Pro tip: I found a way to keep a slab from cracking in a tight corner

We had a pour for a garage addition in Kansas City last month with a sharp inside corner. I knew it would crack there. Instead of just cutting a control joint, I bent a piece of 1/2 inch rebar into a tight L shape and set it right in that corner before the pour. The concrete grabbed it and held. Checked it yesterday, and the corner is still solid. Anyone else tried something like that for stress points?

3 comments

3 Comments

the_grace9d agoMost Upvoted

That rebar will likely cause a crack by holding the concrete too rigidly.

torres.grant8d ago

Honestly that's what I've always heard too, but then why do they put rebar in sidewalks and driveways all the time? Like, is it just for heavy truck areas or something? I'm trying to picture where the crack would even show up if the whole slab is locked down. Does it just blow out at the edge instead?

nora1109d ago

Oh man, that's a bold move. In my experience, you're basically trading a predictable crack in a joint for a mystery crack somewhere else. That rebar is so stiff it can't move with the slab, so the stress has to go somewhere. My own garage slab has a crack that looks like it was drawn by a drunk spider, so maybe I'm not one to talk.