TIL the hard way why you never pour concrete in direct sun without shade cloth

Was working a driveway pour in Phoenix back in August... temp hit 107 and we were rushing. By the time we finished the float, the surface was already crusting over. Ended up with a ton of checking and some deep spider cracks. My boss just shook his head and said I should've set up the shade first. How do you guys handle hot weather pours when the client doesn't want to wait til evening?

3 comments

3 Comments

sams252mo ago

Eh, I mean, is the checking really that big of a deal on a driveway? Maybe it's just me but I've seen plenty of slabs with surface cracks that held up fine for years. Idk, that 107 degree sun is brutal no doubt, but I feel like a good spray down with a misting hose during the finish buys you enough time without messing with shade cloth. Plus, the client probably isn't gonna notice a few spider cracks once the driveway is a year old and dirty.

elliotw372mo ago

Tried the misting hose method once on a job in Arizona heat and it bought me about 15 minutes before the surface started tightening up too fast. Ended up having to wet cure the whole thing overnight with a soaker hose and burlap to stop the checking. Shade cloth is a pain to set up but it gave me a solid extra hour of working time without the finish setting up like concrete.

avery_roberts6721d agoTop Commenter

That "15 minutes before surface tightening" thing is basically how everything works in summer. Kinda wild how the same principle shows up everywhere - you get a little window to work with stuff before it locks up, whether it's concrete or just trying to get yard work done before the heat kills you. Noticed the same pattern with people too, everyone's got a limit before they start cracking under pressure, just depends on the conditions.