What PSI Do You Need to Pressure Wash a House vs. Driveway vs. Roof?
Published July 5, 2026 · Krystal Klean Exterior
PSI is not a bigger-is-better number. Here is the pressure each surface actually needs, from roofs at garden-hose pressure to concrete at 3,000+ PSI, and why too much causes expensive damage.
"What PSI do I need?" is the most common question we get from homeowners shopping for a pressure washer, and the honest answer surprises people: for most of your house, you want less pressure, not more. PSI (pounds per square inch) measures force, and force is exactly what cracks vinyl, strips paint, gouges wood, and destroys roof shingles. Here is the pressure each surface on a Florida home actually needs, and why the pros reach for chemistry before they reach for the trigger.
PSI by surface: the quick chart
| Surface | Recommended pressure | Method |
|---|---|---|
| Roof (shingle, tile, metal) | Under 100 PSI (garden-hose level) | Soft wash only |
| Vinyl, stucco & painted siding | Under 500 PSI | Soft wash |
| Window screens & pool cage | Under 300 PSI | Soft wash / gentle rinse |
| Wood deck or fence | 500 – 1,200 PSI | Low pressure + cleaner |
| Brick pavers | 1,000 – 2,000 PSI | Controlled, then re-sand |
| Concrete (driveway, sidewalk, pool deck) | 3,000 – 4,000 PSI | Surface cleaner |
Roofs: the lowest pressure of anything on your home
This is the one that costs homeowners the most money when they get it wrong. A roof should never be pressure washed. High pressure blasts the protective granules off asphalt shingles, cracks tile, drives water under the courses, and voids most manufacturer warranties. The black streaks on Tampa Bay roofs are a living algae, Gloeocapsa magma, and force does not kill it, chemistry does. The correct method is a soft wash: an algaecide applied at essentially garden-hose pressure (under 100 PSI) that kills the organism at the root and rinses clean. More on that in our guide to the black streaks on your Florida roof.
Siding: under 500 PSI, and let the soap do the work
Vinyl, Hardie board, stucco, and painted wood all clean at under 500 PSI. That is a soft wash, low pressure combined with a biodegradable detergent that kills mold and mildew instead of blasting it off. High pressure on siding is a classic DIY mistake: it cracks vinyl, chews up the chalky layer on stucco, strips paint, and, worst of all, drives water behind the siding into the wall cavity where it grows mold you cannot see. If your "house washing" plan involves a high-pressure wand near the walls, it is the wrong plan, see how house washing should actually be done.
Wood decks and fences: 500 to 1,200 PSI, with a light touch
Wood is soft, and the grain tears easily. Softwoods like pine and cedar clean best at the low end, around 500 to 800 PSI, while denser hardwoods can take up to about 1,200. Even then, technique matters more than the number: keep the tip moving, hold it back from the surface, and follow the grain. Too much pressure raises "furring" (fuzzy torn fibers) and leaves permanent wand marks. A cleaner plus low pressure beats brute force every time.
Pavers: 1,000 to 2,000 PSI, then re-sand
Brick and concrete pavers can handle more pressure than wood, but there is a catch that has nothing to do with the paver surface: pressure blows the sand out of the joints. Clean pavers too aggressively and you have a nice-looking driveway that is now structurally loose, ready to shift, sink, and grow weeds. That is why a proper paver cleaning is controlled and always followed by fresh polymeric joint sand. Never let a pressure washer treat your pavers like a concrete slab.
Concrete: this is where high pressure belongs
Flat concrete, driveways, sidewalks, patios, and pool decks, is the one place you actually want 3,000 to 4,000 PSI. But even here, pros do not use a straight wand. They use a surface cleaner, a spinning-bar attachment that spreads the pressure evenly and gives you a clean, stripe-free finish. A bare wand at 4,000 PSI leaves the "zebra marks" you see on DIY driveways and can etch permanent lines into the concrete. See our pressure washing service for how flat concrete gets done right, and our driveway cost guide for pricing.
PSI is only half the story: GPM matters more than you think
Homeowners fixate on PSI, but professionals care just as much about GPM, gallons per minute. PSI is the force that breaks the bond between dirt and the surface; GPM is the water volume that carries the dirt away. A machine with high PSI but low GPM cleans slowly and tempts you to get too close and too aggressive. This is a big reason a professional job on a large driveway is faster and cleaner than a consumer machine: commercial units move far more water. It is also why "just buy the highest-PSI machine at the store" is the wrong instinct.
The rule that keeps you out of trouble
Start with the lowest pressure that will do the job, and let detergents do the work whenever the surface is delicate. Roofs and siding get chemistry and almost no pressure. Wood gets a light touch. Pavers get controlled cleaning and new sand. Only bare concrete gets full pressure, and even then through a surface cleaner. If you match the method to the material, you clean everything without damaging anything.
Frequently asked questions
What PSI do you need to pressure wash a house?
Siding should be cleaned at under 500 PSI using a soft wash, low pressure plus a cleaning detergent. High pressure cracks vinyl, strips paint, damages stucco, and can force water behind the siding, so more pressure is not better on a house exterior.
What PSI do you need to clean a concrete driveway?
Concrete driveways clean best at 3,000 to 4,000 PSI, delivered through a surface cleaner attachment rather than a bare wand so the result is even and stripe-free.
Can you pressure wash a roof?
No. Roofs should never be pressure washed. High pressure strips shingle granules, cracks tile, and voids warranties. Roofs are cleaned with a soft wash at under 100 PSI, using an algaecide that kills the algae at the root.
What PSI is safe for a wood deck?
Most wood decks and fences clean safely at 500 to 1,200 PSI, with softwoods like pine and cedar at the lower end. Keep the tip moving and follow the grain to avoid tearing the wood fibers.
Is higher PSI always better for pressure washing?
No. PSI is force, and too much force damages most home surfaces. The right approach is the lowest pressure that cleans the surface, plus enough water volume (GPM) to carry the dirt away. Only bare concrete calls for high pressure.
Related reading: soft wash vs. pressure wash, which method your Florida home needs, and Tampa Bay pressure washing cost. Not sure what your surfaces can take? Text photos to 727-579-7825 and we will tell you the right method and pressure for each one.