Percarbonate
Sodium percarbonate is a solid granular compound that releases hydrogen peroxide and soda ash when dissolved in warm water — essentially an oxygen-based bleach. Unlike chlorine bleach, percarbonate does not contain chlorine, does not off-gas toxic fumes, and breaks down into water, oxygen, and soda ash after use. It is the primary chemistry behind most "wood-safe" deck, fence, and cedar-shake cleaners on the market.
In depth
In exterior cleaning, percarbonate is the go-to choice for wood restoration because it lifts gray, weathered lignin from the surface of the wood without the fiber damage caused by chlorine. It is also used on stone, brick, and masonry where chlorine bleach could etch or react with the substrate. Percarbonate works best with warm water and a 10-20 minute dwell time, followed by a gentle rinse and a neutralizing acid brightener to restore the wood's natural color.
How this shows up on our jobs
We use sodium percarbonate on cedar shake siding, wood decks, fences, and any wood restoration project where chlorine would over-bleach or damage the wood fibers.
Services where this matters
Related terms
Sodium Hypochlorite
Sodium hypochlorite (NaOCl) is the active ingredient in household bleach and the primary disinfectant used in professional soft washing. It is sold to exterior cleaners in 12.5% concentration (commonly called "SH" or "pool shock"), roughly twice the strength of consumer bleach. When applied in a properly mixed soft-wash solution, it kills algae, mold, mildew, lichen, and bacteria at the cellular level within minutes and breaks down into salt water and oxygen.
Oxidation
Oxidation is the chemical reaction between a surface and oxygen (plus UV light, moisture, and time) that produces a chalky, faded, or dulled appearance. On vinyl siding, oxidation shows up as a powdery white residue that rubs off on your hand. On fiberglass doors and garage doors, it is a milky film that makes the surface look faded. On aluminum gutters, it appears as a crusty, chalk-like coating called "tiger striping" when rain streaks it. On painted metal, oxidation is the precursor to true rust.
Alkaline Cleaner
An alkaline cleaner is a high-pH detergent (typically pH 10-14) that dissolves oil, grease, fats, protein stains, and atmospheric grime by saponifying fatty acids and emulsifying petrochemical contaminants. The most common alkaline ingredients in exterior cleaning are sodium hydroxide (caustic soda), sodium metasilicate, and potassium hydroxide, often combined with surfactants, chelators, and dye. Alkaline cleaners are the counterpart to acid cleaners — pros reach for alkaline chemistry when the stain is organic or petrochemical, and acid when the stain is mineral.
Acid Wash
An acid wash in exterior cleaning is the application of a dilute acidic solution — most commonly muriatic (hydrochloric), phosphoric, oxalic, or a proprietary masonry blend — to dissolve mineral-based staining that bleach and surfactants cannot touch. Typical targets include efflorescence on brick, heavy rust from fertilizer or irrigation, mortar haze on new brickwork, mineral deposits on glass, and battery acid on concrete. Acid wash is not a general cleaning method — it is a targeted chemistry tool for specific stains on specific substrates.
Soft Wash
Soft washing is a low-pressure exterior cleaning method that uses biodegradable detergents and a controlled bleach solution to kill the algae, mold, mildew, and bacteria that cause staining — rather than scouring them off with brute force. A soft wash rig delivers cleaning fluid at roughly 60-200 PSI, comparable to a strong garden hose, which is safe on siding, shingles, painted surfaces, screens, and caulking. The chemistry does the work: the solution dwells on the surface, breaks down the organic growth at the cell level, and is then rinsed clean with fresh water.