As much as contractors would like to avoid working with temperature sensitive materials in the winter, tight schedules or project delays can make that a challenge. Special considerations have to be made in the winter months in order to make sure block walls have a high quality installation and workers are kept safe while doing it.
Recently, Masonry Magazine published an interview with two masonry contractors, who explained how they deal with the challenges of working in cold weather. This information could not only be interesting to other masonry contactors, but also general superintendents and project managers, who are ultimately responsible for ensuring the structure meets the contract’s requirements.
The two interviewees are Austin Norberg of Seedorff Masonry Inc., and Paul Cantarella Jr. of Cantarella & Son Inc. The biggest challenge in cold weather masonry construction, they say, is keeping the materials, especially the block and mortar, at a proper and consistent temperature. Masonry contractors are able to find specific temperature requirements in the ACI 530 code, but, in general, Norberg states that masonry units should be kept above 20°F and mortar and grout should be between 40-120°F.
Keeping consistent temperature on the mortar allows for consistent dry time before jointing. Temperature becomes especially important with colored mortars, says Cantarella, because different temperatures could cause a variability of color throughout the wall.
Enclosed Scaffolding and Mixing Areas
Covering the scaffolding helps keep consistent temperatures during install and to keep the masons warm, but it presents distinct safety challenges, as well. The covering material can turn the scaffold into a sail in moderate to high wind situations, so securing the scaffolding is an extremely important extra step to be considered.
If heaters are being used inside an enclosed area, air quality must be monitored, as well. Cantarella & Sons typically installs corrugated pipe under the sand in their mixing shanties and heats them up with a torch heater. Because of that, they make sure to install carbon dioxide detectors and thermometers. Cantaella also mentions some new technologies that are available, like electric water heaters and sand heaters.
Other Factors to Consider
You can’t only think about keeping your building materials warm, you also have to think about the tools and containers being used. Water hoses should be kept from being frozen for productivity reasons, battery powered tools could perform less efficiently if allowed to freeze, and frozen mortar tubs can affect mortar workability.
Norberg also mentions that inspectors should be made aware that material samples should be kept in an area consistent with where the sample was taken from. “Samples stored at the base of a shelter may not cure out the same as the work being completed 20’-30’ above if measures aren’t taken to keep similar temperature. Inconsistent test reports can lead to additional testing or rework to confirm the masonry meets the design requirements,” he told Masonry Magazine.
I encourage you all to read the full article from Masonry Magazine, it has some additional information, not covered here, that could prove useful to you.
What other precautions do you take on your jobsites in the winter months? Tell us in the comments below!
Full story: Cold Weather Block Construction: A Sit Down with Two Contractors | Masonry Magazine