Unreinforced Masonry Buildings - What & Why

What’s Happening Now?

In December 2021, the City Council passed Resolution 32033 which establishes the framework for a phased-in mandatory retrofit ordinance for Seattle’s 1,100 unreinforced masonry buildings (URMs). These buildings, typically built before 1945, are made of brick or clay tile without structural reinforcement and are prone to collapse in an earthquake.

The primary goal of the future URM Retrofit Ordinance is to improve life safety by reducing the risk of injury from collapse of URM buildings in the event of an earthquake. Additional goals include:

• Preserving Seattle’s historically and culturally significant landmarks and structures that contribute to neighborhood character
• Improving the City’s resilience to earthquakes
• Minimizing the impact of the retrofit program on vulnerable populations to the extent financially feasible

In October 2023, City Council passed Resolution 32111 which directs SDCI to use the Draft URM Retrofit Technical Standard to inform voluntary URM retrofit legislation. This legislation will be implemented as a code change to the Seattle Existing Building Code (SEBC), with a goal of adoption in late 2024. The code will define minimum seismic safety requirements for a retrofitted URM building and establish the alternate method for URM retrofit. The alternate method is a less restrictive method than the current code-based method, that minimizes cost and collapse hazard. While currently voluntary, the City plans to pursue mandatory URM retrofit legislation in the future, once we have identified supportive resources and funding mechanisms. Please note: a voluntary seismic improvement on its own does not trigger a substantial alteration designation.

Learn more about the history, analysis, and studies that supported development of this resolution on the Background and Timeline pages.

To implement Resolution 32033, SDCI has begun work through two separate tracks: policy development, focused on communication and financial resources, and technical standard development, focused on changes to the Seattle Existing Building Code to include the updated Technical Standard for the retrofit of URM buildings.

Policy Development:

Work is underway, in coordination with other departments and external partners, to develop a communication strategy for the community (including building owners as well as those living in current URM buildings) and identify resources to reduce the costs and impacts associated with seismic retrofits. A series of working groups have been developed which are focused on communication and financial resources.

The URM Policy Development Working Groups include:

1. A Technical Standard Briefing Working Group with the intent of providing a forum for questions and answers on the retrofit technical standard.
2. A Communications Working Group with the intent of developing materials to support community engagement and acceptance.
   1. A sub-group has been created to focus on developing neighborhood-focused retrofit case studies.
3. A Funding Working Group with the intent of exploring ways to mitigate the cost of URM retrofits. Two sub-groups have been created:
   1. A Retrofit Credit/Transfer of Development Rights Sub-Group with the intent of developing a new type of transfer of development rights program to finance the retrofit of URMs.
   2. A Grant and Finance Sub-Group with the intent of identifying financing mechanisms to support URM retrofits.
4. An Owner and Tenant Needs Working Group with the intent of addressing physical and economic displacement associated with URM retrofits.

Technical Standard:

A team of structural engineers have updated the 2012 Technical Standard to reflect changes in building codes and a better understanding of Seattle’s earthquake hazard. The updated draft URM Retrofit Technical Standard and supporting Director’s Rule are the first step in establishing a baseline retrofit standard for the voluntary retrofit of URM buildings. The Director’s Rule and Technical Standard will be used to inform the phasing in of a mandate for the seismic retrofits of URMs as requested in Resolution 32033.

• Director’s Rule 6-2023, A Method for the Seismic Improvement of Unreinforced Masonry (URM) Buildings. The intent of this rule is to provide a voluntary methodology for seismic improvements to URMs which addresses testing and quality of existing masonry constructions and mitigates collapse hazards in an earthquake.This rule will formally provide a pathway for the alternate method for retrofit, reducing costs to building owners compared to a code-based retrofit while increasing the life safety of the building.
• Components of the Draft URM Retrofit Technical Standard have been adopted through the above Director’s Rule. It is SDCI's goal to adopt the draft Technical Standard into the Seattle Existing Building Code (SEBC) to establish minimum compliance standards for the retrofit of URMs, as requested in Resolution 32033.
  • We held two virtual public meetings providing opportunities for questions and answers on the draft URM Retrofit Technical Standard on June 8, 2023, and June 12, 2023. Be sure to check out slides and recording from these presentations.

Learn more about this work, on the Project Documents page.

To learn how you can get involved in the development of this ordinance and implementation resources, go to the Get Involved page.

Project Benefits

In the next 50 years, Seattle has an 86 percent chance of experiencing a magnitude 6.8 earthquake and a 33 percent chance of experiencing a magnitude 8 earthquake. A mandatory unreinforced masonry retrofit ordinance will improve the life safety of over 1,100 collapse-hazard buildings. The required earthquake retrofit will reduce the probability of injuries, fatalities, and long-term displacement to the over 22,000 people who live or work in URM buildings. Earthquake retrofits of URMs will reduce business closures post-earthquake and increase building reoccupancy timelines, thus allowing for a quicker recovery and reduction in economic impacts.

Additional benefits of the mandatory URM retrofit ordinance include increasing the earthquake resilience of many historic, landmark, and culturally significant buildings throughout the city.

The End Result

An ordinance requiring the mandatory earthquake retrofit of URMs will be adopted. Current proposed URM retrofit legislation is voluntary with plans to require mandatory retrofit once supportive resources become available. Voluntary URM retrofit legislation is intended to be adopted late 2024. Building owners will have advance notice of the mandatory URM retrofit ordinance, retrofit requirements, compliance timelines, and available supportive resources.

The future mandatory ordinance will include a baseline retrofit standard for URM buildings, requiring stabilization of the building to reduce probability of collapse in an earthquake. The baseline retrofit standard will not bring URMs up to current code; building owners are encouraged to consult a structural engineer to retrofit to higher performance standards and to consider additional resiliency factors such as energy efficiency and emission reduction upgrades during the retrofit process.