facebook
twitter
pinterest
linkedin

Acid Stain for Concrete Floors: Both Indoors and Outdoors

Acid stain is a low-cost flooring option for concrete floors. Along with customizable color, acid staining and sealing ensures durability and added life to any indoor or outdoor concrete surface. 

Azure blue, desert, amber and shifting sand EverStain acid stained concrete floors
Azure blue, desert amber and shifting sand EverStain acid stained concrete floors

How Much Do Acid Stained Concrete Floors Cost?

The cost of acid stained floors begins at $0.47 per square foot, which is far less than tile, carpet, marble, or other common flooring options. Depending on design and surface conditions, costs can rise as high as $10.00 per square foot!

Yet, unlike hardwood, tile, and carpet, which require professional installation, homeowners can lower costs by acid staining concrete flooring themselves.

Do it yourself
Affordable do-it-yourself project

What is acid stain?

Acid stain is a translucent, penetrating stain that slightly etches and permanently changes the color of concrete by reacting chemically with the hydrated lime in the concrete.

When deciding on a look for your new flooring project, it’s important to understand that acid stain is not an overcoat like paint.

If your concrete floor has drywall, mud, paint, wood stains, tile adhesives, carpet adhesives, grease, pet stains, etc. either from construction or years of use, preparation of the concrete surface is crucial to achieving ideal results.

Carpet adhesive on concrete floor
Make sure to remove all carpet adhesive

Acid Stained Concrete Floors: How to Guide


Step 1: Prepare Surface

Surface preparation is the most important step of the acid staining process. The concrete must be free of adhesives, dirt, paint, oils, drywall, mud, sealer, and stain. Acid stain cannot react with the concrete if any of these contaminants are present.

Concrete Floors NOT Ready For Staining

Concrete floor with paint stains
Floors with paint stains will NOT absorb acid stain.
Concrete floors with carpet glue
Floors with carpet glue will NOT absorb acid stain.
Water on sealed concrete surface after one hour
If water doesn't absorb after five minutes, it's probably been sealed.
Basement floor with old stains, spray paint and overspray on it
Basement floor with old stains, spray paint & overspray on it.

Step 2: Clean the Concrete

Clean the floor with a light concrete cleaner and degreaser solution. Thoroughly scrub and rinse all residues from the surface. Use a shop vac to vacuum up the rinse water and speed up the drying time.

If your concrete floors are machine troweled, prepare the surface by etching it with CitrusEtch™ concrete etcher. This process will add texture to smooth concrete floors for increased stain absorption.

Concrete Floors Ready For Staining

Clean and ready for acid stain application
Clean and ready for acid stain application

Step 3: Apply the Acid Stain

Apply acid stain using a pump up sprayer or an industrial strength plastic sprayer. Safety while applying colorant is important! Remember to use long sleeves, pants, goggles, and gloves while working with the acid stain.

Diffusing acid stains on concrete floor
Diffusing azure blue, desert amber and shifting sand by alternating spray bottle colors

Learn How to Acid Stain Interior Concrete Floors

The stain color finish is highly influenced on how you apply the acid stain. Here are a few tips on how to achieve the ideal finished product:

  • For an even-toned color, spray the acid stain in a circular motion.
  • For a dark toned color, use a brush to work the acid stain into the surface using consistent circular strokes. Then spray on a second coat to eliminate any brush strokes on the surface.
Blending in acid stains
  • For a diffused look, spray the stain onto the surface without brushing.
  • For a marbling effect, apply one heavy coat of your base color and immediately apply scattered accent coats while the acid stain base is still wet. Continue to apply lighter, then darker-colored accents until you are satisfied with the results.
Acid stained concrete floor

Remember to wear acid resistant spiked shoes to avoid leaving foot impressions on the floor.

Step 4: Let Acid Stain Work

As the acid stain dries and processes, a residue of alkali and minerals forms on the surface of the concrete. This is completely normal and is part of the reaction process. Each stain has different activation times to fully color the concrete, generally from 4 to 8 hours. Acid stain can be left on the surface longer if desired.

Allow the acid stains to work
Allow the acid stains to work

Step 5: Neutralize The Acid Stained Concrete Floor

Neutralize and clean acid stain residue
Neutralize and clean acid stain residue
  1. Prepare baking soda and water solution using 1-2 tablespoons of baking soda per gallon of water.
  2. Spray or pour the soda and water solution on every inch of the floor.
  3. Move the solution around the floor using a squeegee.
  4. Scrub with a soft nylon bristle scrub brush where needed to remove residue.
  5. Wash the surface carefully using clean water until nothing but clear water is visible.
  6. Remove all residue and excess color from the concrete before leaving it to dry.
  7. For stubborn residue or porous surfaces, use an organic degreaser to aid in the removal. The clean, wet surface will be the approximate color of the final sealed surface.
  8. Leave to dry.
  9. After the surface has completely dried, the floor should be ready to seal.

Neutralizing your acid stain is an absolutely essential step in a successful concrete acid stain application. Read more about the importance of this step.

Step 6: Seal the Acid Stained Concrete

  • For sealing indoor concrete floors, Direct Colors recommends our AcquaSeal water based acrylic sealer. This sealer is low VOC which makes it a safer choice for interior application.
Azure blue, desert, amber and shifting sand EverStain acid stained concrete floors
Azure blue, desert amber and shifting sand EverStain acid stained concrete floors
Seagrass EverStain Swatch
EverStain Seagrass
Desert Amber EverStain Acid Stain
EverStain™ Desert Amber
Shifting Sand EverStain Swatch
EverStain™ Shifting Sand
AcquaSeal Satin
AcquaSeal™ Satin
ProWax™ Polish Satin
ProWax™ Polish Satin
  • For sealing outdoor concrete floors, Direct Colors recommends our EasySeal solvent-based acrylic sealer. This particular sealer is super easy to apply, dries fast, and makes the color of outdoor concrete projects really pop.
Seal Exterior Acid Stained Surface with a Solvent-Based Sealer
Seal exterior acid stained surface with a solvent based sealer.

Step 7: Apply Liquid Concrete Wax (Interior Floors Only)

Acid stained log cabin concrete floors
Malayan buff, seagrass and black EverStain acid stains sealed with AcquaSeal and ProWax Polish gloss
  • Soak trim pad applicator in warm water.
  • Wring out excess water from the applicator.
  • Pour concrete wax into a paint tray.
  • Saturate trim pad with concrete wax solution.
  • Press out excess wax.
  • Apply a thin milky coat across the floor surface. The product will appear milky in application but clear as it dries.
  • Smooth out any foaming from the concrete surface.

Use ProWax Polish to protect the colored floor coating from daily wear and tear. Regular waxing is important in high-traffic spaces like hair salons where high traffic and repetitive motion around hair stations are likely.

Learn How to Acid Stain Outdoor Concrete