The difference in one line
Pressure washing cleans with force. Soft washing cleans with chemistry: a low-pressure application of a cleaning solution that kills the algae, mold and mildew, followed by a gentle rinse. On organic growth, which is most of what turns coastal NC houses green, killing it at the root lasts longer than blasting the surface.
What the manufacturers say
| Surface | Manufacturer / industry guidance |
|---|---|
| Vinyl siding | The vinyl siding trade association says a pressure washer can be used with caution, but never aim the stream upward, because water gets driven behind the panels. Some siding makers cap pressure or advise against it entirely.1 |
| Fiber cement (e.g. HardiePlank) | James Hardie: don't use a high-pressure power washer. A garden-hose rinse every 6–12 months is its basic care advice.2 |
| Asphalt shingle roofs | The Asphalt Roofing Manufacturers Association says not to use a power washer, brush or broom, and that high-pressure systems are likely to damage asphalt roofing.3 Owens Corning likewise says not to scrub or use high-pressure power washing equipment, because it loosens the protective granules.4 |
| Composite decking (Trex) | Trex allows up to 3,100 psi on its current boards with a fan tip held at least 8 inches away. More than that can damage the boards and void the warranty.5 |
| Wood decks | The USDA Forest Products Laboratory notes power washing can remove wood from the surface, especially softer woods like cedar.6 |
So which surfaces get which?
- Soft wash: vinyl, fiber cement and painted siding, stucco, soffits, roofs, screened enclosures, and most wood.
- Controlled pressure: concrete driveways, sidewalks, patios and pool decks, ideally with a rotary surface cleaner for an even, stripe-free finish.
- Case by case: composite decks and fences, which get the maker's limits and a wide fan tip.
Why the “just blast it” approach fails here
High pressure can make green siding look clean for a while. But if the growth isn't killed, it comes back fast in eastern NC's humidity, and you may have driven water behind the siding, etched soft wood or stripped roof granules in the process.
That is why Ray-Nor-Shine soft washes houses and roofs and saves the surface cleaner for concrete. See our house washing and roof cleaning pages for how a visit runs.
Want a real number for your house?
We give free, no-pressure quotes across Onslow and Pender counties — usually the same day you call.
Get a Free Quote Call (910) 333-7369
We work in Jacksonville, Richlands, Swansboro, Sneads Ferry, Holly Ridge, Hampstead, Surf City, and by scheduled trip to Topsail Island and the Crystal Coast.
Sources
- How to Clean Vinyl Siding — Polymeric Exterior Products Association (formerly the Vinyl Siding Institute)
- Tips for Cleaning Your Siding (2024) — James Hardie
- Algae Discoloration of Roofs (technical bulletin, 2024) — Asphalt Roofing Manufacturers Association
- Algae Resistance and Roof Cleaning (2023) — Owens Corning Roofing
- How to Clean a Trex Deck — Trex
- Finishes for Wood Decks (FinishLine, rev. 2013) — USDA Forest Service, Forest Products Laboratory
Prices quoted from national sources are averages, not our rates. Every home is different — call for a free, no-pressure quote.