Resurfacing concrete is an easy DIY project. Take time to prepare everything properly, and allow the resurfacer plenty of time to cure, and you will be rewarded with a garage floor, driveway, sidewalk or patio that looks as good as new. Before you begin with the following step-by-step instructions, however, I suggest you take a quick look at these FAQs about Concrete Resurfacing.
Step 1: Prepare the Surface
Concrete resurfacers should be viewed as cosmetic finishes, not repair products.
If your concrete surface is not structurally sound, you should not even consider applying a resurfacer until the structural problems have been addressed.
What do I mean by "structural problems"? Well, the short answer would be that if it looks like a structural problem, it probably is. Is there evidence of heaving, where chunks of concrete have broken away, sunk or lifted? If so, there is an underlying problem that will probably require that section of the concrete, at the very least, to be replaced. Are there large, deep cracks that run through the slab, or is the surface beginning to disintegrate into little pieces of sand or powder? These, too, describe serious problems that a resurfacer can only mask for a short time.
But if you have minor cracks or pits in your surface, resurfacing can be effective as long as you first repair the damage. See How To Repair Large Cracks in Concrete Floors and How To Repair Small Cracks in Concrete Floors for further information.
Keep in mind that concrete resurfacers are reliable only to a depth of 3/8 inch to 1/2 inch.
Sakrete makes a concrete patcher called Top'n Bond. It has similar characteristics to the resurfacer, but is thicker and needs to be trowel-finished to a maximum depth of 1/2 inch. You can achieve the same effect by simply using some resurfacer, but adding less water than called for.
You want to create a mix that will sit on a trowel, not flow off of it.
Step 2: Clean the Surface
It is critical that the concrete surface be cleaned of all loose debris. A strong spray from a garden hose may suffice, but a good pressure washing will provide a better cleaning. The manufacturers of concrete resurfacers recommend power washing with a 3,500 psi washer.
You will also want to remove any oil stains, paint, or tree sap from the concrete. Try this method for cleaning the stains. If that fails to get all of the stain out, consider applying a sealer over the stain.
Step 3: Mix It Up
Plan to mix one bag at a time. For best results, mix with a 1/2-inch drill and paddle mixer. One 40-pound bag will usually require 3 1/2 quarts of water. Use warm water in cool temperatures, and cold water in warmer temperatures.
Pour most of the water into a clean 5-gallon plastic bucket. Empty most of the contents of a 40-pound bag of resurfacer into the bucket and mix for several minutes into a smooth, pourable consistency. Let the contents rest for a few minutes, and then mix it again. Add a little more water or resurfacer, if necessary, to create a pourable mix with the consistency of syrup.
Step 4: Wet It Down
You want to pour resurfacer onto an already moistened surface.
That way, the concrete will not draw any of the moisture out of the mixed resurfacer. So, just prior to applying resurfacer, give the surface a good, cooling spray with the hose, then sweep any standing water off the surface.
Step 5: Apply the Resurfacer
The easiest method for applying concrete resurfacer is to pour a small amount on the surface, then immediately begin spreading it evenly with a light, long-handled squeegee. You can create clean, professional-looking edges with a concrete edger, but only if you get to them within the first 15-20 minutes of application.
Step 6: Scuff the Surface
If the resurfacer is allowed to cure without any finishing touches, it will create a smooth surface. That's often what you want in a garage. But the smooth finish can be slippery when wet, which makes it less desirable on a driveway, sidewalk or patio surface.
To add some bite to the finish, use a long-handled broom to make full strokes across the surface. Plan to do this within five minutes of application, while the mix is still wet enough.
Step 7: Let It Cure
As concrete cures, it hardens and becomes stronger. Quikrete and Sakrete claim that their resurfacers achieve its maximum compressive strength of 4,500 psi after 28 days. At seven days, it is already at 3,000 to 3,500 psi. But you don't have to wait that long before using the surface. Wait about 8 hours before walking on resurfaced concrete, and at least a full day before driving on it.