A picture below shows a historic brick building wall corner with damage where the wall was touched by a passing truck. The wall has also been repointed terribly by a contractor who was wholly unskilled in the practice of masonry restoration. Today’s article is a case study examining the attempts and failures in preservation and restoration leading to a poorly treated masonry building and follows the outline below:
Historic brick masonry structures should be treated like something special and unique, more than another tract home in the sea of urban sprawl just outside of our historic city center. The historic brick masonry buildings of DC are unique. They are essentially artifacts from history, limited in quantity with reducing numbers sl ost every day. They shoukd be treated as something of value. Preserving these historic brick buildings requires an understanding of history and engineering and professional restoration practices. In this today’s discussion, we will delve deeper into the science behind the dangers of using hard mortar in historic brick masonry. We will examine the principles of proper tuckpointing and explore damage mitigation strategies like bollards. Additionally, we will look at the cost-effectiveness and efficacy of skillful repointing and the challenges of removing sloppily applied mortar from fragile historic bricks. Lastly, we will discuss the architectural significance of brick infill and the distinctions between historic pressed and common bricks. The next picture below shows a closer view of the picture above at the point of damage where three bricks have been broken by a closely passing truck that merely touched the face of the bricks at the outside corner and calls those bricks to crack and break. The Use of Bollards to Protect Brick Facades in Tight AlleywaysHistoric brick facades, especially at corners and in narrow alleyways, are susceptible to damage caused by vehicular impact. The forces exerted by vehicles during collision events can lead to catastrophic structural failure and compromise the safety of pedestrians and occupants, we have seen a few extreme examples right here in Capitol Hill. Bollards are an option, in some cases, designed to mitigate this risk by providing a physical barrier against vehicle impact. Bollards, when properly installed, function as force-absorbing barriers that dissipate impact forces and prevent direct contact with the brick facade. They distribute the forces over a larger area, even into the cantilevered concrete footing reducing localized stresses on the brickwork. By selecting appropriate bollard materials, such as steel tubing in combination with reinforced concrete, bollards are durable and often effective in protecting the historic brick masonry. The Dangers of Using Hard Mortar in Historic Brick MasonryIn the in addition to the damage caused by impact from a vehicle, the wall has also been very sloppy repointed using the wrong type of mortar. it’s extremely important to use a proper historic lime mortar when repointing historic brick and masonry facades. Some untrained contractor used a Portland cement mortar, at the wall shown here, the type bought off-the-shelf at a big box store. Big box stores unfortunately don’t sell the type of mortar required to repoint and restore historic masonry. Even right here in Washington DC, we have two large big box stores selling the type of mortar that can’t be used on the historic buildings of Washington DC, Realtors and property managers throughout the city, trying to make a quick buck, will often send their unskilled laborers out to purchase this incorrect type of cement and use the resulting mortar incorrectly to point up brick facade walls like the one shown in the photos below. Historic brick masonry was designed to withstand the forces of time and the environment. Traditional bricks were softer and more porous than modern bricks. Using hard cement-based mortars with these delicate bricks creates a mismatch in material properties. Hard mortars lack the flexibility required to accommodate the natural expansion and contraction of historic bricks due to temperature variations. This inflexibility leads to differential movement between the bricks and the mortar, resulting in internal stress, cracking, and spalling. Modern Portland cement-based mortars are rigid and non-porous, which inhibits the bricks’ ability to “breathe” and release moisture. This trapped moisture can freeze and expand during colder temperatures, causing micro-cracks and further weakening the brickwork. In contrast, historic lime-based mortars are more compatible with the softer bricks, providing the necessary breathability, flexibility, and self-healing properties. The next picture below shows the damage brick from an even closer angle. From this perspective you can see the original motor at the area where the bricks were broken. The new motor has been smeared on top of the face of the bricks and on top of even the damaged area of mortar, overlaying the top of the brick joint. After having worked with brick and mortar for decades, it’s hard to imagine how someone can even do this type of work where it looks so bad. Even when training new machinery apprentit’s in the beginning, right when they start, they can generally do a much better job than this. Why Proper Tuckpointing is ImportantTuckpointing is an essential restoration process that involves replacing deteriorated mortar joints with compatible materials. Decades of time can elapse between repointing iterations if the work is done properly. The primary objective is to maintain the structural integrity, restoring moisture resistance properties, and simultaneously enhancing its visual appeal. Proper tuckpointing minimizes water infiltration, which can accelerate the decay of historic bricks and weaken the building’s overall stability. Historic masonry structures are subjected to various environmental stresses, including moisture, temperature fluctuations, and air pollutants transferred to buildings by acidic rain. When the mortar joints start to deteriorate, water can seep into the brickwork, compromising its strength and promoting the growth of destructive microorganisms, often referred to in the preservation discipline as biocolonization,like algae and fungi. The appropriate choice of mortar type, such as lime-based mortars, ensures compatibility with the historic bricks, facilitating better adhesion and allowing for the desired flexibility. It’s cheaper to do it right the first timeRepointing is a restoration process where damaged or deteriorated mortar joints are replaced. It is essential to use skilled contractors, like IDS, who understands the principles of historic masonry restoration to ensure that the new mortar is historically compatible with the specific historic bricks of each particular facade of a building. A successful repointing process improves the overall structural stability, resistance to the elements, and longevity of the building. The success of repointing lies in the careful selection of compatible proper substrate and subcomponent materials and the proper application of repointing processes. An understanding of the properties of both the historic bricks and the mortar is crucial. Lime-based