A. Portland cement mortar used in laying up masonry shall be mixed in the proportion of one part of Portland cement to not more than three (3) parts of sand, by volume. Hydrated lime or lime putty may be added not to exceed fifteen percent (15%) by volume of the Portland cement.
B. Cement-lime mortar shall be mixed in the proportion of one part or hydrated lime or lime putty to not more than six (6) parts of sand by volume.
C. Lime mortar shall be mixed in the proportions of one part of Portland cement added to the amount of fifteen percent (15%) of the volume of the lime. (1964 Code § 290)