Historic neighborhoods in Washington DC are renowned for their stately and well-preserved old brick homes. The preservation of these unique architectural and design features is paramount in maintaining the value and desirability of individual dwellings and the neighborhood as a whole. In many of DC’s historic sections, a crucial and visible maintenance chore is brick restoration and repair.
Restoring Historic DC Brick Homes
Tuckpointing, also known as "repointing," describes the meticulous restoration of historic brick buildings by removing mortar between masonry joints and replacing it with lime-based mortar. This term encompasses restoration work on both building facades and chimneys.
Lime, a construction material with centuries of history, is the fundamental ingredient in historic mortar. Its composition, texture, and level of "hardness" differ significantly from cement or concrete, modern building materials suitable for new construction.
If a historic building is repointed with cement, the extreme density of the material can cause the softer coal-fired bricks to crack. Improper tuckpointing can lead to visible signs of structural damage and interior water penetration over time.
Guidelines for Brick Restoration DC
A recommended method for tuckpointing historic brick buildings has been established based on extensive research, scientific evidence, and hands-on experience with the structures:
Comprehensive Repointing: Historic structures must be repointed entirely, addressing all exterior walls, regardless of their appearance or condition. This ensures that all issues, including gaps in mortar, harmful cement repairs, and failing brick courses, are addressed and rectified.
Skilled Masonry Crew: The work should be undertaken by a highly skilled crew of trained masons. Even a small DC row house requires a minimum crew of three, as this complex job demands careful organization and execution both on the scaffolding and on the ground.
Hand Scraping of Mortar Joints: All mortar joints, whether untouched or filled with cement, must be scraped out by hand. Some joints may need to be opened to a depth of as much as three inches to ensure proper bonding of the new mortar with the existing mortar deep inside the wall.
Use of Lime Mortar: Lime mortar is crucial for tuckpointing historic buildings. While some contractors and historic preservation agencies recommend Type N or Type O mortar, which contain mostly lime but include a small percentage of cement, the best option for historic structures is lime mortar without any cement.
Striking Mortar Joints: Restored mortar joints should be struck with a tool, creating a slight concave recess in the joint to prevent water penetration and staining on the brick wall.
Thorough Cleaning: A newly tuckpointed wall should be cleaned thoroughly with a diluted acid solution or a specially formulated masonry cleaner to remove dirt, staining, and any residual mortar left on the brick faces during the work.
Preserving Washington DC's architectural heritage demands a meticulous approach to tuckpointing, ensuring that the historic brick homes stand as testaments to the city's rich history and enduring charm. Off Limits Contractors takes pride in executing these restoration practices with precision, safeguarding the legacy of the nation's capital.