Direct Colors Acid Stains for concrete are designed to enhance the appearance of concrete and other cement-based surface materials. Reactive stains produce unusual and permanent color effects in concrete, self-leveling topping systems, gunite, cement plaster, stucco, shotcrete, natural stone marble, cultured stone, limestone and other surfaces.
Each concrete acid stain creates uneven color effects that simulate the natural shadings and aged appearance of stone or masonry. The color effect is unique to each stained surface and cannot be duplicated with other materials.
Application Tool: Pump sprayer, sponge or foam brush
Dry Time: Up to 12 hours depending on desired shade
Cleanup: Organic cleaner and degreaser
Coverage: 200 sq. ft. per gallon
What is Acid Concrete Stain?
Most acid stains in the market are a mixture of mostly water, hydrochloric acid and soluble metallic salts. Direct Colors Concrete Acid Stains are composed of a unique concentrated formulation of blended metallic salts in an acidic water-based solution.
These metallic salts penetrate and react with the minerals in the concrete to deposit the colors into the concrete pores.
Each color is composed of a complex proprietary formulation that contains no pigments or resins. When highlighted with the proper sealer, this effect provides a natural and attractive glow that will not chip off.
How much acid stain do I need?
Direct Colors has taken the guess work out of your next project! but if you must know, you need about one quart of acid stain per every 50 square feet of surface.
We always recommend applying two coats but if you are gearing toward the multi-color acid stain approach then the single coat of coverage ratio will work for each color.
If you are applying the recommended 2 coats, use our Coverage Calculator. This tool will not only tell you how much acid stain you will need but also how much sealer and floor wax you will require to complete a project.
Direct Colors Concrete Acid Stains are available in 1 qt (0.95 L), 1 gal (3.8 L), 5 gal (18.9 L) and 55 gal (208 L) containers.
Concrete Stain Colors
Acid stain is a translucent product and the overall effect of the stain system leave an element of unpredictability to the final appearance of the applied stain. For acid stain color stunning color combination ideas read Direct Colors Concrete Acid Stain Color Guide.
Testing small areas or samples prior to starting a project is highly recommended since the final color may differ significantly from what is shown on the chart due to a number of factors, including, but not limited to the age of the existing slab, mix design, finishing techniques, concrete base colors and surface permeability.
Before Acid Staining: Know Your Concrete
Prior to staining, a slab must meet the following criteria:
- Concrete must be free of debris, dirt and oils, paint, dry wall mud, adhesive, sealers, stains of any kind or similar materials. Acid stain cannot react properly with the concrete if these conditions are present.
- Concrete should not have been treated with a waterproofing agent, cleaned with muriatic acid or a heavy trisodium phosphate (TSP) solution. The acid stain reaction cannot occur on surfaces treated with these products.
- Newly poured concrete slabs and countertops should include less than 10% fly ash to insure a good chemical reaction with the acid stain. Check with your ready mix company or read the countertop mix MSDS for concrete additive information.
- Newly poured concrete can be acid stained anytime from 20-28 days after the pour or once the concrete has achieved a uniform light gray color.
- For older, excessively power-washed, or mechanically-profiled concrete may not react with acid stains.
- Concrete acid stain does not stain rocks, sand or aggregate.
- Exposed aggregate or otherwise depleted Portland cement may cause the acid stain to take irregularly, react weakly or produce a color inconsistent with the acid stain color chart
- Slick, machine-troweled concrete requires mechanical or chemical etching for a complete acid stain reaction to occur.
- If water beads on the surface or dark gray areas caused by excessive troweling are visible caused by excessively troweling, Hard Troweled Floor Prep should be sprayed on the concrete or the surface should be sanded using an 80-grit sanding pad prior to application.
- Concrete poured with excessive water in the mix can create a thin, unstable layer of concrete on the slab surface.
- To test for instability, press the tip of nail into the concrete. If breaking or damage of any kind occurs, the slab must be profiled with a concrete grinder or a high-speed buffer using a 60-80 grit sanding disc before staining.
Important: NOTHING takes the place of pre-application testing, particularly if you do not know the history of your slab. Always prepare a test area on the slab intended for staining prior to beginning a project.
1. Preparating the Concrete Surface
Surface Preparation is the most important step in the acid staining process. For details click here
- Concrete Acid Stain is not an over coat, but is an opaque, semi-transparent, penetrating color that permanently changes the appearance of the concrete.
- Areas where debris remains on the surface will likely not accept the stain leaving color imperfections on the floor, particularly mastic, dry wall mud and paint. Use Bean-E-Doo, for the removal of adhesives.
- Apply Soy Gel Professional Paint Stripper to remove epoxy, sealers, varnish or paint.
