(A) Proportions. Mortars of the following proportions measured by volume with sand in a damp, loose condition shall be acceptable for the specific uses mentioned in this section:
(1) Type A. One part of portland cement to not more than three parts of sand with an addition of hydrated lime or lime putty or not more than 25% of the cement;
(2) Type B. One part of portland cement, one part of hydrated lime or lime putty, and not more than six parts of sand; or one part of prepared masonry cement conforming to Federal Specifications, Type 11 (U.S. Bureau of Standards) FS-C 181B to not more than three parts of sand.
(B) Use. Type A mortar shall be used for all below grade masonry construction. Type A or Type B mortar shall be used for all above grade construction.
(1990 Code, § 8.7)