The most destructive factor for mortar joints is freeze–thaw cycling: absorbed moisture expands
upon freezing (~9% volume increase), creating internal stresses that crack mortar and spall joints.
A: Wind loading affects wall stability, not directly mortar joint durability.
B: Control joints manage thermal/movement cracks but aren’t the main durability factor.
C: Efflorescence is cosmetic and less destructive than freeze–thaw action.
PDD Reference: Masonry durability—Moisture management; ASTM C270 Mortar Specs; ARE 5.0 PDD
“Building envelope durability in cold climates.”
