If you're looking for a way to completely cover or erase imperfections in your concrete floors, your best bet is to have an epoxy applied. Epoxy has come a long way over the years.
Narrow cracks are typically less than ¼-inch wide and can be repaired using a simple concrete patching compound. Wide cracks, on the other hand, are usually wider than ¼-inch and may require a more involved repair process that involves filling the crack with foam backer rod and then applying a concrete patch.
Slabs with none to minimal cracks, blemishes, and other flaws are ideal for staining. Stains enhance the appearance of the surface; they don't conceal defects. Applying it to flawed concrete will not hide its imperfections, nor will it mask the original color or texture of the surface.
As long as your walkway isn't cracked all the way through, you can coat the slab with a concrete resurfacer, a no-shrink blend of Portland cement, sand, and polymer additives that fills divots and makes a uniform finish.
You can sand concrete to achieve a more refined concrete surface. If you use the proper tools and procedures, sanding concrete can be relatively straightforward. There are different methods of sanding concrete. It can be through either a wet or dry process, influencing the kind of sandpaper you will use.
If you're repairing an indoor concrete slab, like a garage floor or enclosed patio, Quikrete Self-Leveling Resurfacer will be your best option. The product's thinner consistency helps it to self-level as you apply it to your concrete surface.
Concrete Resurfacing
After ensuring the existing concrete slab is in good shape, contractors will add a thin layer of concrete—either over top of or combined with a bonding agent—to level out the surface.
“High-gloss finishes will show scuff marks, and areas on floors where there's higher traffic can get hazy.” Florianovich points out that a matte finish on an interior floor hides more imperfections than a glossy one and also doesn't show dirt as easily. If a floor in uneven, he says, matte is really the only way to go.
To sum it up, most interior projects and all exterior projects choosing between concrete stain or paint are likely better served by a stain solution. Furthermore, horizontal surfaces are best benefited from an acid stain, while vertical surfaces require a professional mineral stain solution.
Concrete Acid Stains are the only true stains with permanent results.
Resurfacing a driveway will extend its lifespan. Adding an overlay above the existing concrete makes it incredibly durable so it can withstand its usual daily pounding from vehicles, foot traffic and harsh weather.
If you are worrying about imperfections in the concrete such as hairline cracks or pock-marks, an epoxy floor coating may be your best solution as it will hide all those imperfections. It is highly resistive to wear and damage due to foot traffic and/or machinery.
With uneven concrete floors, the quickest and most effective remedy for the situation is to use a self-leveling compound that fills in the low spots and makes the floor completely level.
How thin can you pour concrete over concrete? Your new layer needs to be at least 2 inches thick. If it's any thinner than that, it'll easily crack under pressure and won't adequately bond to your surface.
Since cement lacks any natural bonding agents, newly-poured concrete won't naturally bond to the existing slab. You'll need to either use a bonding agent to adhere the two layers together or use an unbonded overlay method.
QUIKRETE® Concrete Bonding Adhesive (No. 9902) permanently bonds new concrete, plaster, and stucco to existing concrete, plaster, and stucco. Eliminates the need for roughing the surface before the application. Exceeds the performance requirements of ASTM C 1059 Type I and II.
Repairs are, hands-down, more affordable than a full replacement. But don't forget to consider how old your concrete is. If it's older, and you choose to repair over replace, you might be repairing it annually. In that case, replacement might be more cost-effective and a better long-term solution.
A dry method is better for other types of businesses that seek high-gloss floors to impress their clients. According to your individual needs, a balance of both methods is recommended. The wet grinding method should be used first when dealing with really hard concrete, followed by the dry grinding method.
Screeds
Screeds come in a variety of sizes and can be a specific tool (also called straight edges or bump cutters), or can be simple flat pieces of dimensional lumber. The purpose of a screed is to smooth concrete after it has been moved into place by scraping away any excess from the slab surface.