Hot & Cold Weather Masonry Construction

Recommendations

Cold weather masonry construction and its quality control require some additional attention to construction practices and protection. Attention should be directed to the following details as well as those normally attended.

1. Implement the cold weather construction and protection requirements of this recommended practice when temperatures are forecast to fall below 40°F (4.4°C) or the temperature of the masonry units is 40°F (4.4°C) or lower. Check local weather reports before the start of each day and periodically measure air temperature during the day.

2. Receive, store, and protect construction materials in ways that prevent water from entering the materials.

3. Measure temperatures of construction materials when climatic conditions warrant. Thaw frozen sand and wet masonry units. Heat masonry units that are at or below 20°F (-6.7°C) without overheating.

4. Heat sufficient ingredients to produce mortar and grout temperatures between 40°F (4.4°C) and 120°F (48.9°C). Produce consecutive batches with nearly the same temperature. The mortar temperature after mixing and before use is required to be above 40°F (4.4°C), maintainable either by auxiliary heaters under the mortar board or by more frequent mixing of mortar batches. Heated mortar on mortar boards must not become excessively hot (greater than 120°F; 48.9°C).

5. During below normal temperatures, place masonry only on sound unfrozen foundations. Never place masonry on a snow or ice covered surface, because of the danger of movement when the base thaws and the possibility of very little bond being developed between the mortar and the supporting surface.

6. At the end of the day, protect the top surfaces of all masonry to prevent moisture, as rain, snow, or sleet, from entering the masonry. Cover the top surfaces such that the protection extends down a minimum of 2 feet (0.6 m) down all sides of the masonry.

7. Do not lay glass unit masonry when the ambient temperature falls below 40°F (4.4°C) or the temperature of the units is below 40°F (4.4°C).

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