Where Are Washington’s Unreinforced Masonry Buildings: Exploring the Vulnerability of Seattle’s Architecture

Washington state is home to a remarkable variety of architectural gems, but hidden amongst it’s impressive skyline and elegant facades lies a hidden danger – unreinforced masonry buildings. These structures, often unnoticed by the untrained eye, pose a considerable risk to public safety in the event of an earthquake. Washington's vibrant urban landscapes, from the bustling streets of Seattle to the rich historical tapestry of it’s smaller towns, conceal a number of these vulnerable buildings. Whether tucked away in quiet neighborhoods or standing prominently in the heart of the city, these unreinforced masonry buildings silently wait for their chance to reveal their true nature. From charming storefronts to iconic landmarks, these structures stand as relics of a bygone era, showcasing the stone and brick craftsmanship of yesteryears. However, their intrinsic vulnerability to seismic activity necessitates urgent attention and strict retrofitting measures. As seismic activity continues to threaten the region, it’s imperative to identify and address the prevalence of Washington's unreinforced masonry buildings to safeguard the lives and well-being of those who inhabit and visit the Evergreen State.

How Do You Tell if a Building Is Unreinforced Masonry?

Determining whether a building incorporates unreinforced masonry can be crucial in assessing it’s structural integrity and vulnerability to seismic activity. Although a thorough examination by a professional is recommended, there are a few key signs that can indicate the presence of unreinforced masonry.

One telltale sign is the visible presence of rafter tie plates. These plates, usually made of metal, are used to help secure the roof framing to the walls in buildings with unreinforced masonry. If you can spot these plates from the exterior, it may suggest the absence of reinforcement within the masonry.

Another indicator is the deep recess of windows. In unreinforced masonry buildings, windows are often set back further from the exterior surface. This design feature acts as a precautionary measure, providing additional protection to the window frames during potential seismic events.

Observing the presence of a concrete bond beam cap is also significant. These caps are typically seen on top of the external walls, either over windows or between floors. Bond beams add strength and stability to the masonry walls and can be a prominent sign of reinforcement.

First, the bricks may not be uniformly laid, indicating a lack of structural reinforcement. Additionally, the mortar between the bricks may be white and easily peel away with minimal effort. This suggests that the mortar may not be strong enough to hold the bricks securely, potentially indicating a lack of adequate reinforcement.

They possess the expertise and knowledge to conduct a thorough inspection, ensuring the safety and stability of the building.

However, not all URMs are created equal. One example of an unreinforced masonry building is the iconic row houses found in cities like San Francisco. These buildings, with their distinct architectural charm, were constructed in large numbers during the late 19th and early 20th centuries. While visually appealing, they often lack structural support, making them susceptible to seismic activity. It’s crucial to identify and address the vulnerabilities of such buildings to ensure the safety of their occupants and preserve historical heritage.

What Is an Example of an Unreinforced Masonry Building?

One example of an unreinforced masonry building is the iconic Brownstone townhouses found in areas like Brooklyn and Harlem in New York City. These buildings were primarily constructed in the late 19th and early 20th centuries and are characterized by their distinct brownstone facades. While aesthetically charming, these buildings lack the necessary reinforcement to withstand seismic activity effectively.

Another example of a URM is the traditional adobe houses found in parts of the American Southwest, such as New Mexico and Arizona. These houses were constructed using clay, straw, and water, forming thick walls without any additional reinforcement. While adobe buildings have cultural significance in these regions, they’re vulnerable to earthquakes due to their fragile nature.

In Europe, particularly in countries like Italy and Greece, many historic structures, including churches, castles, and palaces, are examples of unreinforced masonry buildings. These magnificent structures were built centuries ago without the knowledge of modern seismic standards, making them susceptible to earthquake damage.

Furthermore, in countries like Nepal and India, there are numerous unreinforced masonry buildings that have been constructed throughout history. Rural areas in these countries often have homes, temples, and public buildings made from locally available materials like stone or brick, which lack reinforcement against seismic forces.

These buildings, lacking the reinforcement necessary to withstand earthquakes, are at higher risk of damage or collapse during seismic events. As society becomes more aware of the dangers posed by URMs, efforts are being made to retrofit or replace these structures with more seismically resistant alternatives.

Unreinforced masonry buildings, due to their structural vulnerabilities, are highly susceptible to severe damage or even collapse during an earthquake, regardless of it’s intensity. The aftermath of such an event often necessitates significant repairs, leading to lengthy closures and significant financial burdens.

Can Unreinforced Masonry Building Be Severely Damaged by a Earthquake?

Unreinforced masonry buildings, which are structures made of bricks or stone held together by mortar without any reinforcing elements like steel bars, are particularly vulnerable to earthquake damage. The lack of reinforcement makes these buildings much less resistant to the intense shaking caused by seismic activity. Even a minor earthquake can induce significant stress on the masonry walls and other structural components, leading to severe damage or even collapse.

Moreover, these buildings often have vulnerable connections between the various components, such as the roof, floors, and walls. The shaking caused by an earthquake can cause these connections to loosen or detach completely, further compromising the structural integrity. In some cases, the roof may separate from the walls, leading to a complete structural failure of the building.

Addressing the damage caused by an earthquake in an unreinforced masonry building can be an arduous and costly process. Extensive repairs or even complete reconstruction may be necessary to restore the buildings integrity and ensure it’s safety. Given the potential risks associated with these structures, it’s crucial to prioritize seismic retrofitting or consider alternative building methods that provide better resistance to earthquake forces.


In conclusion, the issue of Washington's unreinforced masonry buildings remains a substantial concern for public safety. While efforts have been made to identify and mitigate the risks associated with these structures, their widespread presence and potential for collapse in the event of an earthquake can’t be ignored. The need for comprehensive assessments, targeted retrofitting, and potential removal of these buildings should be a priority for both government agencies and property owners. By addressing this issue head-on, Washington can significantly reduce the potential loss of life and property damage, ensuring a safer and more resilient built environment for it’s residents.

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