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What's Important to Know About Tuckpointing Old Brick?

Jul 18, 2017 12:42:40 PM Christina Wilson

 Historic neighborhoods in Washington DC are well known for their stately and well-preserved old brick homes. Preservation of those unique architectural and design features is essential to maintaining the value and desirability of the individual dwellings and the neighborhood. In many of DC’s historic sections, an important and visible maintenance chore is brick restoration and repair. 

Restoring Historic DC Brick Homes

Tuckpointing—or “repointing,”—describes the restoration of historic brick buildings by removing mortar between masonry joints and replacing it with lime-based mortar. This term applies to restoration work on both building facades and chimneys.

Lime, a stone used in construction for centuries, is the core ingredient in historic mortar. Its composition, texture, and strength/level of “hardness” are completely different from cement or concrete, which are modern building materials suited for new construction.

If a historic building is repointed with cement, the material’s extreme density [or its level of hardness] will cause the softer coal fired bricks to crack. If a historic building is not tuckpointed properly, it will eventually show signs of structural damage and interior water penetration.

Guidelines for Brick Restoration DC

There is a recommended method for tuckpointing historic brick buildings based on extensive research, physical/scientific evidence, and hands on experience working with the structures themselves:

  • Historic structures must be repointed in their entirety, not in sections here and there; comprehensive repair of all exterior walls, regardless of their appearance or condition, will ensure that all issues—including but not limited to gaps in mortar, harmful cement repairs, and failing/uneven brick courses--are addressed and rectified
  • The work should be completed by a highly skilled crew of trained masons; even a small DC row house requires a minimum crew of three, as this job is complicated and must be carefully organized and executed from both on the scaffolding and on the ground.
  • All mortar joints—whether untouched or filled with cement—must be scraped out by hand. Some joints will need to be opened to a depth of as many as three inches to ensure that the new mortar bonds properly with the existing mortar deep inside the wall
  • Lime mortar must be used to tuckpoint a historic building. Many contractors and some historic preservation agencies advocate the use of Type N or Type O mortar. These mixes consist mostly of lime. They are also inexpensive, easy to mix, and readily available. They do, however, contain a small percentage of cement. Lime mortar containing no cement is by far the best option for historic structures
  • 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
  • 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.

Masonry Contractors Washington DC

After decades of exposure, the mortar joints between the bricks on historic homes begin to fail.  Because of the era in which so many homes were built in Washington DC, brick restoration in these historic buildings should be trusted to masonry contractors who are specialists in the correct application of traditional materials and methods. 

Learn What To Expect During A Tuckpointing Job

 


Renaissance Development, a leader in brick restoration and historic preservation, specializes in the restoration of a historic brick building’s mortar joints using traditional methods (tuckpointing) and materials. Contact us for a free site visit and project quote.

 

Categories: Repair, Restoration

 

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