Entropy and decay are natural, part of deterioration of historic buildings but when managed proactively masonry facades can be effectively preserved

This image shows the significantly deteriorated rear masonry facade of urban rowhomes with a rear projecting cantilever at the the top floor. The cantilever was an element found in both of the buildings in the center of the image. The projecting cantilever has already collapsed at the building left of center. It looks poised and ready to collapse at the right side as well. If you look closely, you can see the openings, like beam pockets found at typical interior floor joist bearing points, left in the exterior brick masonry wall to allow the cantilevered floor joists to pass through. Entropy and deterioration happens in a nonlinear manner, increasing at an increasing rate.

The outline of today’s article follows below:

Table of Contents

Overview of entropy in masonry facades

Today’s article explores the effects of decay and entropy on historic masonry facades, the factors contributing to their deterioration, and preservation strategies to safeguard these valuable historic assets. Entropy in historic masonry facades refers to the natural process of decay and degradation that occurs over time in these structures. Masonry facades, which are typically composed of brick, stone, or other types of masonry materials, are subject to various environmental and human-induced factors that contribute to their deterioration. In the image above you scan see this extreme deterioration that has happen to the rear facade of the building without care and upkeep.

The picture above shows a small section of a rear masonry facade in CapitolHill, Washington, DC, in great need of masonry restoration, including proper tuckpointing and orvrepointing with a carefully historically accurate mortar.

The concept of entropy in this context is derived from thermodynamics, where it signifies the tendency of a system to naturally move towards a state of disorder or randomness, in almost all types of buildings and building systems. In the case of historic masonry facades, entropy manifests as the gradual loss of structural integrity, appearance, and functionality of the building’s outer wall assemblies. These natural forces of entropy are happening sll around us, all the time, to buildings and materials. Buildings require trained and skilled care and upkeep to be preserved and resist the forces of nature to return back to dust.

Several factors contribute to the entropy of historic masonry facades:

Weathering
Pollution / climate
Bioconalization
Poor maintenance
Unskilled contractors
Structural failures

We’ll discuss further details about the items in the list above, but first we’ll explain the layout and some elements of the anatomy of historic masonry facades.

Understanding Historic Masonry Facades

The historic brick masonry buildings in Washington DC, constructed over a century ago, exhibit a remarkable architectural composition comprising several key elements, some of which are described below.

Brick Masonry

These buildings feature load-bearing brick walls, where bricks were arranged using lime-based mortar, creating a relatively durable facade. You can see near endless brick buildings in the historic neighborhoods of Washington, DC, over 100 years old, with historic brick facades. The brick has lasted well, but is still susceptible to damage from moisture, freeze-thaw cycles, and low temperature firing related failures.

Window Sills

Located beneath windows, window sills are most commonly built of ashlar carved stone and serve to direct water away from the facade, protecting against moisture infiltration by creating both a monolithic or continuous cap over the masonry wall below, made of smaller individual units of brick, in most cases, and also creating a projection which extends a bit beyond the facade. This projection allows water to run off tgecedge of the sill and fall beyond the face of the facade instead of running down the facade. This passive protection allows tge facade to stay much drier during through the majority of rain events.

Varied Architectural Details

Historic masonry facades often incorporate decorative elements like “freizes”, “quoins,” “pilasters,” and “reliefs,” enhancing the aesthetic appeal and representing specific architectural styles.

Cornices

Ornamental projections along the roofline, usually made of metal or detailed brick patterns, or sometimes even made of wood in Capitol Hill and other DC historic neighborhoods, adding architectural elegance while also shielding the lower facade against repeated water pathways at non-wind-driven events of precipitation.

Parapets

These low walls extend above the roofline, functioning as a demarcation and separation between row or conjoined building’s individual roof systems and supporting coping to prevent water entry. They are mostly unseen from the ground, but at facades without mansards, a parapet is often seen at the top of the facade.

Flashing and terminations

Installed at junctions, flashings are a common component which divert water away from vulnerable areas, preventing water intrusion and or water pathways down the face of building facades. In historic times, flashing metals were often fairest alloys. Today, particular maintenance and upkeep is required to prevent Ferris metals from rust and corrosion. New roof systems, for example, in most cases are added to the top of the building but terminated above the front facades with a aluminum or TPO coated aluminum pre-bent metal flashing or drip edge.

