Your deck,
washed.

For soft wood decks (PT, cedar): 1500-2700 PSI maximum. Higher PSI splinters the surface and ages wood faster. Most home decks: electric 2000 PSI (gentlest) or gas 2700 PSI (fastest safe option). Use a 25° fan nozzle and maintain 12-18″ standoff from the wood. Gas 3500+ PSI is only safe with rotary surface cleaner attachment — not direct spray on bare wood. NEVER use 4000+ PSI on cedar or pine; it gouges the fibers.

Only if your deck has light dust and no mildew. Water alone removes ~30% of typical deck grime. For real cleaning, you need either: (1) oxygen-based cleaner (Behr Premium, Olympic — plant-safe, $22/gal), (2) bleach-based cleaner (Wet & Forget — aggressive mildew, kills plants, $18/gal), or (3) full deck stripper if removing failed stain ($32/gal). Apply cleaner → wait 10 min → pressure rinse. Skipping the chemical step is the most common DIY mistake.

Rent if: deck < 800 sqft, you have an outlet/garden hose handy, you want to do it on your schedule. Rental $45-125/day at Home Depot/Lowes — Sunday morning return drops cost since you only pay for Saturday. Hire if: deck > 800 sqft, severe mildew/stripping needed, you don't want to manage chemicals/disposal. Contractor average $0.35-0.65/sqft turnkey. Get 3 quotes for jobs > $400. Many contractors bundle deck + driveway + siding for 15-30% multi-service discount.

400 sqft deck with gas 2700 PSI, oxygen cleaner, 1 cleaner cycle, moderate weathering: 1.5-2.5 hrs total (wash + cleaner application + rinse). Heavy mildew with 2 cycles: 2.5-4 hrs. Stain stripping: 3-5 hrs (slow + careful). DIY adds 30-50% time for setup/cleanup/learning. Contractor crew: 0.75-1.5 hrs same scope (commercial equipment + practiced workflow). Plan a half-day for DIY work + 24 hr drying time before any stain/sealer application.

Recommended yes — wood brightener (oxalic acid) neutralizes any bleach residue, restores wood color (clean pine/cedar looks yellow-tan), and prepares the surface for stain. About $26/gal at 320 sqft/gal — ~$30-50 for typical deck. Apply with garden sprayer after pressure washing dries (24-48 hr). Rinse with clean water. Skip brightener only if you're not staining (just cleaning maintenance) or using a stain that includes brightener (some Penofin products).

Yes, two main risks: (1) wood splintering — > 2000 PSI on soft wood without proper standoff lifts fibers, (2) board displacement — water blasting between boards can lift fasteners + cup boards. Mitigations: use 25° nozzle (NOT 0° pencil tip), maintain 12-18″ standoff, spray WITH the grain (lengthwise on boards), avoid pressure-blasting board ends + screw heads. Older PT decks with rot may have weakened spots where pressure tears chunks loose — inspect after washing.

Most jurisdictions: oxygen-cleaner runoff is fine to drain to landscaping (alkaline). Bleach runoff (sodium hypochlorite) is regulated in some MS4 stormwater jurisdictions — must be captured and disposed of as hazmat ($25 disposal fee). Stripper runoff is always regulated — must be neutralized and captured. Check your local MS4 (Municipal Separate Storm Sewer System) rules. Most homeowners use oxygen-only and direct runoff to lawn or mulched beds (where it acts as fertilizer).

Yes — almost always. Stain needs to penetrate clean wood to bond properly. Power washing removes: dirt, mildew, mold, pollen, weathered fibers, residual UV-damaged surface, and any failed previous coating. Without this prep, new stain peels within 12-24 mo. Even brand-new PT decks benefit from a light pressure wash to remove mill glaze + treatment-chemical residues. The only skip-power-wash scenario: 6-month touch-up recoat of same stain in same year.

1 cycle for lightly-to-moderately dirty decks. 2 cycles for heavily soiled or visible mildew. 3 cycles for stain stripping or restoration jobs (often paired with stripper chemical). Each cycle: apply cleaner with garden sprayer → let dwell 10-15 min (don't let it dry) → pressure rinse → inspect → repeat if needed. More cycles = more cleaner gallons + more time + more cost. The condition multiplier in the calculator already adjusts concentration; cycle count multiplies that further.