How cold can it be and still pour concrete. Should take roughly 3 yards. Adding on to the porch to make a 3 season room. I have been to busy to start it earlier but the wife wants it now if not yesterday. I don't mind working in the cold just not in the snow.
(11-28-2023, 07:51 PM)gear jammer Wrote: [ -> ]How cold can it be and still pour concrete. Should take roughly 3 yards. Adding on to the porch to make a 3 season room. I have been to busy to start it earlier but the wife wants it now if not yesterday. I don't mind working in the cold just not in the snow.
Tips for Pouring Concrete in Cold Weather (thespruce.com)
How cold is it. if you tent it you can get by real easy to just above freezing. then you will need some sort of heat. or if it is not freezing you could cover it as concrete creates heat as it sets. You also can have them add calcium to the mix.
3 yards is a good bit. More than I'd want to mix from bags. Have it delivered mixed with the cold weather additive it it's too cold. And still, tent it if possible
(11-29-2023, 07:59 AM)Snipe Hunter Wrote: [ -> ]3 yards is a good bit. More than I'd want to mix from bags. Have it delivered mixed with the cold weather additive it it's too cold. And still, tent it if possible
Most cold weather additives contain Calcium Chloride (CC) CC has very adverse effects on reinforcing steel. One could have the concrete mixed with hot water and once placed and finished covered with hay or straw assuming overnight lows are above freezing.
I work on DOT projects and this comes up a lot. Here’s some tips-
Don’t pour on frozen grade. Depending on how cold, use blankets and/ or tent+heater to keep the subgrade from freezing.
First night is most critical. Try to find a 3 day window where it won’t freeze and schedule pour around that. If not, find a one day non-freezing overnight. Worst case, blanket and or tent when you pour.
Either way, blankets and or tent+heat is a good idea. Ideally, keep it 50 or above for 7 days (3 minimum). Blankets- if you can rent blankets for curing concrete, those are best. Workaround- use moving blankets/ fiberglass insulation/ foam sheets, something with some R value to hold in heat. Then plastic on top. If it’s really cold, build a frame around your slab and make a plastic sheeting/ tarp ‘tent’ and add heat with a propane or whatever heat source. It will help a lot to keep the cold wind from blowing on the top so whatever you do, keep it covered in plastic 3 day minimum but the longer the better. I don’t recommend calcium chloride additive. Instead, I would bump up the cement in the mixture . If you’re pouring yourself, use hot water (concrete plants will already do this if it’s cold, but ask to make sure).
If it were mine- preheat subgrade, pour and finish (increase cement by20%), blanket + plastic as soon as it’s hard enough to not leave marks, tent + heat to maintain 50F for 10 days (7 is probably ok, but 3 days minimum). That may be a little overkill but do something along those lines and you’ll probably be ok. And not sure where you’re at, but this advice is assuming overnight lows in the teens and highs in mid 30’s during the day, ie typical Indiana winter. I would not pour if it’s going to stay in the teens or below for days on end.
Adding- if it’s not going to dip below freezing at all, or just for a couple hours, then I would just add 20% cement and blanket/ plastic. Ideal cure is 50F but as long as it doesn’t freeze your concrete will be perfectly fine, it will just take longer to reach full strength. Use black plastic if possible for solar gain. And if I wasn’t clear, make sure your plastic is held down properly, ie- not flapping in the wind along the edges. And if you do need to use heat- concrete puts out a lot of heat for 24 hours, then a little heat for a couple more days, then very little so the heating on day 2-3 and beyond is more important than adding heat on day 1.
I was going to buy the concrete delivered. And giving it a lot of thought I'm going to hire it done. Talked to a contractor this morning and he's looking for work to keep his crew busy. He does concrete and buildings. It makes sense to me and it would get done quicker than me working alone. Asked him about framing and he has good men to frame it and he has 2 real good finish men to do the inside. They have work for now else where but he would schedule them in. He comes with good recommendations from people I know. I pretty certain I'm going this route instead. My son does this type of contracting work around Chicago and he's covered up begging for help.
AJKoontz reply is spot on, as is the link to cold weather concreting...
Good luck with the pour...
thermal/ insulated blankets. might be able to rent em