Brick Chimneys lined with terracotta flues

Constructed using bricks, chimneys facilitated ventilation and provide a pathway for smoke from interior spaces. In many cases the original fireplaces have been abandoned or sealed off left in a state or defunct encapsulation. In some cases fireplaces have had decorative panels added to seal off the front openings, both to limit drafts from the chimney cavity and keep rodents out. In modern times most houses have had HVAC or boiler heating systems added to the buildings to heat and cool the house.

Anchors or Ties

Vertical connectors linking bricks to the interior structural components are consistently used in modern construction to enhance stability and distribute loads effectively. However, in historic construction of the time, these buildings were mostly built without vertical reinforcement. Tie backs or lateral deflection resistance have been added to many facades after original construction, in many cases.

Basement or Crawlspace Foundations

Beneath the facade, typically a triple wythe basement or crawl space foundation supports the entire load path of the building. In many cases basements have been updated with modern finishes in recent decades but historically most were just root cellars with rat sabs added to deter some of the common elements of moisture and rodent entry from below.

Lintels

Positioned above windows and doors, lintels are horizontal structural elements typically made of stone or brick, providing support and preventing differential settlement (collapse and cave-in) above the window or door opening. In historic construction, in Washington, DC, often wooden lintels are hidden behind shallow segmented brick arches, often called “eyebrows”.

cmu intel — The picture above shows an exposed CMU lintel at an old but not historic opening header which our company recently refinished to extend the life of the lintel where it would otherwise rot through from oxidation and rust.

Cast Iron Front Stairs or Masonry Stoop

The cast iron front stairs and masonry stoops are prominent architectural features found in many historic brick buildings in Washington DC. These elements serve as the main entrance to the building, enhancing its visual appeal and contributing to the overall architectural character.

Cast iron front stairs are a distinctive feature commonly found in late 19th-century and early 20th buildings in the historic neighborhoods of Washington, DC. These stairways are designed with intricate and ornate patterns at the stair risers, often with a diamond relief at the treads. The cast iron material is somewhat durable yet lacks the ductility of steel. With proper care and upkeep, the stairs are somewhat durable to withstand the exterior elements over many decades. These stairs often include decorative railings and balusters, adding to the aesthetic charm of the entrance. Cast iron front stairs provide a sense of grandeur and sophistication, making a strong visual statement for the building.

Masonry stoops are another prevalent entrance feature in the historic brick buildings of Washington, DC, particularly in rowhomes. Typically constructed using brick or stone, the stoop is a set of steps leading up to the main entrance of the building. Masonry stoops can vary in size and design, ranging from a few steps to more elaborate structures with midlandings and multiple flights of treads and risers. Like cast iron front stairs, masonry stoops contribute to the building’s architectural character and curb appeal. In addition to providing access to the entrance, the stoop often serves as a gathering space or a place to sit and socialize, particularly more in historic times when families lived together in these buildings across several generations.

Decay and Entropy in Historic Masonry Facades

Decay and entropy in historic masonry’s facade happens for several different reasons or source causes, the list below describes several of those potential sources of introduction of deterioration of masonry facade building systems:

Weathering: Exposure to weather elements such as rain, snow, wind, and temperature variations can lead to physical erosion and chemical reactions that weaken the masonry materials.
Pollution / climate: Air pollution, especially in urban environments, can accelerate the decay process by promoting the formation of harmful compounds on the surface of the masonry. In a coming future article, on our blog, we will discuss the deleterious effects of climate change and how the impacts of climate change will harm buildings at an exponentially increasing rate.
Bioconalization: Moss, algae, lichen, and other biological agents can colonize the masonry and promote deterioration by retaining moisture and causing physical damage.
Poor maintenance: Lack of proper upkeep and maintenance over the years can exacerbate existing issues, leading to more significant damage.
Unskilled contractors: Some of the worst and most harmful damage to masonry buildings can be done by untrained or unskilled contractors using the improper methods of preservation or restoration.
Structural failures: Subsidence or foundation settling can cause cracks and shifts in the masonry, affecting its stability.

Preserving historic masonry facades requires understanding and managing entropy effectively. Conservation efforts typically involve careful assessment, restoration, and regular maintenance to slow down the decay process and ensure the continued longevity and cultural significance of these structures. Skilled contractors, like IDS employ various techniques such as proper historically accurate tuckpointing or repointing, and repairs to protect the masonry to safeguard its integrity and historical value.

