Dictionary of Moisture Protection & Restoration

Guide for the Selection of Masonry Mortars Exterior, above grade Load-bearing wall Recommended mortar Type N Alternative mortar Type S or M

Exterior, above grade Non-load bearing wall Recommended mortar Alternative mortar Parapet wall Recommended mortar

Type O ♦ Type N or S

Type N Type S

Alternative

Exterior at or below grade Foundation, retaining wall, manholes, sewers, pavements, walks, and patios Recommended mortar

Type S ♥

Type M or N ♥

Alternative mortars Interior Load-bearing wall Recommended mortar Alternative mortars Non-bearing partitions Recommended mortar Alternative mortar

Type N

Type S or M

Type O Type N

♦ Type O 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 significant lateral loads. Type N or S mortar should be used in other cases. ♥ Masonry exposed to weather in a nominally horizontal surface is very vulnerable to weathering. Mortar for such masonry should be selected with due caution.

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