A large, three-story brick building on a modern city street

Historic bricks are defined by their age, unique characteristics, and the traditional methods used in their creation. Unlike modern bricks, which are often uniform and mass-produced, historic bricks typically vary in size, shape, and color. These variations are reflective of the regional materials used in brick construction and period-specific techniques.

While old, damaged bricks can be restored, the approach is different from a standard restoration project. In historic brick restoration projects, the emphasis is always on preservation—maintaining originality and authenticity should always be the goal.

In this article, we’ll discuss the nuances of restoring old brick and provide considerations and basic tips for this type of project.

*An important note: attempting restoration projects in winter, especially at or near freezing temperatures, is inadvisable because the brick may sustain even more damage during restoration.

Perform a Site Assessment & Research the Building’s History

The first step in a historic restoration process is always conducting a thorough site assessment and researching the history of the building.

Understanding the building’s condition is crucial, as other structural or environmental issues, like foundational instability or extensive water damage, may need to be addressed before the restoration project can begin.

Researching the building’s history is equally important. As mentioned earlier, preservation is the primary goal of historic restoration, so it’s important to understand the type of brick the building is constructed from and how it was constructed. Materials and techniques vary significantly over time and regions. Historic bricks might include handmade clay bricks or sand-lime bricks, and building techniques could range from traditional English bond to Flemish bond. Knowing these nuances is critical to respecting the building’s historical integrity. In fact, under the National Historic Landmarks program, the federal, local, or state governments can withdraw a landmark’s historic designation if its historic qualities are significantly altered or damaged. So, planning is not a step that can be skipped.

Determine If Replacements Are Needed

After performing a site assessment and researching the building’s historic qualities, the next step is determining if brick replacements are needed.

The guiding principle is to repair rather than replace to preserve the original materials that make the building historic. Replacing bricks should be considered only when absolutely necessary, such as in cases of severe deterioration that cannot be remedied through repairs.

Signs That a Replacement Is Needed

When assessing the condition of bricks, look for signs of significant damage, like deep cracks, spalling, or bricks that have become extremely porous. Minor cracks and weathering often add to the historic charm and can be repaired rather than replaced.

How to Handle Replacements

If brick replacement is unavoidable, matching the new bricks as closely as possible to the originals is vital. This includes mimicking the size, shape, color, texture, and material composition. Historic bricks were often made locally, with variations in color and texture depending on the local clay used and the firing process. Finding a close match might require sourcing from specialized suppliers or manufacturers who can create custom bricks. If sourcing original bricks is not feasible, replicas that closely resemble the original in all aspects should be used.

Additionally, the mortar used in the restoration should be compatible with historic masonry. Old mortar was typically softer and more porous than modern mortar, so using a modern, harder mortar can cause damage to the original bricks. In addition to analyzing the brick, it’s essential to analyze the original mortar and replicate its composition, strength, color, and texture as closely as possible.

Remember—every effort should be made to maintain the original character of the historic building.

Carefully Clean the Bricks

A man, wearing gloves, uses a red, stiff-bristled brush to remove white efflorescence from the joints and surface of brick.

In many cases, a thorough cleaning may be all that’s needed to restore historic bricks, as cleaning can significantly restore some of the masonry’s original color and character.

One of the primary rules of cleaning historic bricks is to avoid power washing. High-pressure water can be too harsh and potentially erode the brick surface and mortar joints. Similarly, sandblasting is not advisable as it can permanently damage the brick’s surface, stripping away its historic character and protective fire-skin.

In general, avoid abrasive cleaning methods and use a gentler approach. Before cleaning, always conduct a patch test on a small, inconspicuous area before cleaning the entire surface to assess the effectiveness of that particular cleaning method.

For the cleaning solution, always use non-acidic detergents, like a mild soap solution. Using harsh chemicals can damage the bricks and mortar. Gentle and careful hand washing is recommended—using natural bristle brushes is fine, but avoid metal bristle brushes or Brillo pads because they will be too abrasive for old brick. The goal is not to make the brick look new but to reveal and preserve its aged beauty.

Repoint Damaged or Cracked Mortar

An outdoor brickwall with several cracks running through the mortar

Repointing, the process of renewing the external part of mortar joints, is sometimes necessary in historic brick restoration projects when dealing with damaged or cracked mortar. This process should be approached with caution and only done when the mortar is missing entirely, visibly cracked, or disintegrating.

When removing loose or damaged mortar, use a hand rack, which will allow you to carefully remove the mortar without damaging the surrounding brickwork. Power tools are generally discouraged because they can easily damage historic bricks.

Advice on Mortar

As we covered earlier, selecting the right mortar is also crucial and should match the historic mortar in type, color, texture, and compressive strength. This often means creating a custom mix.

Notably, the mortar used for repointing should be softer than the existing brick. This ensures the mortar, rather than the brick, will bear the brunt of any environmental wear and protect the integrity of the bricks. Using a mortar that is too hard or strong for the bricks can lead to accelerated deterioration of the bricks themselves because harder mortar forces the bricks to absorb more moisture and environmental stress, leading to cracking and damage.

Furthermore, it’s essential to replicate the original width and profile of the mortar joints. This attention to detail ensures the repointing work blends seamlessly with the original masonry, preserving the historical appearance of the building.

Finally, don’t use synthetic caulking when repointing historic brickwork. Synthetic caulking does not have the same properties as traditional mortar and can cause long-term damage to the bricks.

Repair Deteriorating Brick

A severely damaged brick wall. There is white efflorescence on some of the bricks and a few of the bricks are broken or missing

Water damage is a common issue in older masonry. When repairing this type of brick damage, it’s important to avoid waterproofing or water-repellant coatings. These modern solutions can actually trap moisture inside the bricks, leading to further issues like spalling or efflorescence.

Using stucco or cement to patch historic bricks is also not advisable. These materials can be significantly harder and less porous than original bricks and mortar. Using them for patching can lead to a mismatch in physical properties, potentially causing more harm than good to the historic masonry. Stucco and cement patches also create stress points in the brickwork and prevent proper moisture evaporation, exacerbating existing issues.

Repairs should always be made using materials compatible with the original masonry.

Get Help With Your Historic Restoration Project

Many things can go wrong in a historic brick restoration project. That’s why it’s recommended to work with a masonry specialist.

Historic projects require the ability to thoroughly and carefully assess a building’s condition while respecting its historical significance. A masonry specialist with experience handling historic projects understands the importance of preservation and can help you source replacement brick, restore faded color, and perform repointing as needed, all while remaining compliant with federal, state, and local rules and regulations.

If you need help with your restoration project, contact All Brick. We’re a family-owned and -operated masonry company specializing in brick paver projects, including restorations, repairs, and installations.

Contact us today to learn more about our capabilities and past projects or request a project consultation.

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