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Getting North Carolina red clay off concrete, and keeping it off

Red clay is not dirt sitting on your driveway. It is iron oxide that has soaked into the pores, which is why rinsing does nothing and why the fix is chemical.

♀ Woman-Owned★ 4.9 · 213 reviewsLicensed & InsuredSince 2010
Concrete 6 min read

The short version

  • The orange stain is iron oxide, and it has soaked into the pores of the slab rather than settled on top of it.
  • Water and pressure alone will not lift it. The iron has to be broken chemically first.
  • New construction is the worst case, because graded clay gets tracked across concrete that has never been sealed.
  • Sealing a clean slab is what stops it from happening again.

Why it stains when regular dirt does not

Piedmont clay is red because it is full of iron. When clay-heavy runoff sits on concrete, the water carries fine iron particles down into the pore structure of the slab and then evaporates. The iron stays, oxidizes, and bonds. What you are left with is not a layer on the surface. It is a stain inside the top of the concrete.

That is the whole reason a garden hose accomplishes nothing. You are rinsing above the problem.

It is worst on new construction, which is most of what has gone up around Flowers Plantation, Corinth Holders, and the new sections of Clayton. Grading exposes raw clay, rain moves it across a fresh driveway, and fresh concrete is at its most porous. A first year house can look years older than it is for exactly this reason.

What actually removes it

Iron stains come out with an acid or a rust-specific remover that breaks the iron bond, followed by agitation and a controlled rinse. Not more pressure. Pressure that is high enough to grind out an embedded stain is high enough to etch the surface, and etched concrete is permanent, uneven, and holds the next stain better than it held the last one.

1

Identify the stain

Red clay, rust from a downspout or a metal chair, and battery acid all look similar at a glance and take different chemistry. Guessing wrong wastes a treatment and sometimes sets it.

2

Pre-wet and protect

Beds and grass get soaked so nothing acidic settles on roots, and the slab is wetted so treatment spreads evenly instead of flashing in the sun.

3

Treat the iron

The remover goes on and gets dwell time. This is the step doing the actual work, and it cannot be rushed by adding pressure.

4

Surface clean and neutralize

A flat surface cleaner passes at a pressure the concrete can take, so the finish is even edge to edge without the striping a wand leaves. Then we neutralize and rinse.

An older stain that has been through several summers may lighten dramatically without disappearing entirely. Concrete that has been stained for years and never sealed can hold a shadow. We will tell you that on the walkthrough rather than after you have paid.

The step most people skip

Cleaning is half of it. A bare slab goes right back to absorbing the next storm, and around here there is always a next storm. Sealing fills the pore structure so clay, oil, and leaf tannins sit on the surface where a hose can reach them.

The right time to seal is immediately after a clean, once the slab has dried through. Everything is already prepped at that point, which makes it the cheapest sealing you will ever buy. On a driveway in the Triangle, expect a few years out of a good sealer, longer on a covered porch or a patio.

Keeping clay off in the first place

  • Redirect downspouts so roof water is not sheeting clay runoff across the drive.
  • Get grass, straw, or mulch established on bare graded areas uphill of the concrete.
  • Rinse fresh clay before it dries. Wet clay is a rinse and dried clay is a treatment.
  • Move metal furniture and planters off the slab, or put feet under them. Rust rings are a separate stain and they set fast.
  • Wash the lower siding at the same time. Clay splashes up the first two feet of every wall facing the drive.

We clean and seal concrete across Johnston and Wake County. If your driveway went orange in its first year, that is normal here, and it comes back. Call (919) 698-3669.

Our work

What this looks like finished

Stamped concrete patio with a wet-look finish after cleaning and sealing
Stamped concrete, sealed
Stamped concrete driveway apron cleaned in front of a suburban home
Stamped concrete driveway
Brick paver patio being surface cleaned, clean pavers emerging beside dirty ones
Paver patio, surface cleaning
Questions

Asked and answered

Will red clay stains come out completely?
Most do, especially anything from the last year or two. A stain that has been sitting on unsealed concrete for many seasons can leave a faint shadow. We will tell you which one you have before we start.
Can I use household bleach or vinegar on it?
Bleach does nothing to iron. Vinegar is too weak to break the bond and strong enough to dull the surface if you leave it on. Neither is worth the afternoon.
Does pressure washing remove clay stains?
Pressure removes what is on top. Clay is in the pores, so it needs chemistry first. Pressure alone at the level it would take to cut an embedded stain will etch the concrete permanently.
Should I seal my driveway after cleaning?
If you want to stop repeating this, yes. Seal after the clean, once the slab is fully dry. That is when the prep work is already done and the cost is lowest.
How soon can a new driveway be cleaned or sealed?
Cleaned any time. Sealed after the concrete has cured, usually about a month on new pours. Sealing too early traps moisture in the slab.
Services

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Where we work

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Reviews

What neighbors say about the work

★★★★★

“Did a great job on our pavers and driveway. Got out sap and pollen I did not think would ever come up.”

Oscar Gonzalez · Garner
★★★★★

“Long driveway with years of clay stains. It came out even end to end with no stripes anywhere.”

Derrick Hall · Fuquay-Varina
★★★★★

“One of the most professional and organized companies I have worked with. Driveway looks incredible.”

Corey Cox · Smithfield
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