382. - Only in case of absolute necessity shall any masonry be laid in freezing weather. (See Sections 139 and 239.)

Any masonry laid in freezing weather must not be pointed until warm weather in the spring. If necessary, masonry may be laid in freezing weather, provided the stone or brick are warmed sufficiently to remove ice from the suface and the mortar is mixed with brine made as follows: Dissolve 1 pound of salt in 18 gallons of water when the temperature is at 32o F., and add 1 ounce of salt for every degree the temperature is below 300 F., or enough salt, whatever the temperature, to prevent the mortar freezing.