9.20.4.2.(1)

Intent 1:

To limit the probability of discontinuity in head and bed mortar joints, which could lead to inadequate tensile and compressive strength of mortar joints.

This is to limit the probability of:

• compromised structural integrity of masonry construction,
• where masonry construction is part of an environmental separator, the displacement or failure of required environmental separation elements, which could lead to deterioration, or
• in assemblies exposed to moisture or the exterior, damage and deterioration.

For floors and elements supporting floors, this is to limit the probability of excessive movement, deflection or vibration, which could lead to negative effects on the psychological well-being of persons.