Mortar Types
 Type  Strength (psi)  Mixture (by volume)
 K  75 2 lime + 5 sand or
3 lime +1 cement +10 sand
 O  350 2 lime + 1 cement + 5 sand
 N  750 1 lime + 1 cement + 5 sand
 S  1800 1 lime + 2 cement + 4 sand
 M  2500 1 lime + 4 cement + 16 sand

Mortar Applications
 Masony material  Sheltered
exposure
 Moderate
exposure
 Severe
exposure
Very durable
hard brick, granite
 O  N  S
Moderately durable
most brick, limestone
 K  O  N
Poorly durable
soft brick, friable stone
 lime & sand  K  O

Lime and sand mortar, 1842, Wheeler House, Burlington, VT


UVM Historic Preservation Program