Naturally variegated. Uniquely yours.
RAC Reactive Acid Concrete Stain
Create rich, permanent color that reacts with the minerals in concrete. RAC produces natural movement and variation that cannot be duplicated by paint or a topical coating.
Interior + exteriorNaturally variegatedPermanent chemical reactionEvery slab is uniqueNeutralizer requiredTopical sealer required
Shop the RAC system
Acid stain, samples, neutralizer, extender, and sprayers
Naturally one of a kind
RAC reacts with the concrete—it does not cover it.
Reactive Acid Chemical Stain produces permanent, translucent color through a chemical reaction with minerals in the slab. The finished color and movement are influenced by the concrete itself.
AgeCompositionTexturePorosityPreparationApplication
The complete RAC process
React, neutralize, clean, dry, and seal.
Do not judge RAC by its appearance before the entire process—including sealing—is complete.
Prepare
Remove dirt, grease, oil, wax, paint, adhesives, curing compounds, sealers, and other contaminants. Water should absorb instead of bead.
Test
Test on the actual slab and carry the sample through neutralizing, cleaning, complete drying, and sealing.
Apply RAC
Apply evenly with acid-resistant equipment. Avoid unwanted overlap patterns, footprints, and puddles.
Let It React
Allow the chemical reaction to develop according to the current product instructions and site conditions.
Neutralize
CR-585 Surface Neutralizer is required after RAC. Apply it thoroughly across the stained surface.
Rinse + Clean
Scrub, remove dirty water, and repeat until no loose powdery or chalky residue remains.
Dry Completely
Do not trap moisture beneath the sealer. Moisture can cause cloudiness, blushing, or adhesion problems.
Seal
Protect and reveal the finished color with a compatible topical sealer selected for the project location.
Required after acid stain
Neutralizing is not optional.
After RAC has reacted, use CR-585 Surface Neutralizer, scrub thoroughly, rinse, and remove the dirty water. Repeat cleaning as needed until loose reaction residue is gone, then allow the slab to dry completely.
Create lighter RAC color
Use RAC Color Extender—not water.
Color Extender reduces RAC color strength while maintaining the balance needed for the acid-stain reaction. Mix each ratio with 1 part RAC.
1 part RAC
10% reduction
1 part RAC
20% reduction
1 part RAC
40% reduction
1 part RAC
80% reduction
Important: Do not dilute RAC with water to lighten the color. Use CR-645 RAC Color Extender and test the complete sealed system before beginning the project.
Explore RAC colors
Choose a direction. Let the slab create the variation.
Color charts are a starting point, not a guaranteed result. Concrete chemistry and surface conditions can make the same RAC color develop differently from one slab—or one area—to another.
Set the right expectation
Your test is not finished until it is sealed.
RAC can look dull, chalky, or muted before loose residue is removed and the surface is sealed. A meaningful test follows every project step on the actual concrete.
- Apply and react
- Neutralize
- Scrub and rinse
- Dry completely
- Apply the chosen sealer
Build the complete system
Planning an interior or exterior project?
Use the project guides to calculate preparation products, RAC stain, neutralizer, compatible sealer, and application tools.
RAC FAQs
Before you begin
Review the current product instructions and technical data sheet before preparing, staining, neutralizing, or sealing the concrete.
How does RAC color concrete?
RAC reacts chemically with minerals in the concrete to create translucent, naturally mottled color. It does not form an opaque paint-like film.
Will my finished floor match the color chart?
Not exactly. Slab age, composition, texture, porosity, preparation, and application all influence the reaction. Use the chart to choose a direction, then test on the actual concrete.
How should the concrete be prepared?
The surface must be clean and porous. Remove grease, oil, wax, paint, adhesives, sealers, curing compounds, and other contaminants. Water should absorb into the slab rather than bead.
Is CR-585 Surface Neutralizer required?
Yes. CR-585 must be used after RAC. Neutralize the entire stained surface, scrub thoroughly, rinse, and remove the dirty water.
How do I know the reaction residue is removed?
Continue scrubbing, rinsing, and removing dirty water until no loose powdery or chalky residue remains. Residue left behind can interfere with the sealer.
Can I apply a second coat?
A second application may increase color development where reactive minerals remain, but results vary by slab. Evaluate only after following the current product directions and test first.
How can I make RAC lighter?
Use CR-645 RAC Color Extender at its published ratios. Do not simply dilute RAC with water, because the extender is designed to maintain the balance needed for vivid acid-stain color.
Why does RAC look dull before sealing?
Uncleaned or unsealed RAC often looks muted or chalky. The meaningful color evaluation happens after neutralizing, removing residue, drying completely, and applying the intended sealer.
How long should the concrete dry?
Allow it to dry completely according to current product and sealer instructions, as well as site conditions. Trapped moisture can cause cloudiness, blushing, or adhesion issues.
Does RAC require a sealer?
Yes. RAC requires a compatible topical sealer to protect the surface and reveal the finished appearance. Choose the sealer for the project location and performance needs.
Can RAC be used outdoors?
Yes, RAC may be used on suitable interior and exterior concrete. Exterior projects require an exterior-compatible sealer and maintenance appropriate to exposure and traffic.