Salt film and algae are two different problems on the same wall
Almost every exterior on the Grand Strand is carrying both, and they are not fixed the same way, which is why one homeowner gets a year out of a wash and the neighbor two streets over feels like nothing happened. Salt arrives as aerosol. Onshore wind lifts it off the surf and carries it well past the first row of houses, and it settles as a fine, even haze that dulls glass, screens, and siding without ever turning a color. Algae is a living colony. It needs shade and damp to hold, so it shows up as green or blackish patterning exactly where the sun does not reach - the north elevation, the wall behind the stair, the strip of siding a palmetto keeps in shadow all afternoon.
The tell is the pattern. If the whole windward face looks flat and tired but the shaded corners look no worse than anything else, that is salt, and it comes off with surfactant and a rinse. If one elevation is clearly greening while the sunny side looks fine, that is growth, and rinsing it only knocks the visible layer down - the organism survives and it is back within a season. That one needs chemistry that kills it at the root, applied at low pressure. A house in Cherry Grove or Garden City that faces the water often wants a plain rinse more often than it wants a full soft wash, and knowing which of the two you are looking at is most of the decision.
When the siding is not dirty, it is chalking
Vinyl is the dominant siding here, and it takes years of hard coastal UV. Eventually the binder at the surface starts to break down and release a fine powder. Run a dark cloth or your forearm down a sunny wall: if it comes away white, that is oxidation, not soil. This matters because it is the one exterior complaint that washing genuinely cannot solve. A cleaning removes the loose chalk and the wall does look better for a while, but the faded, thin look is the material itself aging, and the color is not coming back. Pressure makes it worse - forcing water at an already-degraded surface strips more of it and speeds the next round.
What honestly helps is a cleaning that clears the chalk paired with an oxidation treatment that restores some depth to the surface, and past a certain point the answer is paint or replacement rather than any wash. We would rather tell you that on the walkthrough than sell you a service that will disappoint you two weeks later. Plenty of Grand Strand homes are somewhere in the middle, with a chalked sunny elevation and three sides that only need a normal soft wash, and that is a perfectly reasonable job to do.
The rental calendar decides the right week to wash
A large share of the Strand turns over as short-term rental, and that changes the timing question from "how often" to "when." The two windows that actually work are late winter into early spring, before the season fills, and the shoulder once the crowds thin in the fall. Trying to wash a booked property mid-summer means wet walkways, a closed deck, and guests routed around equipment on the one week they came for.
Pollen is the other half of the timing. If you wash before the spring drop finishes, you are paying to clean a surface that is about to be coated again - and the yellow film that follows makes it look like the work was never done. Waiting until the drop is over costs you a couple of weeks and gets you a finish that holds into the season. For owner-occupied homes away from the rental blocks the calendar is looser, but the pollen rule still applies, and so does the simple one: clean before growth digs into the pore, not after.
After a storm, most of what looks like damage is deposit
Exteriors here look far worse after a blow than they usually are. Driven rain packs leaf litter against the base of the siding, sand works into screens and window tracks, and marsh silt collects in every low corner of a driveway or patio. It reads as ruin and is mostly material sitting on the surface.
The part worth doing first is not the cleaning, it is clearing anything packed against wood or siding. A wet mat of leaves held against a fence rail or banked up along the bottom course of siding keeps that spot damp for weeks and is how a cosmetic problem turns into a rot problem. Once that is off, a normal wash handles the rest. The exception is worth stating plainly: if wind-driven water got behind the siding or under the roof edge, no amount of cleaning addresses that, and anyone telling you a wash will is selling you the wrong thing. We will say so, point you at what actually needs a repair, and clean what is genuinely dirty.
