Fixing Concrete Issues
How to Fix Blemishes, Divots, Bad Spots, and Cracks. How to patch Concrete.
Cracks and blemishes can be a bummer, but they certainly happen. Concrete isn't perfect and it sometimes shows. Using the tips below will help you overcome those issues.
PATCHING CONCRETE: The first thing to bare in mind is that concrete patching will stain differently than the rest of the concrete. So you'll need to either do the "Touch Up trick" mentioned below, or instead of patching, use the "Epoxy trick" mentioned under Divots below.
In order to patch concrete, you'll need the patch material or product, a concrete trowel, and a concrete rubbing stone. Mix the patch material if it's not a ready to use product and trowel in into the effected area, smoothing it out as best you can. Allow to sit and cure the required time, usually just a day or two, then use the rubbing stone to essentially sand it down flush. That's about it, simple. TIP: To help the patch material bond well, ensure the area is clean and dry. You can use a bristle brush to paint on a Concrete Bonding Agent, prior to applying the patch material. After applying the bonding agent, allow it to sit until it dries some, but is still sticky, then apply the patching. Be sure to not get the bonding agent on the concrete outside the area to be patched, as it will act as a contaminant and prevent the stain from taking.
CRACKS: If the crack is a hairline crack, (you can't place a coin on edge into it) then you should leave it alone. If a coin will fit into it, then you may want to address it. If it's very large then you may want to consider patching it, but if it's not too big, you can fill it with a clear epoxy or urethane after the concrete has been stained and neutralized, but prior to sealing the concrete. IMPORTANT NOTE: If you are using a water base sealer then you must use a water base epoxy or urethane. If using a solvent base sealer then you'd use a solvent base epoxy / urethane.
DIVOTS or HOLES: Of course you can patch divots, but then you'll need to touch them up since the patch material will stain differently, as mentioned in the Touch Up trick below. Instead, you could leave them alone and stain the concrete. After neutralizing and rinsing, once the concrete has dried completely, you can fill them with a clear epoxy. Use a scraper or putty knife so you can smooth the epoxy off even with the surface of the concrete. You want it to be level with the concrete surface and not create a small hump. Once the epoxy has cured, you can proceed with sealing. IMPORTANT NOTE: If you use a water base sealer, you must use a water base epoxy. If using a solvent base sealer then use a solvent base epoxy.
TOUCH UP TRICK: If patching was done, or if there is small spots or blemishes due to paints or other contaminants, they'll show up once you've stained and neutralized. In this case, you can touch up the bad spots with a water paint set, or artist acrylic paints. Since the sealer will enhance and change the colors, you need to apply the first coat of sealer and allow to dry completely. Now that you can see the actual color, you can mix the paints together and blend them to match the floor. If using artist acrylics, be sure and thin them down with water. You want your paint to be water thin. Use a small bristle paint brush to apply it on the blemish and feather it out. Allow to dry completely and apply the second coat of sealer. With clear sealer and especially with wax over that, the layers of clear over the touched up spot helps to visually push it down and into the concrete surface so it tries to blend in and disappear from site. TIPS: If the spots are small then using the one color is fine. But if the spots have any size to them, you'll want mix to match the lighter color seen in the floor, and also mix to match a darker color. Apply the lighter color first, overall. Let dry. Then use the darker color to cut across, break up, or highlight it to help blend it into the floor and hide it better. If working with a darker brown, black, or red slab, sometimes you can use liquid shoe polish that comes in the bottle with the sponge applicator on top. For instance, when staining with Leather Brown, many times the dark brown shoe polish blends right in and can sometimes be applied even before the first coat of sealer, though it's usually best to have the first coat of sealer down to see the actual color.
You can camouflage a lot with the touch up trick, but sometimes the concrete is in such bad shape that you have to do something more extreme to help cover it up. Or, sometimes you may want try and darken or shift the color after its been sealed and you don't want to strip the sealer. In this case, our sealers are tint-able, and paint tint can be added. Tinting sealer is kind of a last resort maneuver, but if you find that you need to go that route, contact us through the contact page and we'll be happy to help with instructions specific to tinting our sealers.