HPC of South Bend and St. Joseph County - Standards Update Draft

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City of South Bend and St. Joseph County Historic Preservation Guidelines 102 For More Information: Masonry Exterior masonry includes stone, brick, terracotta, cast stone, stucco, and concrete masonry units . Historically, a building’s exterior masonry surface serves both visual and functional purposes . Visually it is an important design feature that establishes the rhythm and scale, mass and proportion of a building. Historic masonry acts as an important design feature, helping to define a building’s architectural style. It adds pattern and casts shadows on wall surfaces offering depth and definition. Functionally, historic exterior masonry typically acts as the principal load bearing system for the building, as well as its “skin”, shedding water and typically deflects sunlight and wind establishing a weather-tight enclosure. Masonry structures were historically constructed of either bricks or stones, stacked on top of each other. The individual units are bonded by mortar, which serves to hold the masonry units together and fill gaps between them. Historically the masonry was bearing, meaning it carried its own weight to the ground as well as the load of other building elements such as floors, walls, and roofs . Masonry Materials Brick Brick is by far the most common masonry material in use throughout the United States . The color of brick can vary, but red is the most common. Other common colors include yellow (buff), orange, and brown. The strength or hardness of the brick, as well as its color is determined by the chemical and mineral composition of the clay, kiln conditions, and the firing temperature used. Lake bricks, made from material dredged from lake bottoms, tend to be very soft and can be found on buildings and structures built during the nineteenth and very early twentieth centuries . Due to their softness, lake bricks are often, but not always, used to build walls that were then faced with a harder brick or covered in stucco . Dry pressed bricks are like lake bricks except the clay used was drier, leading to a harder brick which was common in the latter half of the nineteenth century and early twentieth century . Extruded bricks were popularized in the early twentieth century and are the hardest bricks, which are commonly used today . Very dry clay is forced through a form to create a long ribbon before being cut into individual units. With large-scale production it is easier to achieve higher quality control of the color and hardness . Stone Stone is a natural material which is quarried from the earth and cut according to the builder’s specifications. Historically stone walls and columns were weight bearing and constructed of individual stone units bonded with mortar . This stone was often either uniformly cut limestone or irregular granite field stone. In the mid-twentieth century, stone veneers were popularized, which are thin slabs of stone, often marble, granite, or limestone “hung” on an underlying structural support system or applied to brick masonry walls . Terracotta Terracotta is a fired clay product like brick, which is often formed into special or irregular shapes, or is a molded product with a colored glaze applied and fired onto the material. Terracotta became popular in the late nineteenth century, as it could be mass produced quickly with a high control of quality . It can be found as an accent or trim on a brick building or is sometimes used for the entire exterior . Cast Stone Cast stone is a manufactured product made form ground up natural stone, which is typically molded and re-constituted using a mixture of stone and cement, often with added coloring agents . Concrete Masonry Units (a.k.a. concrete block) Concrete masonry units (CMUs) commonly known as concrete blocks are like bricks in that they are formed structural elements . They are made by mixing water, cement, sand, and aggregate, which is placed in forms to solidify . Like brick, they are typically stacked and bonded with mortar. They are most often laid in a running-bond pattern, and should not remain exposed in historic settings, unless of an early type with a stone textured surface, not including modern split faced block . Masonry DRAFT