- Use Xylene to remove solvent-based sealers and clean up sprayers or tools.
- Use Soy Gel Professional Paint Stripper or a similar product to strip water-based sealers from concrete.
- If you desire a more even finish, consider overlay resurfacing especially on slabs with exposed aggregate or surfaces so soiled that cleaning would prove too difficult.
- For best acid stain results on indoor slabs, sand the floor with a 150-200 grit pad applied with a floor buffer to properly prepare the surface for staining. Sanding will remove most if not all debris from the surface and correctly profile the concrete for staining.
2. Applying the Acid Stain
Safety First! Remember to use goggles, gloves and a dust mask while working with concrete acid stain.
- After cleaning concrete, you do not have to wait for concrete to dry to start the acid stain application.
- The appearance of the finished product is very much influenced by the manner in which the acid stain is applied.
- We recommend spraying the stain on the surface using an all-plastic pump sprayer.
- For smaller spaces a plastic spray bottle can be used.
- If a darker, more even one is desired, brush the acid stain into the surface using consistent circular strokes.
- If using a brush, spray on a second coat to eliminate any brush strokes on the surface unless that is the desired finish.
- For a more diffuse look, spray the stain onto the surface without brushing.
- A multi-colored effect with distinct areas of color, begin with your lightest color as a base coat.
- Base coat colors can either be a light acid stain color such as Azure Blue, Malayan Buff or one of the darker stains cut with water.
- Apply one heavy coat of your base color and immediately apply accent coats while the stain is still wet to encourage a more natural appearance on the slab.
- Continue to apply the lighter to darker colored accents until satisfied with the results.
- If walking on wet acid stain, wear acid resistant spiked shoes, golf shoes or similar cleats to avoid leaving foot impressions on the floor.
To learn more about "Marbling Effect"
technique with acid stains click here
- For a veined appearance, spray your secondary or “veining” color on the surface first.
- While still wet, feather the primary color into and around the secondary color allowing it to flow together at the edges.
- Be careful not to cover your secondary color completely especially if it is a lighter shade.
For more details on "Veining Technique" click here
- No two finished floors are exactly same as acid staining is an artistic process.
- Always complete small test patches on your surface or prepare sample boards to practice with the sprayer and determine which look you prefer.
- Each of our acid stain colors can be cut with water to produce an array of different colors and shades.
- Keep in mind if the water content is too high, the chemical reaction between the stain and the concrete will be significantly reduced and may not be strong enough to produce the desired color, especially on older slabs.
- We do not recommend cutting our acid stains by more than 4 parts water to 1 part acid stain unless you are very experienced with this product.
- Some colors vary more than others when increasing the water content and many factors determine how dark the final stain color will be such as age of concrete, cement content and weathering.
- As the acid stain dries, a chalky residue will likely form on the surface of the concrete and is a normal part of the staining process.
- Each stain has different activation times to fully color the concrete, generally from four to eight hours. However, the stains can be left on for longer if a darker color is desired.
For a complete list of Acid Stain Color Activation Times click here
Hot, dry conditions can cause acid stain to prematurely dry before properly reacting with the concrete. For best results, slightly dampen the surface before applying acid stain to outdoor concrete. Sealers should not be applied to concrete over 90 F. For outdoor projects, apply sealers either late in the evening or early in the morning when concrete temperatures are at their lowest.
Check your stain’s activation time before beginning the job. Stains can be left on the surface for longer but not less than the activation time.
- If you are working on a concrete countertop project or attempting to stain separate rooms the same color, use a timer to insure equivalent activation times for each countertop section or room.
- Remember to spray a second coat of stain over the dried residue of the first coat to assure complete coverage.
- Do not walk on wet residue.
- If you must walk on the processing surface use acid stain resistant spiked shoes to prevent marks or shoe impressions on the surface. Golf shoes, football cleats or plastic bags over sock feet can also be used.
- Avocado, Azure Blue, Sea Grass and Shifting Sand concrete acid stain are not recommended for outdoor use.
Keep in mind that all concrete surfaces are not alike. Although acid staining overlaid surfaces generally produces similar results to that of new concrete slabs, variation between products can occur. To assure the desired results, always prepare a small test area prior to beginning any acid stain project.
How Long Does Acid Stain Take To Dry?
Different stains require varying amounts of time to activate and fully color the concrete, generally from 2 – 8 hours. Use our Acid Stain Color Activation Times Chart
for details. Be sure to check the acid stain color activation time before starting a project to ensure full surface coloring. For the most color from a given stain, spray another coat over the dried residue.
