Until April, Anchorage, Alaska’s building department required a contractor to tent and heat foundations for 72 hours after placement when night time temperatures were below 35 degrees. This usually meant between October 15th through April 15th. For an average 2,000 square-feet two story house, this would cost $2,500 – $3,500 for sheet plastic, heat, and labor. It almost always means heating through the weekend, taking it down for the boom pump several times, resetting it numerous times when the wind blows it down on Sunday night or digging it out when a 12-inch snow storm buries it.

Many of us contractors did not grow up in Anchorage. I grew up in Lansing, Michigan and Paul Michelsohn grew up in New York. We both knew not all cities had such extreme requirements as Anchorage. About four years ago I called the building department in Lansing to find out that their policy is “if it is 20 degrees at 8:00 a.m., and it is scheduled to get to 21 degrees that day, you can do anything you want with no heat.” My friends say they pour when it’s even colder. That year, we put a request in the National Association of Home Builders magazine, asking people to email their local policy to us. That’s when Terry Lavy of Lavy Concrete Construction called, and we have been in contact ever since.

Our goal was to adopt a policy similar to Lansing’s, and also reduce the required tenting time when we are pouring below 21 degrees. From the beginning, we knew that guys from the CFA were pros on this subject and we should piggy back on CFA’s efforts. While waiting for the cold weather study results, Michelsohn started pumping the code review committee of the National Home Builders Association in 2002 to address this issue. Immediately after CFA’s final results were completed, Michelsohn invited CFA member Brad Barnes, of North Central Engineering LTD, to give a two hour continued education course, with the Anchorage building officials present, on December 5, 2004. Barnes kept everyone on the edge of their seats while he talked about concrete curing. Sounds impossible doesn’t it? Even the building officials were convinced. Then on January 10, 2005, Barnes attended the International Builders Show to speak to the code review committee.

“Finally, everybody’s lights went on,” stated Michelsohn.

People came up to Michelsohn and said they finally understood what he had been talking about for the past three years and they have the same problem in their area.

In February, when we finally received our CFA Cold Weather Concrete Reports, we immediately went to our building officials. We chose to pursue mixes that were in the study’s field test, since they were exposed to temperatures in the teens and lower. It was quite easy to convince the officials to allow the builders to “place Mix #29 or Mix #34 at a slump of six or less, without tenting, when the temperature at the jobsite is 20 degrees or warmer. Calcium is to be replaced with NCA.”

One hurdle we see as an issue is the resistance to pouring against cold rebar. Future studies need to address what is acceptable when rebar is used. As for now, we are thankful for the CFA’s hard work (Terry Lavy, Jim Baty, Brad Barnes, and the rest of the cold weather committee) and for keeping us informed along the way. Finally, we can pour concrete foundations in Anchorage like probably half the country always has – with cold hands.