Besides the fact that you should have your brick fireplace up and burning by now, there are more things to consider in masonry when these winter months are upon us.
As the construction industry fights back from the recession, contractors may not want to stop large construction (or small for that matter) projects because of a little cold weather or snowstorm.
Brick masonry can be laid in virtually in any weather conditions –with the right preparation, and treatments. To ensure the quality of masonry construction there are mandatory building codes to follow. Contractors and masons must be well-prepared and have thoughtfully planned ahead so they can implement their best quality control efforts with dropping temperatures.
Units may not be laid if they have a temperature under 20° Fahrenheit or have ice or snow on them. So, if brick is being left on a job site, the units must be properly stored with tarpaulins or polyethylene sheets, and free from any water drainage. Heating the brick, even if they are above 20°F may be a good idea prior to laying as it helps with minimize the effects of cold weather on mortar hydration.
Cold materials used to mix mortar create different properties that cause reduced early strength (lower water content, increase air). As displayed in the chart above, if temperatures are below 40°F you must heat the sand or mixing water to temps between 40-120°F. Ideal temps are between 60-80°F. Water is the easiest material to heat.
The process of hydration of cement continues over an extended time developing the strength of the bond in masonry. Newly constructed masonry must take protective measures. If the temperature drops below 40°F it must be covered with a weather-resistive membrane for 24 hours. If the temp is 20-25° you must use insulated blankets and if it is below 20°F you must heat the enclosure to 32°F for 24 hours.
Last winter, during the construction of Exempla Saint Joseph’s Hospital in Denver, Summit Brick Company’s St Joseph’s blend had to be enclosed and heated as they worked through the cold days. Masonry contractors will enclose sections at a time and often, scaffold companies will have enclosures that work for covering a newly constructed section at a time.
As freezing temperatures creep in, it is important that everyone involved in a project can plan accordingly. Following provided guidelines will help ensure proper quality construction of masonry in winter weather.