Deck Pressure Wash & Restore
The deck off the back of a Seattle craftsman after eight months of wet shade-moisture, leaf tannin stains where the maple drops on the boards every October, the moss bloom on the north side that the homeowner has been kicking off with the toe of a boot for two years, the leaf-debris-and-algae layer that traps moisture against the wood and accelerates surface rot. Deck pressure wash and restore is the trade for resetting the surface — deck-cleaner scrub with sodium percarbonate on wood or a manufacturer-approved composite cleaner, low-to-medium PSI rinse on cedar and pressure-treated tuned to the board condition, much-lower PSI on tropical hardwood and composite to avoid raising the grain or voiding the warranty, optional oxalic brightener neutralize to balance the wood pH and bring back the natural tone, full board screwdown of every popped fastener, and a same-day dated photo report. From $600 for a small wash-only visit to $1,800 for a larger deck with brightener and full screwdown. The wash scope does not include a stain coat — staining and sealing is a separate scope scheduled to a 48-hour rain-free dry window. Homeowners book the wash to prep for a DIY stain, to reset a deck that is not ready for a stain coat year, or to lift moss and leaf grime in advance of summer barbecue season.
Service
What Does Deck Pressure Wash & Restore Include?
Deck pressure wash and restore is a one-visit scope for resetting a deck surface. We scrub with a deck-cleaner sized to the material (sodium percarbonate on wood, manufacturer-approved cleaner on composite), rinse at the right PSI for the board condition (low-to-medium on cedar and pressure-treated, much lower on tropical hardwood and composite), optionally neutralize the wash with an oxalic-acid brightener, walk the boards with screwdown of every popped fastener, check the end-grain at every cut end, and deliver a same-day dated photo report. The scope is wash-and-restore — no stain coat. Stain and seal is a separate scope that requires a 48-hour rain-free dry window and a multi-day cure timeline; we will book the stain visit separately when the homeowner wants it.
Deck Cleaner Scrub Sized to the Material
Cedar, pressure-treated, and tropical hardwood decks get a sodium percarbonate deck cleaner (Olympic Premium Deck Wash, Cabot Problem-Solver Deck Wash, Defy Deck Cleaner, or equivalent). The cleaner is brushed or sprayed on, allowed a 10-to-15-minute dwell time on the surface, scrubbed with a deck brush on stubborn spots, and rinsed with the pressure wand. Composite decks get a manufacturer-approved cleaner — never sodium percarbonate at full strength, never an acid-based cleaner that would etch the composite surface — followed by a low-PSI rinse.
Low-to-Medium PSI on Cedar and Pressure-Treated
Cedar and pressure-treated decks get a low-to-medium PSI rinse with a 25-to-40-degree fan tip held at 8 to 12 inches above the surface. Too high a PSI raises the wood grain, leaves fuzzy fibers standing up that the next stain coat sheets right off, and on cedar can score the soft wood between the grain. The tech adjusts on the spot based on board condition — a fresh-from-the-mill cedar deck gets less pressure than an eight-year-old weathered one. Aged decks may also benefit from a percarbonate dwell-and-soak approach with minimal rinse pressure.
Much-Lower PSI on Tropical Hardwood and Composite
Tropical hardwood (ipe, cumaru, garapa, mahogany) gets a much lower PSI with a wider fan tip (40-to-65-degree) because the dense grain raises quickly under pressure and the next stain coat sheets off. Composite (Trex, TimberTech, Fiberon, Azek) gets the manufacturer-rated low pressure — typically 1,500 PSI fan tip at 12 inches, sometimes lower depending on the brand and the board age. Composite warranties void above the manufacturer-rated pressure; we always check the brand before setting the wand.
Optional Oxalic Brightener Neutralize
After the deck cleaner wash, the wood is alkaline and the surface gray has been lifted. An oxalic-acid-based brightener (Cabot Problem-Solver Brightener, Defy Wood Brightener, or equivalent) neutralizes the wash, balances the wood pH back toward neutral, and brings back the natural wood tone on cedar and pressure-treated. The brightener step adds 30 to 60 minutes to the visit and is recommended on decks older than five years or on any deck that will be re-stained inside six months of the wash. Brightener is optional and quoted as an add-on so the homeowner can decide.
Full Board Walk with Screwdown and Fastener Replace
The tech walks the whole deck on hands and knees after the rinse and screwdrives every popped screw back into the joist — the most common cause of a board working loose on a PNW deck is freeze-thaw cycling backing screws out a half-turn each winter. Corroded fasteners (rusty galvanized heads, broken screw heads) get pulled and replaced with stainless or coated equivalents from truck stock. Hidden-fastener systems get the matched plug. The screwdown is included in the prep-and-restore package; large-volume fastener replacement (more than 25 stainless swaps) is itemized.
