Masonry Magazine July 1979 Page. 19
d. Hold cover securely in place.
2. Load application:
a. Do not apply uniform floor or roof loading for at least 12 hr. after building masonry columns or walls.
b. Do not apply concentrated loads for at least 3 days after building masonry columns or walls.
B. Staining:
1. Prevent grout or mortar from staining the face of masonry to be left exposed or painted:
a. Remove immediately grout or mortar in contact with face of such masonry.
b. Protect all sills, ledges and projections from droppings of mortar, protect door jambs and corners from damage during construction.
C. Cold Weather Protection:
1. Preparation:
a. If ice or snow has formed on masonry bed, remove by carefully applying heat until top surface is dry to the touch.
b. Remove all masonry deemed frozen or damaged.
2. Products:
a. When brick suction exceeds recommendations of Section 1.03.B.3, sprinkle with heated water:
(1) When units are above 32° F. (0° C.), heat water above 70° F. (21° C.).
(2) When units are below 32° F. (0° C.), heat water above 130° F. (54° C.).
b. Use dry masonry units
c. Do not use wet or frozen units.
3. Construction requirements while work is progressing:
a. Air temperature 40° F. (4° C.) to 32° F. (0° C.):
(1) Heat sand or mixing water to produce mortar temperatures between 40° F. (4° C.) and 120° F. (49° C.).
b. Air temperature 32° F. (0° C.) to 25° F. (-4°C.):
(1) Heat sand and mixing water to produce mortar temperatures between 40° F. (4° C.) and 120° F. (49° C.).
(2) Maintain temperatures of mortar on boards above freezing.
c. Air temperatures 25° F. (-4° C.) to 20° F. (-7° C.):
(1) Heat sand and mixing water to produce mortar temperatures between 40° F. (4° C.) and 120° F. (49° C.).
(2) Maintain mortar temperatures on boards above freezing.
(3) Use salamanders or other heat sources on both sides of walls under construction.
(4) Use windbreaks when wind is in excess of 15 mph.
d. Air temperature 20° F. (-7° C.) and below:
(1) Heat sand and mixing water to produce mortar temperatures between 40° F. (4° C.) and 120° F. (49° C.).
(2) Provide enclosures and auxiliary heat to maintain air temperature above 32° F. (0° C.).
(3) Minimum temperature of units when laid: 20° F. (-7° C.).
4. Protection requirements for completed masonry and masonry not being worked on:
a. Mean daily air temperature 40° F. (4° C.) to 32° F. (0° C.):
(1) Protect masonry from rain or snow for 24 hr. by covering with weather-resistive membrane.
b. Mean daily air temperature 32° F. (0° C.) to 25° F. (-4° C.):
1.05.C.3 Ideal mortar temperature is 70° F. ± 10° F. (21°C. ± 6° C.). The mixing temperature should be maintained within 10° F. (6°C.).
1.05.C.4 The following options may be used in cold weather construction:
1. Change to a higher type of mortar required in ASTM C 270. (Example: If ASTM type N mortar is specified for normal temperature, change to type S or type M.)