Factors Contributing to Decay and Entropy in Historic Brick Facades

We will discuss the following main factors affecting and driving building decay and entropy in masonry facades:

Environmental factors
Material limitations (in terms of durability and longevity)
Human neglect and harm

Some of the most significant threats to historic brick masonry structures in Washington, DC are posed by air pollution, moisture infiltration, global warming, material properties, human activities, and neglect to historic brick masonry facades.

Environmental Factors: Air Pollution and Acid Rain

Air pollution, predominantly caused by industrial emissions and vehicular exhaust, poses a severe threat to brick masonry facades. Airborne pollutants, such as sulfur dioxide (SO2) and nitrogen oxides (NOx), react with atmospheric moisture to form acidic compounds. When acid rain falls on historic brick facades, it initiates a chemical reaction with the calcium carbonate present in the bricks and mortar, leading to erosion and degradation. Over time, this process weakens the masonry’s structural integrity and aesthetic appeal.

Environmental Factors: Moisture Infiltration and Freeze-Thaw Cycles

Moisture infiltration is a common issue in older brick masonry buildings lacking modern waterproofing techniques. When water seeps into the brickwork, it can cause efflorescence and freeze-thaw cycles during colder months. As the water freezes and expands, it exerts pressure on the bricks and mortar, leading to cracking and spalling. With repeated freeze-thaw cycles, the masonry gradually deteriorates, risking irreversible damage.

Environmental Factors: Global Warming and Its Impact on Masonry Conditions

Global warming intensifies the impact of environmental factors on historic brick masonry facades. Rising temperatures increase the rate of chemical reactions, accelerating the decay process. Additionally, increased frequency and intensity of extreme weather events, such as heavy rainfall and storms, worsen moisture infiltration issues. These factors collectively contribute to a faster deterioration of masonry structures, demanding more frequent maintenance and conservation efforts.

Material Limitations: Susceptibility of Historic Low Temperature Fired Bricks and Soft Lime Mortar:

Many historic brick masonry facades were constructed using low-temperature fired bricks and soft lime mortar. These materials are more porous and less durable compared to modern counterparts. As a result, they are highly susceptible to environmental factors like water infiltration, freeze-thaw cycles, and acid rain. The gradual breakdown of these materials over time poses significant challenges for preservation efforts.

Material Limitations: Variation in Craftsmanship and Lack of Oversight

The quality of craftsmanship during the construction and restoration of historic masonry varies considerably between contractors. Some restoration work may not adhere to proper pointing techniques, leading to compromised mortar joints and increased vulnerability to moisture infiltration. Furthermore, the absence of effective industry-specific oversight from the authority having jurisdiction in Washington, DC, may result in subpar restoration practices, further endangering the integrity of brick masonry facades.

Material Limitations: Aging and Wear-and-Tear Effects

As with any historical structure, aging and regular wear-and-tear impact the condition of brick masonry facades. Continuous exposure to natural elements, pollution, and human activities contributes to the gradual degradation of the facade’s appearance and structural stability. Regular maintenance and timely repairs are essential to counteract the effects of aging and prolong the longevity of these historic structures.

Human Neglect and Harm: Lack of Maintenance and Repair

One of the primary threats to the preservation of historic brick masonry facades is the lack of proper maintenance and timely repairs. Neglecting minor issues can lead to more extensive damage over time, necessitating costlier restoration efforts. A consistent maintenance plan, including routine inspections and immediate repair of defects, is crucial to mitigate potential deterioration.

water entry from exterior facade — The picture above shows an example of where water entry from the exterior facade of a building has infiltrated into the interior ceiling of a bathroom causing damage, both to drywall and other interstitial hidden materials.

Human Neglect and Harm: Inappropriate Restoration Techniques

Inappropriate restoration techniques, such as the use of incompatible modern materials or aggressive cleaning methods, can harm historic masonry facades. Improper interventions may alter the facade’s original appearance and compromise its historical integrity. Adherence to preservation guidelines and employing experienced conservation professionals is vital to safeguard these irreplaceable architectural gems.

Human Neglect and Harm: Adjacent Urban Development and Construction

The presence of ongoing urban development and construction activities near historic brick masonry facades poses a risk of damage due to vibrations, increased air pollution, and potential water runoff issues. Proper planning and coordination between preservation authorities and construction agencies are necessary to protect these vulnerable structures during adjacent development.

