Tips to Repair Cracks and Pitting in Concrete Garage Floors

A popular adage in the concrete industry is that there are two guarantees with concrete: one, it will harden, and two, it will crack. Contractors can attest that cracking and pitting are everyday causes of complaints in the concrete industry.

If you're new to concrete polishing or you're looking for another valuable service to offer your clients, then crack repair is an option that you might want to explore. Before offering this service, however, you should know how to repair cracks and pitting in concrete floors.

In this article, we've highlighted the most important things to know about cracks and pits. We've shed some light on what cracks and pits are, what different types of cracks and pits are there, what causes them, how to repair them, and the equipment to use to repair cracks and pitting in concrete garage floors.

What are the Different Types of Cracking?

Real concrete professionals should be able to tell what kinds of cracks and pits they are looking at. As such, an understanding of the different types of cracks and pits is highly required when tackling concrete floor preparation tasks.

Cracks are splits or openings in the concrete floor surface. They run from a hairline to a few inches wide. Pits, on the other hand, are random small, deep holes with jagged edges. At times, pitting can cover large areas of the concrete floor.

There are three main types of cracking, including shrinkage cracking, structural cracking, and craze cracking. As a decorative concrete contractor, you should know how to repair the different types of cracking.

What Causes Concrete Floor Cracking and Pitting?

There are various causes of cracking on concrete floors. It can be the result of one or a combination of factors like thermal contraction, drying shrinkage, and pressure build up at certain points.

Pitting, on the other hand, can occur from natural aging, climatic conditions, and abuse or misuse. In some circumstances, pitting occurs from improper or inadequate preparation of the final sub-base, inadequate mix, and improper use of an accelerator.

Tips for Repairing Cracks and Pitting in Concrete Garage Floors

Regardless of the reason for cracking or pitting, there are a number of tips that will help you to take the worry out of repairing concrete floor cracks and pits. The following are some helpful tips on how to repair cracks and pits in concrete garage floors:

1. Clean the surface

Cleaning the garage floor is a crucial first step. Clean the cracks and pits well to rid them of dirt, debris, and loose bits of concrete. You can clean small cracks and pits with a scrub brush or broom. For larger cracks and pits, a sturdy broom will do fine.

If you prefer, you can spray the concrete cracks and pits with a hose to flush out any remaining debris, taking care not to allow the debris back into the cracks and pits. The idea is to have a perfectly clean surface.

2. Fix major floor blemishes

Fill any cracks and pits that are more than ¼-inch deep. You can use a crack sealer or caulking to fill cracks and foam backer rod for single pits. Be sure to put tape on each side of the crack or pit before filling to keep excess filler material from spreading onto the garage floor.

You can use a paintbrush to apply bonding adhesive to the walls of the cracks and pits. Use a putty knife or trowel to smooth the patch, and then remove the tape.

3. Apply selected polymer

When dealing with small cracks and pits, (less than 1/8-inch wide), it's recommended to use a polyurethane/polyurea polymer. Some floor solutions require you to pre-soak the floor with water, while others require you to apply a coat of primer first with a paint roller. You should follow the manufacturer guidelines. Then, you should mix the resurfacing solution and pour it directly onto the concrete floor.

For larger surface areas, you can use a floor squeegee. For smaller surface areas, a metal trowel will do fine. Push and pull the resurfacing solution with the squeegee or metal trowel until you fill all of the cracks and pits. Be sure to make several passes from different angles to ensure total filling. Check the surface periodically to see if you need to apply a second coat. Give the polymer time to dry or harden.

4. Polish the concrete

After the polymer has hardened, you should go ahead with the polishing process to reveal a beautiful, polished look. At this point, you will need a commercial concrete grinder such as the Onfloor OF16S-L multi-surface planetary concrete floor grinder.

To start the grinding process, attach a 40-grit metal bond diamond tool onto the planetary head concrete grinder. You can choose a suitable tool from one of Onfloor's diamond tools that are designed for this task.

With your grinder, go back and forth across the concrete garage floor to level it. Be sure to grind around the edge of the room as well. Use a vacuum to remove dust from the surface. Onfloor also has a variety of dust collection vacuums that are suited for this task.

After removing dust, you should then attach an 80-grit metal bond diamond tool to the grinder. Go over the surface again, and clean the dust. Repeat this process with a 120-grit metal bond diamond tool and clean the surface again.

The next step involves using a 50-grit resin-bond diamond pad to the grinder. The purpose of using the resin is to give the polisher extra cushioning as it smoothes and polishes the concrete surface. Remove the dust and progress to 200, 500, 1,000, 2,000, and 5000 grit resin-bond pads. Onfloor has a variety of resin-bond diamond pads for this purpose. Be sure to clean the floor after each successive pass.

Final Thoughts

Repairing cracks and pitting in concrete garage floors doesn't have to be a daunting task. With the right equipment and tools like the ones provided by Onfloor Technologies, you will be able to accomplish the tasks at hand quickly and efficiently.