Replies

1. 
   Marson | Jan 30, 2009 10:39pm | #1

   Yes is the short answer. However, you will have to maintain a temperature above freezing for at least 48 hours after the pour. Usually that involves some sort of shelter and a heat source.

   You don't say how you will get through the frozen ground. That is usually the hard part.

   Where I live, there are contractors who can drill helical piers. They will even thaw the ground as part of the service. We get them for about $350 each, which when you consider the time and trouble to get a pier in the ground in the winter isn't a bad price.

   If the pier is on the edge of the deck, it is also possible to temporarily support it and come in the spring and dig in a footing.

1. 
   ncproperties | Jan 30, 2009 11:17pm | #2

   Yes, even above ground structural and composite decks can be poured below freezing.  My personal fav. of task for wintertime activity here in Mich.

   As Marson said just keep it warm.  Best way is to use what are known as concrete blankets or insulated blankets.  It works because the curing/drying of concrete chemically generates heat.  Lots of it in some cases.  Best job for winter concrete is to be with the footing crews stripping forms in the morning, you can actually stay toasty doing this as steam rolls of the massive monolithic footings when the forms are pulled.  In fact the Hoover Dam was poured with cooling pipes in the concrete just so it didn't get too hot and "blow" the concrete or cook it.  They say if it hadn't been poured in a lego block fashion and was one big pour it'd still be cooling off for another 100yrs.

   Best route for you is to prop up a simple lean too with trap and leave a space heater in there over night, same can work for thawing the ground in some cases.

1. 
   tturci | Feb 02, 2009 05:18pm | #4

   One benefit that I have is the fact that it is on the South side and it is somewhat insulated from the wind. Just have to make sure as you said it stays warm. Do you think I should add more cement to the bag mix or just use "fast set" type? I know I can definitely build something to keep it warm for awhile. Will look for a stretch of warmer days before attempting.

   Thanks. 

1. 
   Haystax | Feb 02, 2009 08:19pm | #6

   I find that digging the hole is the hardest part. A steel bucket or cut down 55 gallon drum works well with a propane weed burner to create an "oven" to place over the ground in the pier location to thaw out the frozen topsoil.You can get as fancy as you want for warming the aggregate, adding extra portland or buying the accelerant type. If hot water is easily available then that is the easiest. You can also use the cut down 55 gal drum for heating up your mix.I then hang a light bulb or heat lamp, don't need much just enough to keep above freezing, in the cut down drum and drape a concrete blanket over the top. Works pretty well for me. Works really well if you've got a magnetic lamp base to hang the light bulb inside the drum;)Has worked on piers here when overnight temps are in the single digits, never had this method inspected or tested though.

   Edited 2/2/2009 12:30 pm by Haystax

1. 
   tturci | Feb 02, 2009 09:25pm | #7

   Thanks for all the tips!

    

2. 
   DanH | Jan 30, 2009 11:27pm | #3

   Several years back I watched a crew near our building pour footings and build a 20-foot-high CMU firewall in the winter when temps never got above zero F.

   The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness. -John Kenneth Galbraith
3. 
   Catskinner | Feb 02, 2009 05:57pm | #5

   1) Make sure ground is not frozen. Roofing torch or weed burner is handy.

   2)Warm the rebar up a little right before you pour.

   3)If you are using a pre-mixed sack product like quickrete, batch with hot water.

   4) If you are mixing your own, pile the sand and gravel up over an old scrap of metal pipe or culvert laying on the ground and run the roofing torch down the pipe for a while. The sand and gravel will heat up nicely.

   5) Quickrete makes a product called Thermalube, which is a set accelerant. It works.

   6) If you are using pre-mixed sack products, then yeas, definitely add a shovel or two of Portland to each bag.

   7) The first day is not the one you need to worry about as much as the second day when the reaction heat starts to dissipate. Straw is commonly used, concrete blankets are better.