How to Acid Stain a concrete floor (a step by step guide)
What is an acid stain?
An acid stain is a reactive way of permanently changing the finish of your floors. The way it works is that the chemicals in the stain react with the lime that is present in the concrete. It penetrates under the surface of the concrete and leaves a translucent color, depending on the composition of the stain and your preferences.
What are the available color options for an acid stained floor?
When it comes to acid staining a concrete floor, you must remember that acid staining is organic in nature. Although having an organic nature is better for the environment-it does mean that the color choices are limited to these 8 basic colors
You can accompany the acid stain with a color dye, this is a non reactive type of staining that opens up more possibilities are far as color and hue go for a concrete floor. Here are the various colors that can be achieved when using a color dye floor In conjunction with an acid dye. It should be noted that a color dye can be used exclusively, meaning you don’t need to have an acid dye to use a color stain on your garage floor.
When selecting a dye for your garage floor, you usually have a choice between a solvent based or water based dye. Solvent based dyes create brighter and more bold colors while water based dyes are more soft and subtle. Solvent dyes are highly flammable however and should never be used in a garage with an open flame. Something to be aware of is that one of the downsides to color dyes is that they are susceptible to U.V. rays and can slowly fade. It is important to use a sealer that is U.V. resistant to protect the color when used in a garage environment.
How to apply an acid stain to a concrete floor:
1. Preparing the concrete:
The floor must be absolutely clean before applying any stain. Use a floor buffer, detergent and degreaser. After you feel the floor is completely free from any dirt or debris, you should test the concrete to make sure that it will accept the stain. It is a very simple process. Simply pour some water over the concrete floor and watch to see if the water is absorbed or beads up. Areas where the water beads up will need some special attention. The way that an acid stain works is that is must penetrate the surface of the concrete in order to react with the lime contained within. If the floor is non-porus, the stain wont work. For these areas, simply use a sander to break up the surface. Avoid grining the floor as it will highlight swirls on the concrete, and will also eliminate the surface later which contains the lime the dye needs to react with. Also avoid any muriatic acid either, as this will also eliminate the lime in the concrete, thus rendering the stain useless.
2. Mask the Walls:
A seemingly minimal step, but you’ll be grateful afterwards that you have done it! We would suggest using standard masking paper, however, in a pinch things like news paper, plastic tarps, or butcher paper can work. Attach the paper to your walls using painters tape, and try to make sure that you have tape about every 6-8 inches. You want the paper to completely cover the wall and cabinet, down over the base boards (if any). Keep the masking tight to the wall, this will help to prevent any additional clean up or damage to the walls during the staining process.
3. Mix the Stain:
You MUST mix the stain in a well ventilated area. Hydrochloric acid the the most commonly used catalyst, so make sure to wear all protective gear recommended by the manufacturer. Pour the mixed acid stain into a two gallon pump with all the plastic parts. It is important that there be no metal on the applicator or spray wand because hydrochloric acid is corrosive to metal. When mixing the acid stain, always add the acid stain to the water rather than water to acid. For hand trowelled floor, dilute the stain with water using a ratio of one part stain to four parts water. For machine-trowelled floors, the mixture will be more concentrated at a ratio of one part stain to one part water. Adding water will also allow you to control the depth of color. Test the sprayer outside to ensure a nice even flow before using it inside.
4. Apply the Stain:
Holding the wand about 18 inches from the floor, apply the mixture in random patterns, making sure to completely saturate the floor without leaving puddles. The areas with more lime will be darker, so don’t be alarmed by darker or more saturated areas. You should let the stain sit for about an hour to dry, and then apply the next coat. Repeat this process until you’ve reached the depth of color you desire.
5. Neutralize the Stain:
Once you have achieved the color you are seeking, acid on the floor must be neutralized. You can do this by using a mixture of 4 parts water to one part ammonia. Make sure before putting this mixture into a pump sprayer that the sprayer is completely clean!
6. Clean the Floor:
Once the stain has been neutralized, you should let it dry for about an hour or so then clean the floor to prepare for the final step. Mop the floor and vacuum up any remaining water. The floor must the completely dry before you apply the seal
7. Sealing the Floor:
When it comes to the sealant, there are many available options which you can pick up from your local “big box” retailer. Usually a high gloss, water based sealant is used, but you can go with something else. Just make sure to follow all manufacturer guidelines and if you have a question about whether or not a sealant will work with your floor, simply ask an associate or check the manufacturer’s website. Use a paint roller to apply the sealand in multiple thin coats vs one thick coat. The sealant will bond better if used in this manner. Allow the floor to dry between coats, usually two is enough.
That’s it! Although it seems like an arduous process, changing the color of your concrete floor is easier than you might think. And as always if you have any questions or would like to request a quote to have us come and stain for you floor- give us a call today