How to Stain a Concrete Floor

DIY Acid Stain

Concrete floors, while durable, can leave much to be desired when it comes to their appearance and their ability to tie in with the rest of your home’s decor. Fortunately, plain concrete floors can be customized by adding an acid stain which can darken and even marbleize the surface to meet your decorating preferences. Applying an acid stain to a concrete floor can is relatively simple and can be easily accomplished with the right supplies.

Things You’ll Need:

Concrete acid stain

2 gallon spray pump



Standard paint roller

Wet/dry vacuum cleaner

push broom with no metal components

Five gallon bucket or container

Painter’s tape

Roll of postal parchment paper

Step One:

Protect your walls and baseboards to prevent acid damage and discoloration. To do this, simply use your blue painter’s tape to completely cover the baseboards in the room you will be staining. Once your baseboards are covered, use your postal parchment and your painters tape to cover the walls. Postal paper is relatively wide so one piece for each wall for the area over the baseboard should cover it. The wall does not need to be completely covered as this process is simply to protect the walls from splashing acid which can damage your paint.

Step Two:

Remove any excess dirt from the floor surface before beginning the staining process. Using a push broom, sweep any dirt and debris from the floor, starting at the corners and working towards the middle. Once the dirt is piled up in the center of the room, use your wet/dry vacuum to remove it from the area. Debris left on the floor can cause odd effects in your stain so be sure to remove as much of the dirt as possible.

Step Three:

Prepare your stain mix for use. The stain should be mixed in a ratio of one part stain to four parts water and the amount you premix will directly depend on the size of the room to be stained. To mix the solution, fill your five gallon bucket with water before measuring and adding the appropriate amount of stain solution. Acid stain should always be added to the water last because it will help prevent splashing and will also help you control the darkness of the stain you are mixing.

Step Four:

Apply the acid stain mixture to the concrete floor using your pump sprayer. Carefully lift your five gallon bucket and fill the tank on your pump sprayer to ready it for use. There are a variety of sprayers that will work for this purpose but make sure to use one that has only plastic parts as the hydrochloric acid will react violently with metal. Begin applying the stain by spraying the entire floor in a circular fashion. Spray each area of the floor until it is thoroughly wet but avoid over spraying and leaving puddles as this will cause odd etching and patterns in the stain. Once the entire floor has been sprayed with the stain, allow the floor to sit untouched to dry for an hour before repeating the spraying process for a second coat.

Step Five:

Once your second coat (or third depending on preference) has dried, you will need to neutralize the hydrochloric acid in the stain so that it is no longer potent and harmful. To do this, mix a solution of one part ammonia to four parts water and pour into the tank of your spray pump. Spray the solution and thoroughly soak the entire concrete floor but avoid over-spraying and creating puddles. Allow a few hours for the solution to dry on the floor.

Step Six:

Clean the floor to prepare the concrete for sealing solution. Once your ammonia spray has dried, use a clean mop and your wet/dry vacuum to remove any excess water on the floor. Avoid using used mops and brooms because they tend to spread dirt and water instead of picking it up and absorbing it.

Step Seven:

Apply a clear gloss concrete sealing solution to protect the stain from wear. Concrete seal comes in several different varieties and can be purchased easily at your local hardware store. Follow the mixing instructions on the package and then, using a standard paint roller, roll on an even coat of sealant to the entire stained area. In most cases you will get the best result with two coats of sealant, so allow a few hours for drying in between the application of the first and second coats. Once the second coat has been rolled, leave the room unattended for an entire day before removing the protective wall and baseboard coverings. At this time the room should be fully functional again and you can begin bringing furniture back in and resume activities as normal.


-Concrete acid stain contains hydrochloric acid which is highly dangerous to the skin. Be sure to wear adequate protective clothing and equipment while working with this chemical.

-The chemicals used in this process all put off fumes that can be potentially hazardous when inhaled. This project should be completed in a well ventilated area to avoid accidental poisoning.