This concrete garage floor is 3 years old. It has these quarter-inch wide sharp joints cut in every 12 feet. All settlement/curing cracks are in the joints, but I don't understand why they were cut so sharp and deep: All the depth and edge seem to accomplish is to collect dirt and provide a home for moisture and pests.
At this point is it OK to fill them in – at least partway to reduce the space available for dirt to accumulate? Or are they serving some other ongoing purpose?
Best Answer
You could have caulked them a month after the slab was poured. You can caulk them now. Or vacuum/scrape them out and caulk them now.
Saw-Cut control joints (as opposed to "tool-formed while the concrete was wet" control joints) are inherently sharp. They are less expensive than formed joints. They need to be deep enough to accomplish the goal of having any cracks that form, form at/in them, not at random.
Use a caulking compound made for use on concrete. If the width precludes setting a bead in the top of the joint that will stay put, fill them with foam backer rod and then caulk on top of that.