMA: do not use a power washer, brush or broom on shingles. | Soft wash only | ~65 deg Low-pressure soft-wash tip | ~3% SH, 15-20 min dwell |
| Aluminium gutter faceRoof & gutterOxidation stripes are chemical, not pressure. Pressure dents the trough. | Under 500 | 40 deg White | Gutter-brightening surfactant, brushed |
Showing 18 of 18 surfaces. Every colour dot is named in text beside it — the colour is data here, not decoration.
Start low, every surface
- 1. Bottom
- Set the machine or the stand-off to the bottom of the band.
- 2. Back
- Start well back and close in slowly; distance is a pressure control.
- 3. Patch
- Test where nobody looks, then let it dry before you judge it.
- 4. Stop
- Lines, fuzz or a colour change means you are past the band.
- 5. Chem
- Still dirty at the top of the band? Add dwell time, not pressure.
How to read a band
Start at the bottom of the band and work up only if the surface is not coming clean. Most damage happens because someone started at the top. Distance matters as much as the dial: the same 3,000 PSI at six inches and at eighteen inches are two different tools, which is why the PSI guide treats stand-off as the third setting on the machine.
- Find the surface and filter the chart to its group.
- Fit the tip in the nozzle column and set the machine, or the stand-off, to the bottom of the band.
- Test a patch somewhere nobody looks: behind a downpipe, under a step, the corner of the slab. Let it dry before you judge it, because wet concrete and wet siding hide marks.
- Step up only if the patch is still dirty, and stop the moment you see lines, fuzz or a change in colour.
Surface damage risk
Why each group sits where it does
Flatwork
Poured concrete is the one surface that takes the top of the range: 3,000–3,500 PSI through a surface cleaner sized to your flow, with a degreaser before and a dilute hypochlorite rinse after. Everything else on this list that looks like concrete is softer than it looks. Stamped concrete carries its colour in a thin coat, asphalt is held together by a binder that pressure lifts, and pavers lose their joint sand, so all three sit lower and start lower.
Vertical
Siding, stucco and painted wood are a soft-wash job, not a pressure job. The band printed is the pump pressure of a soft-wash setup, 100–500 PSI, and the cleaning is done by the mix in the soft wash mix calculator. Brick is the exception that still takes a wand, and the Brick Industry Association caps it at 400 PSI at the tip, with anything over 800 PSI ruled out.
Wood
Wood fails by furring: the soft spring growth between the rings tears out and leaves a fuzzy, grey surface that takes stain badly. Keep softwood decks and fences at 500–1,200 PSI with the white 40-degree tip, work along the grain, and let a percarbonate cleaner do the work. Composite boards follow the maker’s own maximum, never the deck’s apparent toughness.
Roof & gutter
Asphalt shingles get no pressure at all. The shingle makers’ association says not to use a power washer, brush or broom on them, so the roof row is a mix, a 15–20 minute dwell and a gentle rinse. Gutter faces stay under 500 PSI because the stripes on them are bonded film, which a brushed brightener lifts and a jet only dents the trough trying to shift.
The three surfaces people get wrong
- Stamped concrete. It looks like concrete and behaves like a coating. The colour lives in a thin surface layer that pressure hazes and strips.
- EIFS. Synthetic stucco is foam behind a thin skin. Enough pressure to clean ordinary stucco will punch a hole you cannot see until it rains.
- Brick. It feels like the toughest thing on the house. The industry’s own technical note says 400 PSI at the tip, and the brick cleaning guide explains why.