mortars, with their lower compressive strength and higher permeability, allow the historic bricks to maintain their breathability and accommodate moisture movement, reducing the risk of frictional damage. The picture below shows a close up view of the improper motor used in the repointing of a historic building. The motor is smeared all over the face of the historic brick in a slapdash sort of mess. A once beautiful historic building now looks just like a type of thrown up collection of salvaged garbage. In this sloppy state it couldn’t even accidentally be mistaken for a German smear effect. Challenges of Removing Sloppily Applied Mortar from Historic BrickSloppily applied mortar is a common issue in the restoration of historic brick masonry. Aggressive removal methods, such as sandblasting or mechanical grinders, can cause significant damage to the fragile historic bricks. Preserving the unique texture and character of historic bricks requires a scientific approach to identify suitable removal techniques. Historic bricks are more porous and softer than modern bricks. The abrasive force of sandblasting or mechanical grinders will invariably erode the brick’s facing surface, resulting in further damage and increased susceptibility to moisture absorption. A thorough examination of the historic bricks’ physical properties and a thorough understanding of the compatibility of mortar removal methods are necessary before even attempting cleaning. This type of damage is significant, yet can happen so quickly from using an untrained contractor. In some cases, using non-abrasive removal techniques, such as chemical poultices and low-pressure water wash, the restoration can partially remove the slapdash mess of mortar, but the efficacy of this type of tedious process is limited and extremely costly. Brick Infill When Doors or Windows are Removed from Building FacadesAs historic buildings undergo adaptive reuse, there may be a need to remove doors or windows. Brick infill is a restoration practice employed to maintain the building’s visual cohesiveness and structural stability. Engineering principles are crucial in selecting the appropriate bricks, mortar, and infill design to ensure a seamless integration with the existing brickwork. Removing doors or windows leaves gaps in the brick facade, which, if not properly addressed, can compromise the building’s integrity and thermal performance. Carefully matched bricks and compatible lime-based mortars are essential to create a uniform appearance and maintain structural integrity. Historic Pressed Bricks vs. Historic Common BricksHistoric brick masonry encompasses various brick types, each with its own unique characteristics and properties. Understanding the distinctions between historic pressed bricks and historic common bricks is essential for proper restoration and repair practices. Historic pressed bricks are manufactured by pressing clay into molds, resulting in a uniform and smoother surface finish. The uniformity of pressed bricks makes them ideal for facing and providing a more refined and elegant appearance to the building’s exterior. On the other hand, historic common bricks are made by hand, leading to a more irregular texture. These bricks are typically used in the building’s core, where their rougher texture may not be visible but still contributes to the overall structural strength. Understanding the differences between historic pressed bricks and historic common bricks empowers restoration professionals to make informed choices when sourcing materials and ensuring the authentic preservation of these remarkable architectural treasures for future generations to appreciate and cherish. Through the thoughtful application of architectural engineering and scientific restoration practices, we can safeguard these historic gems and continue to celebrate their cultural and historical importance for many years to come. Preserving historic brick masonry requires a scientific approach that draws on professional restoration principles and practices. Understanding the risks associated with hard mortar, the significance of proper tuckpointing, and the importance of protective measures like bollards is crucial in maintaining these valuable cultural heritage structures. By embracing the scientific reasoning behind material compatibility and the importance of skilled craftsmanship, contractors like IDS can successfully repoint historic brick masonry structures, ensuring their longevity and visual appeal. Moreover, the insidious damage caused by sloppily applied mortar can be so extreme that it can exponentially damage a building. Historic masonry upkeep and preservationTo properly maintain, repair, and care for these historic buildings, a knowledge, interest and understanding of historic building principles is required. Here in Washington DC, historic masonry buildings are extremely expensive and the amount of financial loss caused by improper repointing and low quality construction is staggering. However, in addition to the direct financial value of the property, there is also a cultural loss when historic buildings are damaged. By comparison, consider neighboring poor cities, when historic buildings are damaged, it’s not just the loss of value to the property owner, there’s also a loss to all inhabitants and visitors of a city, present and future, who care about architecture, history, and culture. We encourage all of our clients, and all readers of this article and to our blog in general, to prioritize the historic built environment of Washington DC and neighborhoods such as Capitol Hill, Dupont Circle, and Georgetown and become educated on on the difference between proper historic preservation versus improper work which leads to significant damage to the historic fabric of a building. From a conservation and preservation perspective, several approaches can be taken to improve conditions related to deteriorated historic brick masonry. Primarily, lime mortar brick joints and low temperature fired soft red clay bricks should be inspected and checked on a routine maintenance schedule, either seasonally or at least annually. If brick masonry is kept in good condition, the life of embedded wood elements can be significantly extended. Hire a professional contractor which specializes, understands and appreciates historic construction elements and buildings. You can learn a lot more on our blog. Feel free to check it out. If you have questions about the historic masonry of your building in Washington DC, contact us or fill out the webform below and drop us a line. We will be in touch if we can help. <p>The post Brick Pointing And Pressed Bricks Case Study first appeared on Infinity Design Solutions.</p> Via https://www.ids-dmv.com/masonry/brick-pointing-and-pressed-bricks-case-study/
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About UsInfinity Design Solutions LLC (IDS) is a full service general contracting company in the heart of the Dupont Circle neighborhood of Washington, DC. We focus on repair and renovation of buildings and facilities in both historic designated neighborhoods and the commercial-zoned central business district of the city. Follow Us
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