Schulze is a distributor of high quality Metzger/McGuire joint filler and floor repair products. For more than 45 years, Metzger/McGuire has been the ind. Importance of Having a Polished Concrete Contractor Perform Joint and Crack Repairs on Polished Concrete Floors. Historically, concrete floors were simply utilitarian, industrial work surfaces. Concrete repairs needed to be functional but not necessarily aesthetically pleasing. With the emergence of polished concrete, today's concrete surfaces. Patching polished concrete floors that are chipped is essentially the same as patching polished concrete floors that are cracked. The chipped area is cleaned and color matching polyurethane patching material is applied over a few coats, with the patch allowed to dry between coats. Once the patch cures, grinding and polishing can be performed.

They are not only a tripping hazard, but cracks in your concrete patio, driveway, or walkway can really compromise the curb appeal of your home. You've let these imperfections linger long enough. Here's how to fix them—easily!

Photo: shutterstock.com

Installations of concrete can last hundreds of years, but sooner or later, most end up developing small cracks, gaps, holes, and crevices. If your concrete path, patio, or driveway has begun to show its age, make the necessary repairs sooner rather than later. After all, what’s a small problem today is only going to get bigger and more difficult (or expensive) to fix. While in some cases it takes a pro to work successfully with concrete, almost anyone can fix cracks in concrete.

Here’s how it’s done.

Photo: shutterstock.com

STEP 1: Choose your concrete repair product.

Concrete surfaces cannot be repaired with concrete. Instead, use a concrete repair mix; these are readily available at home centers and online. Options include epoxy compounds, latex patching material, and mortar mixes. This last option works best to fill large cracks (or chipped edges), while the other products are suitable for cracks in concrete that are ⅛-inch wide or narrower.

STEP 2: Prepare the cracked area for patching.

First, use a small hammer and chisel in combination to knock away any cracked, crumbling, or loose concrete. Chip to a depth of about one inch below the surface plane. Then, rinse the area thoroughly, scrubbing with a wire brush to dislodge any loose, lingering particles.

Bear in mind that this is dusty work. To facilitate cleanup, you may wish to spread a tarp beneath the work area. Most important, be sure to wear the proper protective gear.

Fixing Cracks In Polished Concrete Floors At Home Depot

STEP 3: Fix the concrete crack with your selected repair product.

Epoxy or latex. To concrete cracks ⅛-inch wide or narrower, apply an epoxy or latex patching product (view example on Amazon), mixed according to the manufacturer’s specifications. The material goes on either with a mason’s trowel or a putty knife. Force it all the way into the crack, then smooth the product level with the surrounding concrete. Different mixes cure differently; again, consult the directions listed on your chosen product.
Mortar mix. For larger imperfections in concrete, use a mortar mix. Creating your own mix is as simple as combining one part Portland cement, three parts masonry sand, and just enough water to form a thick paste (though you can also purchase repair mortar mixes, locally or in some cases, online. Moisten (but do not drench) the problem area, then apply the mortar mix with either a mason’s trowel or a putty knife. As you work, take pains to eliminate air pockets by pressing down firmly on the applied product. Finally, smooth the patch so that it’s level with the surrounding concrete. Let it cure for about two hours, then cover the area with plastic sheeting to keep it moist. Sprinkle water under the plastic every day for a few days or until the surface has hardened up.

Prevent future cracks in concrete by following a few tips from the pros.

Select Your Problem

PITTING ON POLISHED CONCRETE

Question:

My company was the contractor on a retail remodeling project that had an existing concrete floor requiring a grind and polish finish. We had to sawcut and remove portions of the floor for new underground mechanicals and then pour these sections back. Our job was to then grind and polish the entire floor to the level of gloss required. On the existing concrete areas, we had no problems. However we experienced problems from the start with the new concrete areas. The engineer involved with the project gave us a method of grinding that allowed us to achieve the correct sheen on gloss tests. Now less than six months later, these areas have failed miserably and the surface is visibly porous and is trapping dirt to the point where floor looks black in areas. The polishing contractor is claiming that this is a concrete finishing issue and the only way to take out the highs and lows of the concrete surface is to grind deep and expose the aggregate, but this would not be acceptable to the owner.

Part of me agrees with the polishing contractor, but during a preconstruction meeting with the polishing company and project engineer, concrete finishing was a non-issue, and the finish did pass initial gloss testing. There have also been some comments about how the store has maintained the floor and their use of chemicals to clean it, which may have caused the concrete finish to fail. Any input you could give us would be great. We are a large general contractor in the Midwest, but our experience in grinding and polishing concrete is limited and we are hoping that this is not going to turn into an expensive lesson.

Polished concrete with a poor mix design or inadequate curing will suffer from premature pitting.

Answer:

Concrete, polished or not, should not pit and be weak on the surface. This usually indicates a mix design or curing issue. With situations like this involving many players, I like to go back to the start and focus on the key issue. In this case, the main issue seems to be that the replaced concrete sections are not holding gloss and polish because of surface deterioration that occurred soon after the floor was put into service - within the first six months.

From the details you have provided, it appears that the replacement sections of concrete are failing and soft, either due to substandard mix design and concrete placement or post-applied chemicals. Polished concrete needs to be properly chemically hardened during the polishing process. This increases the surface hardness and provides better gloss. Lithium or sodium silicate hardeners are most commonly used. If applied properly, these should harden the concrete to a point where soft pitting does not occur, unless the concrete was so substandard that it was really soft and weak to start with.

To zero in on what's causing the floor deterioration, the following questions need to be addressed:

Is there anything different about the replacement areas in regard to mix design and how the concrete was placed and finished? Did the concrete freeze after placement? What you need to look for is anything that might have created a weak surface.
What is the store using to clean the concrete? If a harsh cleaner is pitting the concrete, it would do it to some extent on all the concrete, not just the replacement sections.

In regard to the finish, it is probably one of the most critical parts of preparing the concrete when polishing. The concrete mix design, placement, finish, flatness, and curing are all critical. If you get a soft slab, you end up with what you are experiencing. As for the repair, you can regrind to go deeper and get rid of the pitting, but this ignores the real problem in hopes of a quick fix. If the concrete is weak, the new grind will last another six months and then you're right back to where you started. I suggest taking a core sample or performing a surface hardness test. Also, do some research on the hardener that was used and make sure it was applied correctly and at the right coverage rate.

EFFLORESCENCE ON A STAINED FLOOR SLAB

White efflorescence caused by high water movement pushing salts out of a concrete floo