Trick to Make a Concrete Slab Perfectly Square
LESLIE: Joe in Arizona is looking for some help with concrete. How can we help you?
JOE: Yeah. I was trying to lay out a pad in my backyard. Yeah, I have nothing to measure off of. How do I square it up?
LESLIE: Square it to your house.
JOE: No. It’s not on the house. It’s detached.
TOM: Oh, okay. That’s a great question. How do you make sure it’s absolutely square? A very simple little trick. You measure diagonals. You measure from opposite corner to opposite corner and if those two numbers equal, then it’s perfectly square.
JOE: Okay. So you just …
TOM: (overlapping voices) You got that?
JOE: Just from opposite corner to opposite corner? There’s no particular theorem for it or anything?
TOM: (overlapping voices) No, it’s … no, it … Well, there’s a more … I could give you a more complicated way to do it. (laughing) But why bother?
LESLIE: (laughing) Do you want the want the easy way or the hard way?
TOM: Yeah. I mean how big is this concrete pad going to be? What, like 10×10?
JOE: It’s going to be 8×12.
TOM: What is it?
TOM: 8×12? Okay. So cut your eight-foot length; cut your 12 foot length. Stake them out or you could do it with string and adjust the string and then build the forms right to that. But you measure diagonal corner to diagonal corner and whatever that happens to be, if it’s the same in two directions, then it’s absolutely guaranteed to be perfectly square.
LESLIE: And it’s pretty easy because if you get two people on two tape measures, as you’re seeing, say, maybe one corner is off half an inch, you can just jog the whole frame slightly to match it up and get things even.
JOE: Okay. Alrighty. I thank you.