Deck cleaning and sealing typically costs $300-$900 for a 300-square-foot wood deck, with an average near $550. Total price depends on deck size, wood condition, cleaning method, sealer quality, labor rates, and whether repairs or old coating removal are needed.
| Item | Low | Average | High | Notes |
|---|---|---|---|---|
| Cleaning and sealing, 300 sq. ft. | $225 | $550 | $1,050 | Ranges from basic service to extensive prep and premium sealer |
| Combined price per sq. ft. | $0.75 | $1.85 | $3.50 | Wood deck, professional service |
| Cleaning only, 300 sq. ft. | $90 | $180 | $375 | May have a contractor minimum |
| Sealing only, 300 sq. ft. | $225 | $450 | $750 | Assumes the deck is ready for coating |
What a 300-square-foot wood deck usually costs
For a typical pressure-treated pine deck in serviceable condition, cleaning and sealing runs about $0.75-$2.50 per square foot, or $225-$750 for 300 square feet. The national planning average is around $1.85 per square foot, or $550 for that size. Higher quotes can reach $3.50 per square foot when the surface needs stripping, sanding, or several prep steps.
Most standard projects cost $400-$700 for a 300-square-foot deck with ordinary access and no major repairs. Prices generally include washing, drying time, and one coat of a standard water- or oil-based sealer. A second coat, railings, stairs, and hard-to-reach areas may be priced separately. Assumptions: standard wood decking, average U.S. labor rates, normal access, and no extensive coating removal.
How washing, prep, sealer, and labor shape the quote
Contractors may quote a combined rate or list each task separately. A written estimate should identify the cleaning method, included surfaces, sealer type, and whether sanding or stripping is included. The following ranges are typical for a 300-square-foot deck and vary by local labor and condition.
| Quote component | Low | Average | High | Typical basis |
|---|---|---|---|---|
| Cleaning and brightening | $90 | $180 | $375 | $0.30-$1.25 per sq. ft. |
| Labor for prep and application | $150 | $300 | $525 | $35-$75 per hour |
| Sealer and application supplies | $75 | $150 | $300 | $0.25-$1.00 per sq. ft. |
| Sanding or old-finish removal | $0 | $150 | $450 | $0-$1.50 per sq. ft. |
| Travel, setup, or minimum charge | $0 | $50 | $150 | Often applies to small jobs |
Labor and surface preparation usually make up more of the bill than the sealer itself. For a labor estimate, a crew might spend 4-8 hours washing, preparing, and applying product, plus drying time between steps.
Why deck size, wood type, and coating condition change the price
Square footage is a starting point, but deck shape and details affect labor. A simple 200-square-foot platform is faster to treat than a 300-square-foot deck with tight balusters, built-in benches, and multiple stair runs. Railings are sometimes charged by linear foot, commonly $2-$5, or included in a higher square-foot rate.
Expect prep costs to rise when the deck has peeling stain, deep mildew, or weathered boards. Light washing may add only $0.30-$0.75 per square foot; stripping old finish or sanding can add $0.75-$1.50 per square foot. Cedar and redwood can require gentler cleaning and compatible products. Composite decking generally needs cleaning rather than sealing; applying a wood sealer to composite boards is usually unnecessary and may violate product guidance.
Decks above 500 square feet may receive a lower per-square-foot rate because setup costs are spread across more area. Conversely, steep terrain, limited water access, nearby landscaping, or elevated decks can add roughly 10%-30% for extra protection and difficult access. Threshold example: a deck with more than 100 linear feet of railing or over 20 stair treads often needs a separate labor allowance.
Which prep choices can lower a deck sealing estimate
Getting the deck cleared of furniture, planters, grills, and loose debris can reduce billable setup time. Homeowners should confirm whether the contractor expects them to move these items or includes that work. Keeping the job to cleaning and one suitable coat, when the surface allows, can also avoid unnecessary sanding or premium product upgrades.
Ask whether the current finish needs stripping before approving a full removal charge. A small test patch can help determine whether cleaning and a compatible sealer will work. Do not skip prep that is necessary for adhesion, and avoid applying sealer before boards are fully dry. Compare quotes using the same scope, product type, number of coats, and included railings so a low bid is not simply missing work.
How regional labor rates affect deck cleaning prices
Labor-market differences can shift a quote substantially. In lower-cost rural and Midwestern markets, many straightforward projects fall near the lower half of the national range. Major metropolitan areas in the Northeast, West Coast, and parts of the Mountain West may run 15%-35% higher because of wages, travel, and operating expenses. Local climate also matters: humid or shaded decks may need stronger mildew treatment and more prep.
Use regional differences as a comparison range, not a substitute for a local inspection. Some contractors set a minimum charge of $150-$300, so small decks can have a higher per-square-foot price. Ask whether the estimate includes sales tax, water use, and protection for siding, plants, and nearby outdoor surfaces.
When removal, repairs, or stairs add separate charges
Washing and sealing do not restore damaged boards. Replacing a few boards may add $15-$35 per linear foot installed, depending on lumber type, access, and whether matching material is available. Minor fastener or board repairs may add $75-$250; structural repairs require a separate assessment and can cost considerably more.
Check that disposal and coating removal are itemized rather than assumed to be included. Removing failing stain can add $150-$450 on a 300-square-foot deck, while hauling damaged lumber or heavy debris may cost $50-$200. Stairs, lattice, and privacy screens may be measured separately because they take more time per treated surface area than open decking.
Three sample quotes for common deck sizes
The examples below show how scope changes the total. They assume ordinary access and professional labor; local quotes can differ. Hourly labor figures are planning estimates rather than fixed contractor rates.
| Project | Scope and labor | Rate basis | Estimated total |
|---|---|---|---|
| Small 150-sq.-ft. deck | Wash and one coat, 4 labor hours | $1.50 per sq. ft. plus $50 minimum setup | $275 |
| Standard 300-sq.-ft. deck | Clean, light sanding, seal, 7 labor hours | $1.85 per sq. ft. | $555 |
| Large 500-sq.-ft. weathered deck | Strip, wash, seal, 14 labor hours | $2.80 per sq. ft. | $1,400 |
The weathered deck example costs more because finish removal adds labor, not simply because it is larger. Before accepting a quote, check the measured area, included rails and stairs, product coverage, drying schedule, and any extra charge for repairs or disposal.
How often wood decks need resealing and what it costs
Many wood decks need resealing every 2-3 years, though direct sun, heavy rain, snow, and foot traffic can shorten that interval. A maintenance wash and fresh coat may cost less than the first service if the existing finish remains sound. For a 300-square-foot deck, a lighter maintenance visit might run $225-$500, while a neglected surface can return to the higher prep-and-sealing range.
Regular inspection helps distinguish routine maintenance from a project that needs stripping or board replacement. Water that soaks into the wood rather than beading, widespread fading, and peeling finish indicate that the surface may need attention. Follow the sealer label for recoat timing and avoid coating damp wood, which can reduce adhesion and lead to early failure.