Changing the color of stained concrete requires stripping the existing color using a strong acid, exposing a fresh surface and applying a new epoxy finish. Change the color of a concrete floor with tips from a construction specialist in this free video on decorative concrete.
OK we're going to change the color of this garage. It's stained right now so what we need to do is strip off the old coating, get down to some a good new canvas and then we're going to put a colored epoxy. There's different kinds of epoxy you can put over it, you can do a color flake epoxy, a color epoxy, metallic epoxy and many other things can be done but we're just going to go with a colored epoxy over this one. So what I need to do is strip the paint off there to not only get off the old paint but to prep the concrete and I'm going to use a shop blaster for that, it shoots out little beads of steel and it recycles it so it's not going everywhere and it not only strips the paint but also profile my concrete so that my epoxy will go on there and last. So this is my shop blaster and I have a vacuum, a double filtered vacuum that hooks up to it so it makes it dustless and pretty much it's like a little shotgun, I'm going to be just shooting little tiny BBs at the surface to strip that off. OK now I've completely stripped this floor with the shop blaster, my grinder, just some good old fashioned scrubbing it, now it's ready to get blown off and vacuumed which I just completed and now it's ready for it's epoxy so we'll get a nice good bond because it's profiled properly. OK now that I have this garage floor prepped I'm going to go ahead and mix up my colored epoxy and it's a two component epoxy so you'll mix it together for two minutes. I have my handy brush and roller. I'm going to use my brush for my expansion joints and for the edges and then I'll go ahead and roll out the big areas. OK and before you put your epoxy coat down, your colored epoxy, you're going to want to make sure it's nice and clean after it's prepped and then I use a paintbrush and a roller so I'm going to edge with my paintbrush. I'm going to do the expansion joints and all the edges and then that way I can just go over it with my roller and do the main body of it. You want it to dry for about 12 hours, it depends on the temperature, it depends on which epoxy you're using. I use a two component epoxy and I usually wait until the next day before I put urethane over the top of it. OK now that I have my epoxy coat down in this garage I'm going to go ahead and put my two part urethane coat over it and same deal, it's an A and B component, mix it together for two minutes and edge and roll just like I did with the epoxy. After your urethane coat is down, you're going to want to wait 48 hours before you put any car traffic on there or drag anything heavy across that and sometimes it may take longer depending on the temperature. You never want it to be freezing overnight when you're doing it, you don't need epoxy or concrete overlays but usually about 48 hours.