According to my Google search, temps over 90 degrees can cause problems. It's your driveway and your money. You have every right to reschedule.

https://www.sakrete.com/blog/placing-concrete-in-hot-or-cold-weather

Don’t do it - ours slumped and workers also got really sloppy in the heat -9500.00 mistake!

It's done everyday across America. Make sure the builder takes the proper precautions. Keep it wet when the sun is shining directly on it for the first 24 hours and it should be fine.

What summer day and where, will you not see concrete trucks running all day long? It happens all summer long where I am (Florida) and no problems. The people who install it are used to heat. Many (maybe all) contractors use curing agents sprayed atop the finished job to keep the concrete from drying too fast.

Keep in mind that concrete and placing it is a scheduled job, and many mixes are specialized for the job. You can't just tell contractors not to come to work and and concrete trucks to use your product elsewhere at the last ditch minute. The contractor would be justified in billing you the same way a doctor does when you don't show for an appointment.

BTW, heat is not the cause of concrete slumping! Too much water is. Heat might cause the concrete to set faster, but pros are used to these things. They either have a lot of people working quickly or they might add a retardant to the mix. (The Sakete article referenced above is geared toward homeowners who are not experienced placing concrete.)

We live in Texas and they pour concrete all summer long. Our temps can be 90-100 and even above 100 in the summer. I've never heard of an issue in relation to heat.

You'll be fine. And the crew will be fine. You don't do this type of work in Ohio without dealing with sucky weather (I went to Miami - go Redhawks!)

If the crew is large enough and can float/finish immediately, you'll be fine. A fine mist of water after they finish an area will keep the concrete from "flashing" -drying too fast. Don't allow any puddles to form.

Once they complete the pour and pack up, continue to hydrate the surface with water. Once it's hard enough to walk on, or what is commonly known in the concrete world as "green", you can set up a lawn sprinkler so you don't have to stand there with a garden hose.

I'm in Ohio and the temps aren't 90 all day long like they are in the middle of summer. Yesterday I wore a hoodie until around 11am when it warmed up. It was in the upper 80's for about 5 hours. I think you are panicking over nothing.

I agree this will be fine they will tell how to take care of it for the next 24hrs.

Thank you all - at this point, I am second-guessing everything! Didn't think building a house would cause me to go crazy but it has! Concrete was poured early this morning and looks great. The issue is that we have no water service at our new house so I never got a straight answer on how the crew will keep the concrete moist.

Revolutionary Gardens, my two kids graduated from Miami - this is the first time in 7 years we won't have anyone there to visit - don't know when you graduated but there has been a lot of exciting developments in the past 5 years!

That's so cool! I haven't been back to Oxford since '98, but one of my friends is the chief of police for Oxford so I get bits and pieces of what's going on. It's such a great school.

Concrete can be successfully placed under a variety of conditions. In extremely hot weather, ice can be added to the mix, and evaporation can controlled by keeping the slab wet using plastic sheeting or wet burlap. In cold conditions, admixtures can be used along with heating and insulating blankets to prevent freezing.

Neither your contractor nor the concrete supplier want to do an inferior job that will result in an expensive call back.

I wanted a really nice 30x40 slab and wasn’t warned about the heat. Now I have a 30x40 slab that looks like a spiderweb. Talk to your people bout what to do in order to reduce chances of cracking.

If I remember right, it was over 3,500 feet of cracks after measuring it all out. My slab, my problem is what I was told.

There is no way I'd let a homeowner dictate my concrete placement schedule.