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Masonry Walls

The majority of historic buildings in the City of Lancaster are constructed with brick exterior walls. Brick is a durable building material that has been used to construct buildings in Lancaster since the 1700s. By the 1730s, there were already several local brickmakers. By 1873, there were ten brickyards in or near the City. Brick construction gained popularity in the 1870s when City regulations prohibited the construction of new wood-frame buildings to prevent fire hazards. Brick construction remained popular into the twentieth century. The development of the brick veneer process in the early 1900s allowed the look of brick masonry without the increased cost. Many rowhouses built in the 1920s and 1930s have walls of brick veneer over frame construction.

Brick has always been a fashionable construction material that gives buildings an appearance of permanence, and prominence. The visual character of brick buildings comes from the color, texture and pattern of the bricks, and the interplay with stone foundations and wood trim. The size, shape and color of the mortar joints in between the bricks also give masonry walls a unique appearance.

Even though brick is durable and long lasting, it still requires maintenance and care. With proper maintenance, masonry walls can last hundreds of years. Neglect or improper maintenance will hasten deterioration and can result in costly repairs. Using the wrong products or repair methods on masonry walls can cause severe damage.

Excess moisture in walls is the cause of most deterioration. The hard, kiln-fired outer surface of bricks helps to repel water, as does the profile of the mortar joints. The mortar between the bricks will eventually begin to deteriorate and will require repointing.

Mortar is the "glue" that holds the individual bricks together to form a wall. Over time, it is normal for mortar to deteriorate, loosen and fall away. Repointing restores the physical integrity of the wall, and the visual appeal of the building.

Sand, lime, and Portland cement are the three basic ingredients that make up mortar. Horse hair, oyster shells and ash were also sometimes added to historic mortar. The percentage of Portland cement, a minor additive to help accelerate mortar set time, should be limited. If the mortar is too hard, it can undermine the strength of the bricks by causing them to crack and break over time. Mortar should be softer than the brick in order to allow each brick unit to "move" within the mortar, as the brick walls expand and contract with seasonal changes in temperature. Too high a concentration of Portland cement will result in mortar that is excessively hard.

The use of lime mortar is recommended, as it is soft, porous, and doesn’t vary much in temperature fluctuations -- well suited to Lancaster's cold winters and hot summers. Generally, type O mortar (recipe below) is the best match for historic mortar found on most older buildings in Lancaster.

If you are not experienced in the trade, brick and other types of masonry repair and replacement is not something you should try on your own. It is best to hire a professional mason with experience in masonry restoration. Not all masons have knowledge of historic buildings, however, so don't be afraid to ask for qualifications, references, and recent examples of local work that can be viewed.

A proper repointing job will last 75 to 100 years, so it is a good long-term investment in your property!

Type O Mortar Recipe
1 part white Portland cement + 2 parts hydrated lime or lime putty + 8 or 9 parts sand of historic color