Hot take: I stopped using expansion joint every 8 feet on a large pour near Austin and it cured without a single crack

I know everyone says you gotta cut joints every 8-10 feet on a big slab, but I did a 40x60 foot commercial garage floor last spring and I left it all continuous with a fiber mesh mix. Put in 1/4 inch deep saw cuts at 12 feet after 36 hours and it never split. Has anyone else gambled on tighter fiber dosage or waiting longer to saw and got away with it?

3 comments

3 Comments

seanjackson1mo agoMost Upvoted

I did a 30x50 pour a few years back in San Antonio and tried the same thing with fiber mesh and 12 foot spacing... first real hot summer and I had three hairline cracks running corner to corner. The soil here expands way more than people think, and without proper relief cuts every 8 feet you're basically gambling on the concrete's tensile strength holding up against ground movement. I'd say you got lucky with the timing of that saw cut or the base prep, not the method itself.

lopez.quinn1mo ago

Well, I must've gotten lucky with my pour then... or maybe I just bribed the concrete gods.

nora1101mo ago

Honestly, I gotta agree with the "bribed the concrete gods" vibe from @lopez.quinn. That's pretty much the only way I see this working out long term. I've seen too many slabs in Texas get wrecked by the clay soil just doing its thing, no matter how good the fiber mix is. The timing of your saw cut probably saved you more than the fiber did, honestly. I'd keep an eye on it after a few more seasons, cause that luck can run out.