End-Grain Rot Check with Borate Treatment
Every cut end on the deck — board ends at the perimeter, stair tread ends, picture-frame mitre joints, post tops — gets a visual and awl-probe check for soft punky wood. Small areas of end-grain rot get treated with a borate wood preservative brushed on the affected end-grain. The treatment penetrates 3/8 to 1/2 inch into the end-grain, blocks fungal growth, and adds five to ten years of life. Larger areas of rot route to the deck board replacement scope; the rot finding goes on the photo report with a recommended follow-up.
Same-Day Dated Photo Report
Before-and-after photos of the deck, the fastener count (how many popped, how many replaced), any end-grain treatments performed, and any flagged items for follow-up (a soft board, a rusting hanger visible from above, a baluster missing). The report goes to the homeowner the same day so the wash visit is documented and any follow-up scope is on record.
How Deck Pressure Wash & Restore Works
Six sequential steps from the on-arrival inspection through the deck-cleaner scrub, rinse, brightener, screwdown, and the same-day photo report — the sequence we follow on every deck pressure wash visit.
On-Arrival Inspection and Material Identification
Quick walk of the deck to identify the material (cedar, pressure-treated, tropical hardwood, composite — brand if known), check the board condition (age, weather damage, end-grain rot, popped fasteners), and confirm the PSI and cleaner that fit. Composite brand is critical — high PSI on composite voids most warranties.
Deck Cleaner Scrub with 10-15 Minute Dwell
Sodium percarbonate deck cleaner on wood (Olympic Premium, Cabot Problem-Solver, Defy) or manufacturer-approved cleaner on composite. Brushed or sprayed on, allowed a 10-to-15-minute dwell time, scrubbed with a deck brush on stubborn spots before the rinse.
Rinse at Material-Correct PSI
Cedar and pressure-treated get a low-to-medium PSI with a 25-to-40-degree fan tip at 8-12 inches above the surface. Tropical hardwood gets much lower PSI with a wider fan tip. Composite gets the manufacturer-rated low pressure. The tech adjusts on the spot to the deck.
Optional Oxalic Brightener Neutralize
After the rinse, optional oxalic-acid brightener neutralizes the alkaline wash, balances wood pH, and brings back natural wood tone on cedar and pressure-treated. Recommended on decks older than five years or any deck that will be re-stained inside six months. Adds 30-60 minutes to the visit.
Full Board Walk with Screwdown and Fastener Replace
Walk the whole deck on hands and knees, screwdrive every popped fastener back into the joist, pull and replace corroded fasteners with stainless or coated equivalents. End-grain rot check at every cut end with borate treatment on small areas. Hidden-fastener plugs matched from truck stock where needed.
Same-Day Dated Photo Report
Before-and-after photos, fastener count (popped versus replaced), any end-grain treatments performed, any flagged items for follow-up (soft board, rusting hanger, missing baluster). Report goes to the homeowner the same day so the wash is documented and follow-up scope is on record.
Deck Pressure Wash & Restore Pricing
Final pricing depends on deck square footage, board material, the depth of the prep (wash only versus wash plus brightener versus wash plus brightener plus full screwdown), and any add-on scope (end-grain treatment on larger areas, large-volume fastener replacement). The wash scope does not include a stain coat — staining and sealing is a separate scope scheduled to a 48-hour rain-free dry window. Request a free estimate for an accurate quote.
Tell us the deck size and the material — we will quote the wash, the screwdown, and the optional brightener.
Why Handis for Deck Pressure Wash & Restore
A generic deck pressure wash in Seattle fails the same way most years — a single PSI setting for the whole job, sodium percarbonate at full strength on composite (which voids the warranty and etches the boards), high PSI on cedar that raises the grain so the next stain sheets right off, no brightener afterward so the wood is left alkaline and the next stain absorbs poorly. The Handis wash was built backward from the four most common deck-wash failures we get called to fix — composite warranty void, cedar grain raise, sticky alkaline finish under a fresh stain, and no follow-up screwdown so the popped fasteners are still popped a year later. The tech who washes your deck has done a thousand of these and knows what your specific board material needs.
PSI matched to the deck material, not a single setting
Cedar and pressure-treated get a different pressure than tropical hardwood; hardwood gets a different pressure than composite. Composite especially — Trex, TimberTech, Fiberon, and Azek all void the manufacturer warranty above the rated cleaning pressure (typically 1,500 PSI fan tip at 12 inches). Generic deck-wash crews use one PSI for the whole job and damage either the wood grain or the warranty. The tech sets the wand to the deck on the spot.
