Stained Concrete Floors

Acid stain, water-based stain, or dye

Acid stain (also called reactive or chemical stain) contains metallic salts in a mild acid solution. It reacts with the lime and minerals already in the concrete, and that chemical reaction creates the color. Water-based stain works more like a very thin, penetrating pigment. It seeps into the pores and deposits color without any reaction.

There is a third product that gets lumped in with these two and behaves differently from both. Dye uses pigment particles far smaller than a stain's, dissolved in a carrier rather than suspended in one, so they penetrate almost regardless of how open the surface is. Dye does not react with anything. It is the colorant polishing contractors reach for, and the one with the shortest outdoor life.

Here is how the three compare across the things that actually matter:

Dye earns its place on polished floors and loses it outdoors. Prosoco's Nathan Savage told For Construction Pros that "traditional polishing contractors typically opt for a penetrating, translucent dye", while Curecrete's Chad Talbot put the limitation bluntly in the same piece: "The dyes will disappear under UV light," where an acid stain "may lighten slightly under UV light, it won't disappear like a dye would." Ameripolish's Cabot summed up the other side of the trade in one line: "Stains are reactive," producing an unpredictable color. That is the whole decision. Dye gives you the color you picked and will not hold it in sun; acid stain holds its color for the life of the slab and will not give you exactly what you picked.

One catch with acid stain: it depends on minerals in the concrete to react. On a fresh, mineral-rich slab it can look incredible. On an old, worn, or previously coated floor where those minerals are spent, the color can come out patchy or barely there. Water-based stain doesn't care about the slab's chemistry, which is part of why it's so popular for renovations.

Acid stain also rusts any metal it touches almost instantly, and it has to be neutralized after it cures or your sealer won't bond. Water-based stain skips both headaches. It's low in VOCs and usually cures in an hour or two.

Color options, and the colors acid stain does not have

Acid stains live in the earthy end of the spectrum, and the range is genuinely short. The two best-known lines each publish ten standard colors: Kemiko's Stone Tone and Brickform's Blush-Tone. Here is the Stone Tone range grouped by family, which is a fair picture of what reactive stain can do.

Brickform's Blush-Tone line covers the same ground under different names. Concrete Network's color chart shows five of its ten: Jade, Turquoise, Coffee, Caramel and Mahogany.

What is not on that list

No gray. No beige. No white, no pastel, no true blue, no bright anything. This is the single most common disappointment with acid stain, and it is not a brand problem: the color comes out of a reaction between metallic salts and the lime in your slab, and that reaction only produces oxides in the brown, tan, rust, olive and blue-green range. If you want a gray, a greige, a soft neutral or a saturated color, you are shopping for water-based stain or dye, not acid stain. Water-based stain opens the whole box: reds, deep blues, charcoal, cream, even black and near-white, and you can layer or blend them. If the floor has to match cabinets or a wall, water-based is the safer bet because what you buy is close to what you get. Some pros use both on one floor, a water-based base for consistent color with acid stain over it for organic accents.

Why the swatch is not what you get

Every acid stain chart carries the same quiet caveat, and it is worth reading twice. Concrete Network puts it plainly: acid and water-based stains each produce a color unique to the surface they are applied to, and the only way to know yours is to test the color on a small, out-of-the-way patch before you commit the floor. The same page notes that dye samples look different again over polished concrete or a skim coat than over the gray concrete the swatch was shot on.

Three things on your slab move the result. Cement chemistry decides how much there is to react with, which is why the same color lands darker on one pour than another. Age and wear spend those minerals, so an old or previously coated floor often takes acid stain patchily or barely at all. Finishing matters too: a hard-troweled surface is closed and takes less stain than one that was floated. A printed swatch knows none of this. Treat the chart as the family you are buying, not the color.

Acid wash is not acid stain

These two get searched for interchangeably and they are opposite jobs. Acid staining adds color. Acid washing, also called acid etching, takes material away: it removes the top skin of the slab to open the pores, which is surface prep for a coating rather than a finish in itself. Concrete Network files it under surface preparation, not under decorative concrete, and that is the right shelf for it.

The part that matters if you are staining: acid washing a slab before you acid stain it weakens the stain's ability to bond. Etching strips out the very minerals the reactive stain needs. Etch only ahead of a non-reactive colorant, a water-based stain or a coating. If the floor is dirty, clean it; do not reach for acid out of habit.

Where acid washing does belong, the working mix is one part acid to ten parts water, acid poured into the water and never the reverse, neutralized afterward with about a pound of baking soda to five gallons of water, then rinsed. Hydrochloric or muriatic acid is the harsh option, phosphoric the milder one, and vinegar is too weak to do anything. Grinding is often just as effective and a good deal less disruptive, which is why most coating work has moved that way. Our guide to painting a concrete floor covers etching in that context, where it is the right tool.

How to stain a concrete floor, step by step

The stain is only as good as the prep. Skip the cleaning and you'll see every skipped inch later.

1. Clean and degrease. Strip off any old sealer, wax, glue, paint, or coating, then scrub the slab with a concrete cleaner or degreaser. Rinse and let it dry fully. Stain will not penetrate through oil, adhesive, or sealer, so this step decides your result more than any other.
2. Test a patch. Always stain a hidden corner or an offcut first. This is doubly true for acid stain, since the reaction depends on your specific slab. What you see in the test is roughly what the whole floor will do.
3. Apply the stain. Spray it on with an acid-resistant pump sprayer or work it in with a brush or sponge for more control. Keep a wet edge and work in sections so you don't leave overlap lines. Two thin coats usually beat one heavy one.
4. Neutralize (acid stain only). Once the reaction has run its course, scrub the floor with a baking soda and water solution to neutralize the residual acid, then rinse until the water runs clear and let it dry. Water-based stains skip this step entirely.
5. Seal it. Once the floor is bone dry, lock in the color with a sealer. This is not optional. It's what protects the stain from wear, spills, and UV. See the section below for how to choose.

