Wood or composite: identify the deck first
I start by asking for the board brand, installation paperwork, and the last stain or sealer used. Pressure-treated pine, dense ipe, uncapped composite, capped composite, and PVC require different decisions. Manufacturer markings on a safely accessible board edge or spare piece can help; appearance alone can mislead.
A water-drop test on clean, dry wood gives a clue about absorption: beading suggests water resistance, while soaking-in suggests exposed, absorbent wood. It does not identify the species, prove that a coating is compatible, or replace a moisture-meter reading before staining.
Cleaning wood without carving the grain
Clear furniture, sweep leaves, and inspect for soft boards, splinters, and loose fasteners. Protect surrounding plants and finishes. Apply a compatible wood cleaner, allow the labeled dwell time, gently brush with the grain, and rinse. Cleaner and brightener are separate steps, not ingredients to mix together.
Where washing equipment is permitted, use a wide fan, keep it moving with the grain, and test inconspicuously. YellaWood recommends low pressure and a 45-degree fan. A suggested 500–1,200 PSI range is not a universal safe setting: weathered pine can scar even at modest pressure, and nozzle distance matters. READY SEAL’s preparation instructions specify 1,000 PSI or less.
I do not assume ipe needs more force because it is hard. DeckWise’s hardwood guidance recommends avoiding power washing and describes cleaning followed by an oxalic-acid brightener and thorough rinsing. Use the chosen system’s sequence and protective equipment. Never combine an acid brightener with chlorine bleach.
Composite cleaning: the brand sets the limits
Start with debris removal, the approved cleaner and brush, and gentle rinsing. “Soft wash” should describe controlled application, not permission to apply a house-wash mixture. Sodium percarbonate is an oxygen-bleach ingredient, but an oxygen-based cleaner is not automatically approved for every composite cap.
TimberTech’s care instructions recommend its cleaner for current collections and reject some generic composite cleaners. They permit power washing for rinsing only, with a fan tip and a maximum of 1,500 PSI. Older collections have different cleaner recommendations.
Trex’s official guide allows up to 3,100 PSI on specified newer lines, with a fan tip at least eight inches away; it advises against pressure washing early-generation composite. These are product-specific limits, not targets. Scrubbing and a hose often make more sense. Excessive force or incompatible chemicals can permanently mark boards and jeopardize coverage for the resulting damage.
Why mildew returns in shady places
Shade slows drying, while leaves, pollen, and trapped dirt keep feeding surface buildup. A deck can become slippery without looking dramatically dirty. I pay particular attention to stair treads, the space behind planters, and boards beside the house.
Sweep regularly, clear board gaps without damaging them, move moisture-trapping items, and correct irrigation that repeatedly wets the deck. Use a material-compatible mildew treatment when needed. Cleaning removes existing buildup; it does not permanently change the shade, drainage, or humidity. Recurring growth calls for better maintenance, not progressively stronger chemicals.
Staining and sealing after cleaning
Semi-transparent stain lets more wood grain show; solid-color stain gives an opaque appearance. Either needs a sound, compatible surface. An old film-forming finish may require stripping or sanding before a different coating. Dense hardwoods need products approved for that wood, not a generic promise that every sealer penetrates equally.
Plan finishing within the product’s preparation window, often during the following dry days, but never seal damp wood just to meet a deadline. Florida humidity, shade, and afternoon rain can extend drying. READY SEAL’s application guidance calls for a moisture meter and wood moisture of 12% or less; other coatings have different requirements.
I use one to two years as a review interval for renewing many exposed wood-deck finishes, with annual inspections and earlier attention when wear appears. It is not every product’s service life. Composite normally does not follow a wood staining schedule. Follow its manufacturer before applying any coating.
Jacksonville costs: cleaning versus restoration
About $150–$400 is a general planning range for straightforward residential deck cleaning, not a Safe Touch quote or a surveyed local average. As one comparison, a Jacksonville-area provider publishes $150–$300 for basic cleaning and higher restoration tiers. Size, rails, stairs, access, material, and condition change the work.
Ask whether the estimate includes brightening, stain removal, sanding, or sealing; those can be separate. Use Safe Touch’s exterior pressure-washing service page to discuss the deck material and an appropriate scope. Wood is not cleaned like driveway concrete.
Railings, stairs, and slippery algae
Keep people and pets away from wet treatment areas, wear suitable footwear and the cleaner’s specified protection, and keep hoses off walking routes. Stop if a railing moves or a stair feels unsound. Cleaning can expose deterioration, but it cannot restore structural strength. Have unsafe components repaired before using or washing the deck.