Concrete joints are an essential part of the slab, allowing individual sections to contract during the cure or shift and move without cracking or causing damage to adjacent pieces. If you are working on a concrete slab, we’re walking you through the steps you need to take to prepare, fill, and finish a concrete control joint to get a flawless, professional result. To accompany this step-by-step guide, be sure to watch the video below to see how our team completes the task.

Preparing the Concrete Joint

The first step is to use the use a 110V shrouded crack/joint saw. This is a compact machine with a rotating saw blade that goes down into the concrete joint, cutting out the old filler and cleaning out the void. Rear wheels are attached to guide it easily through the joint and ensure a precise straight cut. A dust collector is attached to the saw to remove debris and dust and clean out any dust from the void.

As you see in the video, this is not a single-pass task. Instead, you’ll want to run the joint saw through the joint over multiple passes to make sure it’s completely empty and clean.

Filling the Joint

Once the joints are cleaned out completely, it’s time to refill them. We use a urethane joint compound that can flex as it dries to create a strong, permanent bond between the two slabs. Thoroughly mix the joint filler using the manufacturer’s direction, then pour some into a smaller container for increased control and precision.

Pour the compound filler directly into the joint, taking slow passes, allowing time for the filler to sink all the way into the void and ensure the compound reaches the top. Don’t worry about overflow, it’s more important to make sure the joint is 100 percent filled with compound.

Finishing the Concrete Joint

After waiting 18 hours for the joint compound to completely dry, you can then begin the finishing process. Using a compact concrete grinder, go over the joints repeatedly until the joint is flush with the slab. During this process, we highly recommend using a dust collector for safety as well as easier cleanup. Once it’s complete, run over the area with a microfiber mop to get any residual dust and move on to preparing the slab for coating, if needed.

Order Your Surface Preparation Materials Today

If you need surface preparation equipment, including compact floor grinders or tooling, we can help. Reach out to our sales team today at  +1 (815) 941-4800 or fill out the contact form below for a quote on materials.