Sealing and maintaining a stained floor

Stain colors the concrete, but it doesn't protect it. A sealer does that job, and a stained floor without one will scuff, water-spot, and wear far faster. Choose your topcoat based on traffic and where the floor lives. Our concrete floor sealing guide walks through acrylic, epoxy, and polyurethane options.

Upkeep is light. Sweep regularly, damp mop with a pH-neutral cleaner, and avoid harsh acidic products that eat the sealer. Our concrete floor cleaning guide covers the routine. Reapply a topcoat every two to four years in busy areas, and a stained floor can last the life of the house. Neglect the sealer and you're looking at closer to twenty years before the color starts to go.

Cost of stained concrete floors

Staining is one of the cheaper ways to finish a slab, which is a big part of its appeal.

Going DIY, the stain itself runs about $35 to $60 per gallon, and a gallon covers roughly 200 square feet. A complete kit for a 200-square-foot room, stain and sealer included, lands around $175 to $200, or about $0.20 to $0.40 per square foot for materials alone.

Hiring a pro, expect roughly $3 to $15 per square foot with labor included, and the number climbs with complexity:

• Basic, single color, minimal prep: about $3 to $6 per square foot
• Intermediate, one or two colors: about $6 to $11 per square foot
• Upgraded, multiple colors and sawcut patterns: about $11 to $16 per square foot
• High-end, stencils and hand-applied detail: $16 to $25 or more per square foot

Sealing usually adds $1 to $3 per square foot if it's billed separately. Run your room through the concrete floor calculator for square footage, then build a full budget with our concrete floor cost guide.

A real DIY note from a homeowner on the TractorByNet forums: they acid-stained a new slab using concentrated stain, sprayed it on and wiped it off, and stressed the concrete "had to be perfectly clean and free from oil, grease, and adhesives." Years later they reported "nothing but positive comments on everyone that has seen the floors." Prep is the whole game. Staining a patio or walkway outdoors has its own rules, set out in outdoor concrete floors.

The six ways to color concrete, and which are permanent

Stain is one of six, and knowing where it sits explains most of what follows.

A useful way to hold it: the first two put color in the concrete, the middle three put color into it, and paint puts color on it. Durability falls off in that order. If you want color that cannot fail, it has to go in before the pour, which is a mix decision rather than a finishing one.

Integral color is dosed by weight, and there is a ceiling. Pigment is batched as a percentage of the cementitious material: 2 to 4 percent is the working range, and the color saturation point is about 7 percent, beyond which more pigment buys no more color. ASTM C979, the pigment specification, caps the dosage at 10 percent of cement mass. Carbon black saturates much lower, around 2 percent.

At those doses pigment does not weaken concrete. A 2024 study found 28-day strength rose by 7 to 15 percent with iron oxide pigment at 2 to 6 percent, because the particles are far finer than cement and densify the paste. Strength loss comes from replacing cement with pigment, not from adding it.

Quikrete's consumer Liquid Cement Color works differently: it is dosed per bag rather than per weight of cement, one 10 oz bottle coloring up to two 60 or 80 lb bags, with a hard limit of one bottle per 60 lb bag. Since Quikrete does not publish the cement content of a bag, you cannot convert that into a percentage, compare it to the professional range, or push the color past the bottle limit. The same bottle in concrete mix, mortar mix and sand mix will also give three different shades, because those products have three different cement fractions.

Why color matching fails, and what to do instead

This is the expectation to set before you start, because it is the single most common disappointment with colored concrete.

Acid stain cannot be matched at all, and the manufacturers say so themselves. The color is the product of a chemical reaction between metallic salts and the free lime in that particular slab, so it depends on how much lime is where, which no two slabs share. Walt Tools states its acid stains "will not produce a uniform color or appearance" and that results "will vary unpredictably". Scofield says the "final color produced is unique to each surface". Brickform adds the detail that catches people out: "the color of the material in the bottle is not representative of the resulting color after the stain has completely reacted with the concrete."

That unpredictability is the look. If you want an even, specified color, acid stain is the wrong product.

Integral color is repeatable in principle and still drifts in practice, because pigment dose is one variable among at least seven:

• Water. More water lightens the color substantially. NRMCA: "concrete with a higher w/cm will generally be lighter in color." A driver adding water on site to make a load workable will visibly lighten that load.
• Cement source. PCA advises cement "of the same type and brand from the same mill" for the whole job, because gray cement's own color varies with clinker source. Slag gives a greenish cast at first, silica fume goes darker.
• Finishing time. Troweling too early raises the surface water content and lightens the color; hard troweling lowers it and darkens. Since a crew works across a slab in sequence, the far end is finished at a different maturity from the near end.
• Curing. Plastic sheeting is the classic culprit: where it touches the slab and where it does not, hydration differs, and the slab dries mottled in the shape of the wrinkles.
• Mixing time. Under-mixed pigment streaks. At least 100 revolutions or 10 minutes is the guidance.
• Efflorescence. The one people never see coming, covered below.

The efflorescence number worth remembering. Euclid Chemical puts it at 0.2 ounces of calcium carbonate per square yard to cause a significant shift in color. A fifth of an ounce spread over a square yard is an invisibly thin film, and it is enough to change the color you see. On a colored slab, where expectations are higher, it is far more noticeable than on gray.

Tellingly, the industry's own advice is not to match better but to camouflage: NRMCA suggests "applying a texture or other pattern" to reduce the perception of color variation between loads. Nobody claims batch-to-batch matching is achievable. Pour a test slab, accept variation as part of the material, and choose a finish that hides it.