DIY Acid Stain for Concrete

Transform Plain Concrete Into Rich, Variegated Color

Kemiko Stone Tone Acid Stain helps turn ordinary concrete into a distinctive finished surface with the character of aged stone, marble, or natural texture. It is designed for homeowners and contractors who want a durable decorative finish for interior and exterior concrete surfaces. Kemiko also highlights that results are permanent, unique to each slab, and dependent on the concrete itself.

Is This Project Right for you?

Acid staining works best when you want a natural, mottled look rather than a flat painted color. Because concrete varies from slab to slab, each floor develops its own character. Kemiko recommends testing a small, hidden area first to confirm that the concrete will react properly and to help you preview the final appearance. A new slab should cure for about 4 to 6 weeks before staining.

Before You Start

Important Safety Notes

Kemiko states that the stain contains acid. Wear:

  • Safety goggles
  • Rubber gloves
  • Rubber apron
  • A properly fitted approved respirator when exposure to vapor or mist is likely

Surface Preparation

he surface must be clean and free of:

  • Paint
  • Wax
  • Grease
  • Dirt
  • Surface contaminants

Do not acid wash before applying Kemiko stain. Kemiko specifically recommends cleaning instead of acid washing, and notes that Neutra-Clean is their recommended cleaner for prep and residue removal.

Basic Tools & Materials

For a typical DIY application, Kemiko recommends:

  • Cleaner such as Neutra-Clean
  • Stiff bristle scrub brushes
  • Wet vacuum, mop, or squeegee for cleanup
  • Painter’s tape and painter’s paper to protect walls
  • An all-plastic garden pump sprayer with no metal parts
  • Kemiko Acid Stain
  • Water for dilution
  • Your chosen finish system based on interior or exterior use

Step by Step

Step 1: Clean the Concrete

Wash the surface thoroughly so it is free of contaminants. Kemiko recommends avoiding heavy alkali cleaners and says not to acid wash before staining. After cleaning, let the slab dry completely. Protect nearby walls with painter’s tape and painter’s paper, and avoid letting stain touch wood or metal.

Step 2: Apply the First Coat of Stain

Kemiko says the stain is generally mixed 50% stain and 50% water. Put the water in the sprayer first, then add the stain. Shake the stain container well before use.

Spray randomly from about 18 inches above the floor. Avoid rigid back-and-forth patterns. A finer spray creates a more natural appearance. Apply enough material to leave the surface moist, but avoid puddles, since puddled areas may become darker. Kemiko notes that more volume generally creates deeper color. Then allow the floor to dry completely.

Step 3: Apply the Second Coat

Apply the second coat the same way as the first. Let it dry completely again. Kemiko notes that darker tones usually become more noticeable after the second application.

Step 4: Remove the Residue

After the floor is completely dry, scrub off the residue with a scrub brush and Neutra-Clean and/or water. Remove the residue-water mixture with a wet vacuum, mop, or squeegee. Kemiko suggests testing cleanup by wiping with a white towel. If color comes off on the towel, clean again. Then allow the slab to dry completely before applying any protection coat.

Step 5: Choose Your Finish Path

Kemiko presents DIY finishing as a “path” based on where the concrete is located and the look you want.

Interior Finish Options

For interior floors, Kemiko lists finish paths such as:

  • Rich luster: Buff-On Wax
  • Glossy: Stone Tone Sealer II + Easy Shine Wax
  • Matte or satin: Stone Tone Sealer II + Easy Shine Wax
  • Commercial: Sta-Crete Epoxy

Exterior Finish Options

For exterior concrete, Kemiko lists options such as:

  • Flat rock: stain and clean only
  • Natural: Repels
  • Glossy: Stone Tone Sealer II
  • Matte or satin: Stone Tone Sealer II
  • Commercial: Sta-Crete Urethane

Sealer and Finish Guidance

Kemiko says Stone Tone Sealer II should only be applied after the slab is dry, generally after at least 24 hours, depending on temperature and humidity. They state that two coats are almost always needed, with more coats sometimes required on porous surfaces. Dry times listed are about:

  • 1 hour before recoat
  • 4 hours before foot traffic
  • 24 hours before heavy traffic
  • 48 to 72 hours for full cure

For exterior protection, Kemiko says Repels is a 0 VOC silane/siloxane emulsion. It should be applied only to a dry, clean surface, and not if rain is expected within 24 hours.

