Concrete floors are naturally gray in appearance. There are many laminates, paints and stains available commercially that are easy to use for added color, but they may be costly and dig a little too deeply into your remodeling budget. If brown is a color you would like to try, you can simply create your own brown stain mixture with coffee grounds and inexpensive iron sulfate.
Clean the floor using soapy water and a mop. Once the floor is dry to the touch, it is ready to be stained.
Mix iron sulfate, water and coffee grounds in a five-gallon bucket. Used alone, iron sulfate produces a rusty orange hue, but adding coffee grounds to the mixture will produce varying levels of brown stain. According to appropedia.org, the proper mixture is two pounds of iron sulfate to one or two cups of coffee grounds, and one gallon of water. Do not let the mixture sit for more than a few minutes, since the iron sulfate will begin to collect at the bottom of the bucket.
Prepare a second five-gallon bucket that will be used to strain the iron sulfate particles and coffee grounds from your homemade stain. Place a section of cheesecloth over the top of this bucket, securely taping it in place with duct tape.
Strain your mixture through the cheesecloth. If you have anyone to help with this project, have that person hold the cheesecloth in place while you pour, just in case the tape doesn't hold well. In your second bucket, you now have a nice stain with no lumps or chunks.
Apply the stain to the concrete using a rag or any piece of fabric you don't mind throwing away. A mop can be used, but tends to leave more streaks or unevenly colored areas. The stain color will not appear immediately. After 10 minutes, the color will become more apparent.
Allow the floor to dry for a day or two, then vacuum any iron sulfate dust that has accumulated on the surface. To avoid inhalation of iron sulfate particles, wear a face mask while performing this task.