Temps

[kurt]

What say the brethren regarding minimum temps for a concrete foundation placement?

Getting close, people are nervous, all eyes on me to make the call. I'm conservative.

What do the upstate NY folks think?

[Brandon Whitmore]

Your question got me curious, so I read this:

http://www.na.graceconstruction.com/cus ... B_0106.pdf

Thanks for making me learn something today.

[hausdok]

It depends,

Go to TIJ's library and download FM5-428 - the Army Concrete and Masonry Manual. It's on page 5-42 and 5-43.

Click here

ONE TEAM - ONE FIGHT!!!

Mike

[kurt]

Thanks both. They're saying it's OK at temperatures lower than what I've always considered OK.

I was just looking for credible reference. Got it.

[Garet]

Concrete can be placed in sub-freezing temperatures, provided that the contractor takes appropriate steps to keep it from freezing before it sets up. With flatwork, that's hard to do. With a footing it's pretty easy (assuming the ground is not frozen and assuming the contractor is prepared ahead of time). A wall is harder because it has more surface area. The smaller the placement, the harder it is to keep warm.

We placed footings once for a parking garage with temperatures in the teens. Pulling the blankets off 3 days later they were still steaming. Of course, they were 3' thick and 8' wide.

One more thing. If someone is taking cylinders, they have to either be placed under the same blankets as the work itself or taken into a lab to cure. Don't even think about putting them into one of those little insulated plywood boxes on the job site. They'll freeze before they cure and crumble to pieces. Not that I would know from direct experience. [:-taped]

[kurt]

This is basic footing and formed wall, 12". It'll be OK.

Thanks for the personal story. [:-angel]

[:-shake]

[David Meiland]

Every batch plant rents concrete blankets, and probably in the perfect size to cover sidewalks and footing/wall forms. I'd easily do that with temps in the 20s... below that (doesn't happen here) I might start heating them after the pour.

[Jerry Simon]

Every batch plant rents concrete blankets, and probably in the perfect size to cover sidewalks and footing/wall forms. I'd easily do that with temps in the 20s... below that (doesn't happen here) I might start heating them after the pour.

How fancy. We used straw to cover our footings.

[Jim Katen]

I worked on a job last year that involved casting 15 slabs. The contractor had a special inspector who monitored ground temperatures and weather forcasts and told him when he could & couldn't place the concrete. On top of that, the redimix plant simply refused to deliver when they judged conditions to be inadequate.

As others have said, the footings usually aren't a problem. You can cover them up with blankets. Finding windows to do the slabs, however, was a bitch. One slab waited for 6 weeks - it was either too cold or too rainy to cast the damn thing.

[kurt]

That's probably what I'll be doing. I'm getting paid to hang around and make sure nothing stupid happens. I aim to fulfill my obligation.

[Jim Katen]

That's probably what I'll be doing. I'm getting paid to hang around and make sure nothing stupid happens. I aim to fulfill my obligation.

Get a thermometer and stick it directly into the soil. Keep a record of the temps. It works better than measuring the surface temperature. If the sun is shining, the difference between the termperature at the surface and the temperature an inch down can be dramatic.

[kurt]

Good idea. Keep a record of temps; I like record keeping.

It also justifies what will be largely me standing around watching.

[Jim Katen]

Good idea. Keep a record of temps; I like record keeping.

It also justifies what will be largely me standing around watching.

You can charge more if you have a really fancy looking thermometer.

(Also, be sure to get custom imprinting on your hardhat.)