Kemiko also advises that sprayers usually produce the best sealer results and warns that rollers can create texture, leave too much material, or interfere with bond quality. They emphasize that the most common mistake with sealers is applying too much volume at once.

Interior Wax Option

For interior projects using sealer, Kemiko recommends Easy Shine Mop-On Wax as a finish coat to reduce scratching. They state it dries in about 20 to 30 minutes and should not be applied over Buff-On Wax. They also state plainly: never put sealer over wax.

Color Options

Kemiko’s color chart shows classic earth tones and specialty shades including Cola, Malay Tan, Vintage Umber, Walnut, Golden Wheat, Black, Garden Gold, English Red, Green Lawn, and Aqua Blue. The chart also notes that the colors shown are approximate and actual results will vary.

Ongoing Maintenance

Kemiko says decorative concrete floors need regular maintenance, but are easy to care for when properly finished. Their recommendations include:

  • Damp mop with water
  • Use only very mild detergent when needed
  • Avoid ammonia or bleach-based cleaners
  • Add felt pads to furniture
  • Lift furniture instead of dragging it when possible

Frequently Asked Questions

How long should new concrete cure before staining?

Kemiko recommends allowing a new concrete slab to cure for 4 to 6 weeks before staining.

Should I test the stain before doing the whole project?

Yes. Kemiko recommends testing a small, out-of-the-way area first. If the stain does not react the way it should, surface contamination is often the cause.

Do I need to acid wash before applying Kemiko stain?

No. Kemiko specifically says do not acid wash before applying the stain, and also advises against using heavy alkali cleaners.

What is the usual stain mixture?

Kemiko says the stain is generally mixed 50/50 with water. They also recommend putting the water in the sprayer first, then adding the stain.

What kind of sprayer should I use?

Kemiko recommends using an all-plastic garden-type pump-up sprayer with no metal parts so you can control the volume more easily during application.

How many coats of stain should I apply?

Kemiko’s application instructions describe applying a first application, letting it dry completely, and then applying a second application using the same method.

When do I remove the residue?

Kemiko says to wait until the floor has dried completely after the final stain application, then scrub off the residue and clean the surface. If color still transfers to a white towel after wiping, clean it again.

How do I choose the right finish?

Kemiko explains that most projects follow the same path through preparation, stain, and residue removal. The main choice comes at the protection stage, where the finish depends on the use of the surface and the appearance you want.

What protection options are used for interior projects?

Kemiko lists these common interior finish paths:

  • Rich Luster: Buff-On Wax
  • Glossy: Stone Tone Sealer II + Easy Shine Wax
  • Matte or Satin: Stone Tone Sealer II + Easy Shine Wax
  • Commercial: Sta-Crete Epoxy

What protection options are used for exterior projects?

Kemiko lists these common exterior finish paths:

  • Natural: Repels
  • Glossy: Stone Tone Sealer II
  • Matte or Satin: Stone Tone Sealer II
  • Commercial: Sta-Crete Urethane

Can I put sealer over wax?

No. Kemiko gives a very clear warning: never put sealer over wax.

How do I maintain a stained concrete floor?

Kemiko recommends cleaning finished concrete floors with a damp mop and water only, or a very mild detergent if needed. They also say not to use heavy cleaners such as ammonia or bleach, and to use felt pads under moveable furniture.

Is scoring required?

No. Scoring is optional. Kemiko explains that it can be used to create the look of stone or tile, but it is not required for a successful stain project.