Mortar Additive for Residential Masonry

Mortar Additive for Residential Masonry block brick stone work

Cement is one ingredient that goes into mixing mortar for residential masonry work, complementing other ingredients like water, lime, and sand. Cement also comprises multiple ingredients, including silica, magnesium oxide, calcium oxide, and others. In addition to the foundational ingredients, cement may contain certain additives to enhance certain properties for use in mortar and masonry. In masonry, construction often uses lime mortar that may contain pozzolans (i.e. supplemental cementitious material) such as mineral slag, calcined clay products, and sands. 

Mortar may also use a variety of mortar admixtures that further improve construction, with different admixtures working for various structures ranging from structural construction to facades.

Mortar Admixture Types (ASTM)

The American Society for Testing and Materials (ASTM), now known as ASTM International, lists all recognized mortar admixtures. 

The many mortar admixtures specified under standard ASTM C1384-18e1 include:

• Bond enhancers
• Set retarders
• Set accelerators
• Workability enhancers
• Water repellent

These admixtures offer numerous advantages that can improve masonry work, including increased strength, increased workability, reduced efflorescence, and reduced water absorption.

Building with Bricks

Many facades and structures featuring brickwork use Type M mortar. Type M mortar contains a large amount of Portland cement, is the most popular cement mixture and offers sufficient strength. Brickwork often uses lime mortar because of its benefits, such as reduced shrinkage and better workability. Meanwhile, below-grade elements such as brick paths may use Type S mortar.

Regarding mortar joints, brick walls typically feature flush joints, which remain flush to the wall to form a monolithic appearance in many applications.

Building with Stone

Stone residential masonry work often uses Type N mortar that features a unique mixture of one part Portland cement, one part lime, and six parts sand. It may contribute to soft stone masonry work such as limestone, along with stone veneer construction. Some applications could also use Type M mortar that features a strength similar to that of stone.

Stone masonry most frequently uses standard raked mortar joints. These joints are about half an inch wide and sink into the crevices between stones to form a deeper recess, helping the stone to stick out.

Building with Blocks

Concrete block masonry work may use either Type M, N, or S mortar for everything from walls and other facades to structural elements such as foundations and retaining walls.

Beaded joints and overgrout mortar joints both lend an old- world appearance that may appeal to homeowners, as they use thick layers of mortar that stick out.

Choose the Most Appropriate Admixtures for Residential Masonry Work

Based on the materials used for mortar cement for brick, stone, or blocks, you can select different mortar admixtures to enhance the final results. The right admixtures can add strength, workability, durability, and water-resistance, among other properties that increase the reliability and longevity of residential masonry construction.