Masonry Magazine October 1994 Page. 33
HOT WEATHER CONSTRUCTION PROCEDURES
Code Requirements:
Ambient air temperature exceeds:
100 F, or
90 F with wind velocity greater than 8 mph
Mortar bed less than 4 feet ahead of unit bedment,
Set units within one minute after laying bed.
Hot Weather temperature included in Project Specification
Master Plan for hot weather masonry construction:
Rescheduling workday hours.
Schedule masonry construction to working face orientation, i.e., N,S,E,W.
Mortar production in weather protected enclosure.
Provisions made for cooling sand, water, and mixer.
Provisions made for maintaining mortar cool on mortar board.
Provisions for maintaining masonry moist:
Relative humidity initiating action,
Vapor barrier covering of wall,
Moist spray at end of work day for "x" days, including non-work days.
Other
Heated during the early stages after grouting. Every protective measure should be taken to avoid the freezing of the grout until the water content of the grout is sufficiently low that disruptive expansion will not occur.
Because grouted masonry can couple clay units with concrete masonry units both with an array of absorption characteristics, it is difficult or impossible to predict the period before freezing will occur. Thus, grouted masonry should be overly protected with heat and coves provided. Failure to maintain the grout above freezing can result in disruptive expansion, as evidenced by splitting of the CMU face shell or misalignment of units.
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Summary
Both hot and cold weather masonry construction can and should continue during these other than normal weather conditions. The masonry contractor should be allowed to and should modify the masonry construction procedures to compensate for weather effects. The masonry contractor's decisions will be based on equipment already available, possible rentals, and other options available for the production of quality masonry. It should be understood that masonry constructed during both cold and hot weather periods has a greater tendency toward evidencing efflorescence. The appearance of efflorescence signifies less than optimum curing conditions, thus curing and cleansing remedial action may be required.
ALBERT W. ISBERNER, a consulting materials engineer is a fellow in the American Society for Testing and Materials and the American Concrete Institute. He's also a member of the Construction Specifications Society for Ter Institute and the Masonry Society. A registered Professional Engineer in Wisconsin, he has written numerous articles in the field.
PRESERVATION PLAN ON IT
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