Preserving historic brick masonry facades is a multifaceted endeavor that requires addressing a range of challenges posed by environmental factors, material properties, and human activities. To ensure the longevity and cultural significance of these buildings, a proactive approach that includes regular maintenance, compatible restoration techniques, and collaboration between preservation authorities and stakeholders is essential. By protecting these historic structures, we can value our architectural heritage and preserve it for future generations.

Preservation and Conservation Strategies

Preserving and conserving historic brick masonry needs to start with analyzing and understanding the current condition, planning and executing the preservation and or restoration of the facade.

Conditions Survey

Perform a comprehensive conditions survey of the brick masonry facade to assess its current state. This survey should identify areas of deterioration, water infiltration, cracking, efflorescence, and other signs of damage. Understanding the facade’s condition is crucial for developing an effective preservation plan, you can hire a company like IDS to help.

Water Diversion Management

Proper water management is crucial for the preservation of historic brick masonry. Water is a significant contributor to deterioration, as it can cause efflorescence, freeze-thaw damage, and entropy and erosion of the mortar. Implement strategies to divert water away from the brick facade, including the following:

Gutters and Downspouts: Install or repair gutters and downspouts to channel rainwater away from the building’s facade and foundation.
Grading: Ensure the grading around the building slopes away from the structure to prevent water from pooling near the building foundation.
Splash Blocks or downspout extensions: Use splash blocks or extend downspouts to direct water away from the building where original underground rain leader connections are defunct or not available.

coverings on masonry — The picture above shows the front facade of a building in DC. The masonry was covered with a siding which isn’t very common or necessarily effective. We see some examples of other materials used as coverings over masonry in DC such as formstone, from time to time. In this case the downspout was extended away from the building because without a working underground drain, the water matriculated down into the basement in close proximity to the electrical panel. The pathway of the water was a trail of deterioration and destruction.

Tuckpointing and Repointing

Over time, the mortar joints between the bricks can deteriorate due to weathering and aging. Tuckpointing and repointing are techniques used to replace the deteriorated mortar and restore the structural integrity of the brick masonry. The process involves carefully removing the old mortar and replacing it with new mortar that matches the historic appearance. It is crucial to use compatible materials and techniques to avoid damaging the historic fabric of the facade during repointing.

Maintenance and Regular Inspections

Regular maintenance and periodic inspections are essential for early detection of issues and prompt intervention. Implement a maintenance plan that includes regular inspections, cleaning, and minor repairs to address potential problems before they escalate.

rear facade of building — The picture above shows the rear facade of a building in DC, in a rear ell area of the building. A stair-step crack has formed. The diptych repeat of the image allows the comparison between a markup highlighting the area of structural failure. The building conditions should be surveyed regularly, at least annually to identify areas of damage to limit and deter exponentially expanding deterioration.

Professional Preservation Expertise

Engage with professionals experienced in historic preservation and conservation of masonry facades, like IDS. This ensures that all restoration and repair work is carried out in accordance with best practices and adheres to conservation guidelines. Preserving historic brick masonry facades is a delicate process that requires a thoughtful approach, expertise, and a commitment to maintaining the building’s historical value for future generations.

Collective efforts the preserve historic facades are missing

The lack of collective efforts in safeguarding our architectural heritage through proper preservation and conservation measures is noteworthy. A authority having jurisdiction is also known as an AHJ period in areas of America such as Washington DC, for example, there are many AH j’s. One of the main AH j’s is DCRA. DCRA, for example has the authority to stop construction if the construction is being done incroperly. Osha, on Also has the ability to stop construction if it’s being done without proper safety precautions and we’re following the relevant safety rules mandated by osha related to construction.

The historic review board also can impose requirements related to construction within certain neighborhoods of Washington DC. All of these different AH j’s, are examples of the various sets of requirements. Often theVarious types of requirements and/or rules are not coordinated by an overarching entity. Instead, it’s often the responsibility of the property owner to verify that all varied requirements are being simultaneously fulfilled.

The governing bodies end where AH j’s in Washington DC seem to recognize the historical and cultural and even economic value of maintaining and preserving historic properties. Largely though there is very little Enforcement or even encouragement for contractors to follow best practices. The building code is one of the main standards governing the minimum requirements for quality and construction. The building code though includes very few provisions related to upkeep, maintenance, reconstruction, and or preservation and restoration of historic masonry, for example.

Historic masonry upkeep and preservation

To 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.

Entropy In Historic Masonry Facades And Structures