Winter Concrete Construction
Concrete Construction During Winter
We often get questions about winter construction and more specifically whether or not concrete construction can occur in the winter months. Although not ideal, it is very normal for concrete construction to occur during the winter months.
We just broke ground on an addition for a commercial car dealership building and it’s already been snowing. Last winter we built a 36,000 sq. ft. commercial building in the dead of winter. As you can see in the photos we we’re right in the middle of pouring concrete footings for the building in the dead of winter.
Complications of Pouring Winter Concrete
Winter concrete construction is certainly more complicated for several reasons.
- Concrete achieves strength by a chemical process called hydration. The process happens when water combines with Portland cement. The process works best when the hydration water is warm. The cold weather in the winter slows down the chemical reaction and therefore slows down the rate of strength gain. Ultimately all that really means is you need to wait longer before you apply any significant structural loads to the concrete.
- In order to combat the low temperatures and slow rate of hydration, chemical accelerators can be used. In the past calcium was used to accelerate the chemical reaction and increase the strength gain of concrete. However, over the years we’ve discovered that calcium helps cause corrosion in the reinforcing steel. So today we use non-chloride accelerators in order to protect the reinforcing steel from corrosion.
- Concrete plants actually use warm water when mixing concrete in the winter. As you can imagine this can be quite costly due to the shear volume of water that must be heated.
- Finally insulated blankets and heaters are used to protect concrete from freezing when it’s first poured. This allows the chemical process of hydration to continue and therefore continue to create stronger concrete.
So the answer is yes you can continue concrete construction in the winter. It’s typically more expensive and slower going. However, there are times when winter concrete makes sense from a schedule point of view. Be sure to ask your concrete construction contractor whether they have experience doing winter concrete work. Make sure they are responsible for covering their work with frost blankets.
Some concrete plants can also heat the aggregate and the sand / portland cement in addition to using hot water depending on the temperatures you are dealing with and the distance your work site is from the plant.
I just recently finished a footer for a single car detached garage we are building, luckily we had a few days of warmer weather when we were ready to pour :-)
Nice description of the process in winter months though…
We started building our home in November 2009. I think I asked you about it at the time. :) Good write up here. It worked for us in Utah. :)
Did you have to use a ground-thaw heater to break ground or wasn’t the frost very deep?
Jeff – In that situation frost wasn’t deep enough to need that. We were able to excavate through the frost and protect the exposed grade with frost blankets prior to placing the concrete. Depending on how deep frost is we certainly have used ground heaters in the past.
We are about to bullid a new deck in Northern Virginia. Currently we are experiencing temperatures in the low 30’s.
Should we be concerned about the concrete work and does anyone have advise or experience with this?
Alex – Shouldn’t be a problem. This week we’ve been pouring a huge foundation for a commercial building project here in NH and yesterday it was only 15 degrees.
Couple things you should think about. After the concrete is poured it’s a good idea to cover the foundations with frost blankets or other heavy duty tarps that will help keep heat in during the first 12 to 24 hours. It’s also a good idea to have the concrete supplier use hot water and a non-chloride accelerator.
A state of Florida general contractor since 1973. I must ask regarding this foreclosure thing that is seriously impacting the entire construction industry. Who should pay the price for this dance the homeowner, the banking industry or the federal government?
I am sorry if I offend but I have been in this business for forty years and suffered through a lot of ups and downs, this one is beyond my experiences to date and in my mind it is a condition that did not need to happen. It started in the Carter Administration and only now has come home to roost.
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what does winter services include for concrete work
Typically winter “charges” will include special chemical admixtures to help the concrete cure in cold weather, hot water used to batch the mix (to prevent freezing), blankets to cover up the concrete after its placed, and sometimes heat pumped into temporary tents.