pouring deck piers in the winter time

Knucklez · 10-19-2009, 11:00 PM

any advice on pouring deck piers during the cold winter months? trying to fill an 8.5"dia sono tube which is 4' deep ending in a 12"dia footing.

Knucklez

CustomBuild · 10-20-2009, 10:20 AM

I just finished working on a 900' long by 28' wide racing horse stable in Saratoga, NY. The project went from Dec,08 to Apr,09. The stables were almost entirely built from concrete block. We placed a large plastic tent over the section being built, and pumped heat in continuously. When that section was done, a crane moved the tent to the next section, and hoses were draped over everything that had to stay warm. The hoses had heated glycol being pumped through them. Then everything was covered in blankets made up of three layers of bubble wrap sandwiched between two tarps. Even the earth around the concrete had to be protected from freezing, to prevent heaving. Your project can easily be scaled down from this model, with a simple wood frame and a tarp. Put a small heater inside the tent, and keep it above freezing for 28 days after concrete placement. Just be careful not to catch the tarp on fire!

CookeCarpentry · 10-20-2009, 03:39 PM

Quote:

Originally Posted by CustomBuild

Just be careful not to catch the tarp on fire!

Why do I feel this is a bit of advice learned the "hard way"?

**Gary in WA** · 10-20-2009, 04:37 PM

Be sure to use gravel under the footings as well as for back-fill. No future danger of frost heave that way. Install 2" foam board around each, 1' down, so the ground frost cannot go deeper. Wrap the sono's with plastic to prevent ice lenses from getting a horizontal grip on them.
Be safe, Gary

CustomBuild · 10-20-2009, 09:12 PM

Lets just say that the best lessons are learned the hard way!

Knucklez · 10-20-2009, 11:06 PM

GBR - i planned on doing all of those things including wrapping sono's with plastic (6mil vapour barrier in my case cause that's what i got lots of on hand) except for the 2" insulation boards. not sure what you meant here.

this is what i interpreted:
i should form a 4 sided box out of 2" thick ridgid insulation with each wall being 1' deep. then slip this box over the sonotobe such that it forms an insulated barrier between the earth and the gravel backfill. it its just below the surface of the soil, i.e. is flush with grade.

birds eye view attached

otherwise, it seems the advice basically resides around finding ways to keep the soil from freezing prior to pier concrete pour and during the curing period (10 days?).

what about add mixtures like an accerlant?

**Gary in WA** · 10-21-2009, 08:31 PM

Sono's: http://books.google.com/books?id=1gg...num=3#PPA31,M1
Insulation: http://www.oikos.com/esb/43/foundations.html http://www.waltersforensic.com/artic.../vol1-no11.htm
Decks to code: http://www.awc.org/Publications/DCA/DCA6/DCA6.pdf
Be safe, Gary

jomama45 · 10-22-2009, 08:31 AM

Depending on how cold it is when pouring the tubes, this should be fairly simple. Try to pick a day to mix & pour the concrete that is above freezing. If it's quite a bit below freezing, it can be frustrating, as small amounts of concrete will freeze suprising fast.

As for accelerant, hot water should be enough. I would simply cover the holes with a 1/2 sheet of foam insulation, straw, hay, etc...

Remember, concrete creates some heat as it initially cures. Trap that heat in & you'll be fine.