Driveway and Concrete Cleaning: What Works, and Should You Seal It After?

Why concrete looks striped after DIY washing

A handheld wand cleans a narrow fan of concrete at a time, and the distance from the surface keeps changing. Every pass shows, and you get “zebra stripes.” Professionals use a rotary surface cleaner, a spinning bar under a hood held at a fixed height, so the whole slab cleans evenly. Then the edges are detailed and the surface is rinsed.

Pre-treat the stains that pressure alone won't lift

• Organic growth: green and black algae and mildew in shaded areas get a cleaning solution first.
• Oil and drips: a degreaser before washing.
• Rust and irrigation stains: orange marks from well water and sprinklers usually need a dedicated rust remover.

Some old stains lighten rather than disappear. A good company tells you that up front.

Should you seal after cleaning?

Sealing is optional. Concrete Network notes a driveway sealer may last 1–3 years depending on the type and exposure, and the surface must be clean and dry before it is applied.¹ It also notes that most sealers pass dry slip tests but can be slippery when wet, while penetrating sealers won't make the surface more slippery.¹ On a sloped driveway or pool deck, a penetrating sealer is usually the safer pick.

Where the wash water goes

NC water-quality guidance points out that water entering a storm drain is not treated. It flows straight to surface waters, which on the coast means creeks, the sounds and the ICW.² That guidance, written for wash operations, recommends:

• washing over grass or gravel where possible
• covering storm drains
• using biodegradable detergents in the pH 6–9 range²

Ask any company how they handle runoff, especially near the water.

Bundle it

Driveways, walkways, patios and pool decks are the most common add-ons to a house wash, since the rig is already on site. See driveway and concrete cleaning for before-and-after photos.