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19. Guide for the selection of masonry Mortars
A
TABLE 1 MORTAR TYPE:
Location Building Segment Recommended Alternative
Exterior, above grade Loadbearing wall N S or M
Non-loading wall, Parapet wall, N O
B
or S
chimney & veneer wall N S
Exterior, at or Foundation wall, retaining wall, M S
C
or N
C
below grade manholes, sewers pavements
walks and patios
Interior Loadbearing wall N S or M
Non loadbearing partitions. O N
A
This table does not provide for many specialized mortar used, such as reinforced masonry, acid resistant and re box mortars.
B
Type 0 mortar is recommended for use where the masonry is unlikely to be frozen when saturated or unlikely to be subject to high winds
or other signicant lateral loads. Type N or S mortar should be used in other cases.
C
Masonry exposed to weather in a nominally horizontal surface is extremely vulnerable to weathering. Mortar for such masonry should be
selected with due caution.
TABLE 2 MORTAR PROPORTIONS BY VOLUME
Parts by Parts by Aggregate ratio
volume of volume of (measured in
Mortar Portland hydrated damp, loose
type cement lime conditions)
M 1 1/4 Not less than 2 1/4
S 1 Over 1/4 to 1/2 and not more than 3
N 1 Over 1/2 to 1 1/4 times the sum of the
O 1 Over 1 1/4 to 2 1/2 volumes of cement
and lime used.
TABLE 3 PROPERTY SPECIFICATION REQUIREMENTS
Average compressive
strength at Water Air Aggregate ratio
Mortar 28 days, min psi retention content (measured in damp
type (MPa) min % max % loose conditions)
M 2500 (17.2) 75 12 Not less than 2 1/4 and
S 1800 (12.4) 75 12 not more than 3 1/2 times
N 750 (5.2) 75 14 the sum of the separate
O 350 (2.4) 75 14 volumes of cementitious
materials.
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