Every pressure washing company says the work is worth it. We would like to be more specific than that, including about the parts where the answer is "not really".
Where it genuinely protects something
Roof cleaning
The strongest case on the list, and not a close contest. Roof algae feeds on the limestone filler in asphalt shingles, holds moisture against the surface, and darkens the roof which raises its temperature. Manufacturers take it seriously enough to sell algae-resistant shingles with copper granules built in.
The arithmetic: cleaning costs a few hundred to around a thousand dollars. A roof replacement in this market is a five-figure job. Even a modest extension of service life makes that a sensible trade — and nobody has to exaggerate the numbers for it to hold up.
Annual house washing
The case here is about the finish rather than the structure. Algae and mildew accelerate the breakdown of paint and sealant, and organic growth holding moisture against a wall assembly year-round is not neutral. Repainting a Jacksonville home costs several thousand dollars; keeping the existing finish sound for longer has real value.
Wood decks and fences
Modest but real. Organic growth holds moisture in timber, and moisture in timber is what leads to rot. Cleaning wood before it goes grey and soft extends the useful life of a deck materially — and cleaning before staining roughly doubles how long the stain lasts.
Where it is genuinely just appearance
Which is a fine reason. It is just worth being honest that it is the reason.
- Driveways and walkways. Concrete is not harmed by being dirty. It is cleaned because a clean driveway transforms how a property reads from the street — and at $95 to $185 for a two-car drive it is the cheapest visible improvement available to most homes.
- Pavers. Same, unless weeds in the joints are actually displacing units.
- Vinyl fencing. Vinyl does not deteriorate from algae. It just looks green.
- Screen enclosures. Mostly appearance, though frame oxidation is worth staying ahead of at the coast.
The safety cases, which are neither
Two jobs sit outside the appearance-versus-protection framing, because they are about somebody falling over.
Pool decks and docks develop biofilm — a living slick that is nearly invisible and genuinely treacherous when wet. On a dock especially, where people walk carrying things, this is a real hazard rather than a presentational one.
Gutters belong here too, in a different way. A blocked gutter holds water against the fascia board, and fascia rot leads to carpenter ants and a repair costing many times what the clearing would have. This is the highest-return maintenance item on the whole list, and the least interesting to look at.
Where we would tell you not to bother
- Washing failed, chalking paint. Cleaning removes some of it and makes the failure more obvious. Paint it or leave it.
- Cleaning a roof at the end of its life. A worn roof looks worn once clean.
- Sealing pavers purely to sell. Buyers do not price it in.
- Anything nobody sees. The elevation facing a fence is not where the money should go.
- Cleaning something you are replacing this year.
The one number that holds up
Not a resale figure — those get quoted confidently and rest on very little. The reliable one is the difference between annual and reactive maintenance.
A house cleaned every year runs about $300 annually and needs a light mix and one pass. The same house cleaned every four years needs a stronger solution, longer dwell and often a second application — roughly $600 in one hit, with four years of biological activity on the surface in between. The frequency guide covers this properly.