Staining an existing concrete slab that has been previously painted is a task that will require a bit of preparation before the stain can be applied. After the stain has been protected with an epoxy sealer it will be more durable than stone and tile. The stain will also hide unsightly blemishes, and marks in the concrete. There are a wide variety of options and designs when staining concrete. The resulting look can be made to design patterns, or even faux finishes to look like granite, stone, or even wood.
Wash the concrete with a power washer if available. These may be rented at local home improvement stores. Most of the paint on the concrete will be removed. Scrape away small remaining amounts with a wire brush. If larger amounts of paint are still remaining apply a generous amount of paint stripper. Leave the stripper sit for about an hour. The gel remover will begin to separate the paint from the concrete. The longer the gel sets, the less work will be required to remove the paint.
Spray the concrete with a garden hose to remove the gel from the concrete. Clean the concrete with a wet towel if indoors. Allow the concrete to dry completely.
Tape the bottom of drywall, siding, and any other item that is not going to be stained. Staple plastic to the drywall before taping to provide additional protection from splashing.
Remove any dirt, debris, oil stains, or other foreign elements from the concrete by scrubbing with a course scrub brush, soap, and water. Vacuum the concrete with a shop vacuum to remove any tiny particles remaining on the concrete surface.
Remove any debris from inside cracks. Vacuum the inside of the crack to ensure that everything has been removed.
Fill all cracks with concrete glue. A woodworker's syringe has an extremely small needle on the end which allows smaller cracks to be filled easily. Wipe away any excess glue with a damp sponge. Allow the glue to dry approximately an hour.
Mix anchoring cement according to manufacturer directions. The consistency should be that of heavy cream. Press the cement mixture into the crack using a small putty knife. Scrape away any excess, ensure that the cement mixture is smooth with no bevels or creases in the cement mixture. Wait for the cement to dry completely.
Scrape away any excess cement with a putty knife. Sand the area smooth with drywall sand screen.
Draw the desired pattern on the floor with painter's tape. Taped areas will not receive the stain and will stay the original color. This allows for creativity and designs in the concrete. After the first stain has been dried; the tape can be removed from the concrete, and new tape can be applied over the stained area. This will prevent a second color of stain from mixing and creating a color not desired. This can be repeated as many times as desired.
Mix the stain according to the manufacturer's directions. Each process will vary depending on the specific manufacturer.
Soak a scrub brush with water and place the soaked brush in the area where the stain is to be applied. Pour a small amount of stain onto the water spot. Pouring directly into the puddle of water will prevent the stain from creating a darker color at the location where the stain was applied. Immediately begin scrubbing the concrete using the water soaked scrub brush. Push the brush in circular motions. This will force the stain into the pores of the concrete and allow the stain to react.
Vacuum the remaining stain using a wet/dry vacuum. Clean the concrete using a small amount of floor cleaning solution and water. Buff the concrete using a soft buffing pad. Follow immediately behind the buffer with the wet/dry vacuum and a damp mop. This step is best done using two people.
Apply faux finishes using acrylic concrete stain. Mix the stain 50/50 with water. Apply the stain to the floor by dabbing it on with a damp towel. This towel will not be used for another purpose. Be creative on this process. Other faux painting techniques can be used like fan, feather, or sponge techniques. Allow the acrylic stain to completely soak into the concrete.
Mix the clear epoxy sealer according to directions. The mixture should resemble the consistency of paint. Paint the concrete floor with a roller and the sealer. Cover the entire surface of the floor. Use a paint brush along corners and against walls to ensure that every area is covered. A paint sprayer will work if desired.