Saw a parking lot in Akron that made me rethink my whole approach to control joints

I was making a delivery at a strip mall in Akron last week and noticed their parking lot had these perfect control joints spaced exactly 10 feet apart. Not a single crack anywhere on a slab that had to be at least 15 years old. I asked the property manager who did it and he said some old timer named Joe who used a hand groover instead of saw cutting. The grooves were deep and clean, maybe 1.5 inches down into the slab. Makes me wonder if we overcomplicate things with expensive saws when a good hand job and proper spacing does the trick. Has anyone else seen lots that hold up better with hand cut joints vs saw cuts?

2 comments

2 Comments

gibson.sean27d ago

Read something similar on a construction forum a while back, a guy swears by hand grooving because the tool compresses the concrete at the cut instead of just removing material. Makes the joint tighter and less likely to spall over time. Joe probably knew what he was doing with that depth too, 1.5 inches into a 5 or 6 inch slab is about right for controlling the cracks. Might be the old school way but sounds like it works.

barnes.brian27d ago

That 1.5 inch depth into a 5 or 6 inch slab is throwing me off. I've always read the rule of thumb is a quarter of the slab thickness, so that would be like 1.25 inches on a 5 inch slab or 1.5 on a 6. But Joe going with 1.5 no matter what? That sounds like he was just eyeballing it and hoping for the best. My old man always said an extra quarter inch can turn a control joint into a weak spot if the slab's on the thinner side. Crazy to think a guy could get away with that for decades without it biting him.