Cleaner sized to the material — sodium percarbonate on wood, manufacturer-approved on composite
Sodium percarbonate deck cleaner (Olympic Premium, Cabot Problem-Solver, Defy) is the right choice on cedar, pressure-treated, and tropical hardwood — it lifts moss, algae, leaf tannin, and surface gray without acid etching. On composite, sodium percarbonate at full strength is too aggressive and can leave the boards looking blotchy; composite gets a manufacturer-approved cleaner sized to the brand. We carry both classes on the truck and select on arrival based on the deck material.
Oxalic brightener neutralize where the next stain coat is coming
The deck cleaner wash leaves the wood alkaline. An oxalic-acid-based brightener (Cabot Problem-Solver Brightener, Defy Wood Brightener, or equivalent) neutralizes the wash, balances the wood pH back toward neutral, and brings back the natural wood tone. Brightener is optional on a wash-only visit but recommended on any deck that will be re-stained inside six months — the next stain absorbs significantly deeper and lasts longer on a properly neutralized surface. We quote brightener separately so the homeowner can decide.
Full board walk with screwdown — prevents the next service call
Freeze-thaw cycling in the PNW backs deck screws out a half-turn each winter; on a deck that has not been touched in five years, half the boards in the affected bays usually have at least one popped fastener. The walk takes 15 to 30 minutes per 200 sq ft and prevents the next service call. We replace corroded galvanized fasteners with stainless or HDG ceramic-coated equivalents from truck stock; hidden-fastener systems get the matched plug.
Honest scope — wash is not stain, and we will not pretend it is
The wash-and-restore visit is exactly that — wash, optional brightener, screwdown, end-grain check, photo report. It does not include a stain coat. Staining and sealing requires a 48-hour rain-free dry window plus a multi-day cure timeline and is a separate scope; we will book the stain visit separately when the homeowner wants it. Generic deck-restoration crews bundle the wash and the stain as a single visit and end up applying stain to a deck that is not dry enough or not properly neutralized — the coat peels by August. We will not do that.
Insured, background-checked, 30-day workmanship guarantee on the wash
Handis carries general liability and workers' compensation; every technician has cleared a background screening before the first job. The 30-day workmanship guarantee covers our work on the visit — if a fastener we set backs out, a hidden-fastener plug we replaced loosens, or a cleaner residue leaves a visible stain inside 30 days because of our application, we come back and correct it at no extra charge. Pre-existing damage, end-grain rot beyond the borate scope, and homeowner-caused damage outside the visit window are not workmanship issues.
Estimate
Tell us the deck square footage, the board material (cedar, pressure-treated, tropical hardwood, composite — brand if you know it), the deck condition (general grime, moss bloom, leaf tannin stains, heavy weathering), and whether you want brightener and screwdown in the package or just the basic wash. Send phone photos if you can — overall deck plus any close-ups of the worst areas help us pre-stage. We will quote the wash, the optional brightener, and the screwdown line by line so you can pick the package.
Customer Reviews
Recent deck pressure wash and restore reviews from verified Seattle-area customers.
1996 cedar deck off our Wedgwood house, hadn't been touched in three years — moss on the north side, leaf tannin stains, surface had gone solid gray. Handis washed with sodium percarbonate at low PSI, brightener after, screwdriven 34 popped fasteners back in, replaced 4 rusty ones with stainless. Deck looks like new cedar at the edges and back to original tone in the middle. No stain — we wanted to DIY the stain coat later. Honest scope.
Composite Trex Transcend deck off our Sammamish house. Previous handyman pressure-washed it at full power last year and left fuzzy patches everywhere on the boards. Handis tech showed up with a low-PSI wand and a Trex-approved cleaner, did the whole deck without raising a single fiber, screwed down two popped Cortex plugs, checked the perimeter for any other issues. Boards look as good as new.
2005 pressure-treated deck on our Renton split-level. Wanted to prep for a DIY stain in the spring. Handis came in October, washed at the right PSI for PT, brightener after, full screwdown, treated three small end-grain rot spots with borate, sent a photo report flagging two soft boards for replacement before the stain. We did the boards ourselves over the winter and stained in May. The wash was the right setup for our stain plan.
Big tropical ipe hardwood deck off our Capitol Hill house, maybe 480 sq ft. Hardwood is fussy — the previous wash crew had raised the grain badly. Handis tech used much lower PSI with a wide fan tip, oxalic cleaner, brightener, then the screwdown. Grain stayed smooth. Deck looks furniture-grade now. Honest scope — they did not try to upsell a stain coat we did not want.
Smaller cedar deck on our 1962 Bellevue split-level, maybe 180 sq ft. Just the wash-only package — we are not planning to stain anytime soon, just wanted the moss off and a clean look for summer. Tech finished in about two hours, was honest that we did not need the brightener since we were not staining within six months. Clean visit, no upsell. Deck looks presentable.
Frequently Asked Questions
Common questions about Handis deck pressure wash and restore — pricing, PSI, cleaner choice, brightener, screwdown scope, and the difference from a stain coat.