About driveway & concrete
Concrete is porous. It absorbs oil, tyre rubber, leaf tannin and rust, and it grows the same algae that stains siding — which is what makes a driveway look grey and tired long before it is worn out.
Surface cleaner, not a wand
A flat surface cleaner is a rotating bar under a shroud that keeps the spray at a fixed height and speed. That is what produces an even finish. Cleaning a large slab with a handheld wand almost always leaves visible arc marks — the zebra striping you see on driveways done in a hurry — because it is nearly impossible to keep a wand perfectly consistent by hand over hundreds of square feet.
Stains behave differently from dirt
General grime lifts with pressure and detergent. Oil and transmission fluid have soaked into the pores and need a degreaser worked in and dwelt before rinsing, sometimes more than once. Rust from fertiliser or metal furniture needs a different treatment again. Deep or old stains may lighten substantially rather than disappear, and it is worth knowing that before the work starts.
Sealing afterwards
Sealing clean concrete slows how fast it re-stains and makes the next clean easier, because contaminants sit on the surface instead of soaking in. It is optional, it is a separate job, and it has to go on clean, dry concrete — sealing over dirt locks the dirt in.
What moves the price
- Square footage of driveway, walkway or patio
- Surface type — broom-finish concrete, stamped concrete, pavers and brick differ
- Oil, rust or paint stains needing pre-treatment
- Whether sealing is wanted afterwards
- Slope and drainage, which affect where the runoff goes
This is why a photo prices most jobs without a visit.