3. Neutralizing and Removing Residue
Once the residue has dried and the stain has been given at least the recommended minimum time to react, the surface should be neutralized and all debris or excess stain removed in the following manner:
- Prepare a solution using baking soda at a ratio of 1-2 tablespoons of soda per gallon of water.
- Thoroughly spread the solution across the slab, scrubbing with a nylon scrub brush where needed to remove residue.
- A shop vacuum can also be used for indoor projects. For applications including Penetrating Hardener/Sealer, consider repeating this step to be absolutely certain all concrete acid stain has been neutralized before cleaning.
- Wash the surface carefully using clean water until nothing but clear water is visible.
- All residue and excess color must be removed from the floor BEFORE leaving to dry.
- For stubborn residue or porous surfaces, use a floor soap or organic degreaser to aid in the removal.
- The clean, wet surface will be the approximate color of the final sealed surface.
- Leave to dry.
- After the surface has completely dried, the floor should be ready to seal.
4. Sealing the Color
After the surface has been neutralized, cleaned and has thoroughly dried, the acid stained floor must be sealed with an appropriate concrete sealer. See how-to guide specific to your sealer purchase.
DO NOT apply masking or duct-tape to a stained and sealed surface. The tape will adhere to the sealer and damage the acid stain finish.
5. Waxing Indoor Surfaces
- Applying Concrete Floor Wax and Polish to your surface is a critical final step in maintaining interior decorative concrete.
- Wax protects the finished surface but does not replace the need for sealer on your floor.
- While sealer penetrates into the pores of your concrete and maintains your floor’s color, wax is a topical coat designed to serve as a barrier between daily wear and tear and your floor’s sealed surface.
- If properly waxed and maintained, you’ll never need to seal again! Remember, floor polish is intended for interior applications only and should not be applied outdoors.
- *Allow for 48-72 hours dry time for floors sealed with solvent based sealers before applying Residential or Commercial Wax.
- Before waxing thoroughly clean all dirt and debris from the surface using warm soapy water or water mixed with a light organic degreaser.
- Do not use harsh chemicals such as xylene, lacquer thinner, adhesive remover or similar products. These chemicals will remove your sealer and ruin the finish on your decorative concrete.
- First mop the floor with the cleaning solution then mop again using water only. Finally, leave the floor to dry making certain all residue has been removed from the floor.
- After the surface has dried, apply either the residential or commercial wax with either a sponge mop with wringer attachment, Floor Coater or Trim Pad. Pour the floor polish into a paint tray and use the ridges to purge the applicator of excess polish before applying.
- The thinner the coat, the stronger each layer of floor polish will be.
- For the first application, apply 2-3 thin coats floor polish allowing each coat to dry completely before applying the next.
- To limit the possibility of streaking, apply the first coat East to West and the second coat North to South.
- Before allowing traffic on the floor, test the wax by applying pressure to the surface with your fingernail.
- If the surface dents the wax will require more time to dry. Select commercial wax over residential wax if large dogs will routinely be on the floors.
- Buffing in this instance would be optional.
- Depending traffic conditions, the floor should be waxed approximately every 3-8 months.
- Before reapplying, walk the surface of the floor to determine if spot waxing will suffice.
- Always clean the floor thoroughly before application.
- Cold Temperature Warning: DO NOT apply water-based concrete sealers or floor waxes when surface temperatures are below 65°F.
- Turn on the central heat and air etc. to 75°F before applying to raise the floor temperature.
- Lay a flat thermometer covered with a towel on the floor for 5-10 mins or use an infrared thermometer to confirm floor temperature.
- All heating sources and overhead fans must be turned off during application.
- In-floor heating should be set at 60-65 degrees before and turned off during the application process.
- Fans and heat can be turned on after application to aid with drying.
- Do not allow to freeze.
Direct Colors Concrete Acid Stains are available in 10 standard colors.
Use our Acid Stain Sample Trial Kit
to test colors and our Design by Color photo gallery for color combination and technique ideas.
Click/Tap each question to hide/show the answers.
What happens if you stain concrete before it cures?
Any stain applied to concrete before it has fully cured for at least 28 days is likely to experience unintended color effects.
Think about it, acid stain is a water-based liquid containing reactive minerals. The acid stain seeps into the pores of the concrete and a chemical reaction occurs between the acid stain and the available lime within the surface. If the concrete has not fully cured; the concrete will be evaporating more water into the stain while it reacts, so the color will most likely look watered down or not take at all!
Do I have to let concrete dry after cleaning prior to applying acid stain?
No, the concrete can be damped prior to stain application. However, you should not have puddles of water before staining as the water will dilute the stain.
Important: Shades depicted in “Color Chart” may vary from actual results. Concrete Acid Stain reacts with specific minerals in concrete. Results may vary from “Color Chart,” and from project to project.