Watched a crew in Denver pour a huge patio without any control joints

The entire slab cracked into a dozen pieces within a month. How do you guys decide on joint spacing for residential work?

3 comments

3 Comments

olivia67013d ago

Pouring that large of a slab without a single joint is just asking for trouble. The concrete has to shrink as it cures, and it needs a planned place to crack. That's basic slab design, not an advanced technique.

flores.emma13d ago

My old boss in Phoenix had a simple rule for driveways. Take the slab thickness in inches and multiply by 24 for the joint spacing in feet. So a four inch slab gets cuts every eight feet. I mean, you can go a little longer with fiber or a good mix design, but that's the safe zone. I've seen guys try to stretch it to ten or twelve feet and it always ends up with a random crack right through the middle. The concrete is gonna crack no matter what, you just gotta tell it where.

wright.leo13d ago

Old boss was spot on. That 24x rule is basically industry standard for a reason. Trying to cheat it just means you're gambling on where the crack shows up, and you'll always lose that bet. Good mix helps, but it doesn't change the physics of shrinkage.