Pour day in August with 97 degree heat, my finish trowel ruined the whole slab

Last Thursday we poured a 30 by 40 garage slab outside Phoenix and the sun was cooking the surface before we even got the bull float on. By the time I started the first trowel pass the cream was already rubbery, and the trowel kept dragging up little chunks that left divots everywhere. We ended up having to grind down about a third of the slab the next morning. Has anyone else dealt with this on hot pours, or is there a better timing window I'm missing?

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charlie26920d agoMost Upvoted

Man, I used to think hot pours were just about working faster and keeping the mix wet, but this post changed my mind completely. Last summer we had a similar disaster on a small walkway and I blamed the crew, turns out the timing window is way tighter than people admit. The rubbery cream thing is real, once it sets up like that you're basically fighting a losing battle with the trowel. Now I check the forecast and if it's over 90 I either pour at dawn or wait for a cooler day, even if it messes up the schedule. Grinding a slab the next morning is brutal and costs way more than just being patient with the pour.