Cold weather concrete placing

House Repair Talk

Help Support House Repair Talk:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
When our weather gets close to freezing the batch plants close down, and if we have poured a foundation and expect freezing we have to blanket the concrete to keep it's heat in.
 
The concrete gives off heat during the curing process too which helps it stay warm in the short term.

We recently poured a concrete retaining wall. The contractors built a temporary enclosure around the entire site to keep the wind out. 24 hours after the pour I placed my hand on the wooden form and it was warmer than the walls inside my heated house even though the outside temperatature was well below freezing.
 
Cold weather placing should not be a problem IF the grade you are placing it on is not frozen. Finishing will be delayed and fly ash is not a good thing to have in a mix because it can be unpredictable.

Curing is the key item since that can affect the and performance of the concrete. Keep it covered an insulated for the first few days and rely on the heat of hydration from the curing concrete to maintain decent temperatures.

A good supplier should have the ability to provide the concrete since it is no surprise when there is a winter "cold snap". Here, the larger ready-mix companies will close some plants to funnel the lesser winter volumes through the plants that have the ability to provide concrete in the winter (multiple cement silos - regular and high early cement), the ability to store aggregate in enclosed and possibly heated bins and the ability to provide warm mixing water to provide better concrete to a cold site. Obviously, calcium chloride is avoided at all possible times for the usual reasons.

One weak link in cold weather concrete is trying to batch good concrete into a truck that has been outside at 0F overnight, so some producers run a quick "waste batch" of some sand and warm water(140F) to take the chill off the mixer and improve the real batches that follow.

Dick
 
I had a 24x40 slab poured for a walk out basement on an existing house. An enclosed space but not heated. Vapor barrier, rigid insulation, mesh and pex tubing for an eventual boiler. Done during a 20 degree cold snap in NE. They said they'd still pour, just a hotter mix. They told me that it would feel warm to the touch but I could walk on it the next morning. From an adjoining space I watched them work and left the door open overnight. It opened to a 1st floor landing which opened into the 2nd floor main living area. When I got up in the morning the house felt like a sauna. I just had electric bb heat at the time. All my windows were soaked from condensation, as were the exterior walls.
Still 20 degrees outside, I opened most of my casement windows to vent the house. Went out to my shed to get a fan and portable heater and my neighbor came running out of his house yelling that my house was on fire. Looking up at the house I had steam pouring out of the windows. So thick it looked like smoke.
The basement walls were insulated but not covered. Concerned about mold forming, I had to pull down all the insulation to dry the walls and ceiling. Ran heaters and fans for about a week to be sure everything was dry.
I was surprised at how much of that water evaporates out. Next time I'll just wait for warmer weather.
 
today i pored a 2' x 2' x 1' footer for a steel post in my basement that's about 40 i put a heater on it and some r19 over it ill be leaving them on for at least 3 days cant wait to get the foundation done so my power bill goes down ill post pic's of the job in different thread
 
wednesday we placed 2 deck column (2' x 2' x 1') footers & covered conc w/r19,,, we'll start deck tomorrow if it doesn't rain & finish wednesday,,, our low temp's been 19f
 
Back
Top