APT Seattle Conference Symposium 2023: Aging Composite Materials and Assemblies

Aging modern heritage buildings and structures face complex repair and reinvestment challenges. Manufactured composite materials and multi-material assemblies often cannot be cost-effectively repaired or replaced in kind. Many proprietary products used to construct midcentury modern buildings are no longer manufactured. Others contain components, such as asbestos and polychlorinated biphenyls (PCBs) or chlorofluorocarbons (CFCs) that are toxic or hazardous to the environment. Little research or guidance is available to assist practitioners in identifying appropriate substitutes and approaches that balance heritage stewardship, safety, environmental, lifecycle performance and resilience goals for sound long-term treatment.

In the face of these constraints, APT TC-MH invites members, scholars, and other practitioners to contribute their perspectives, experiences, and wisdom in a working session to articulate model approaches and develop guidance for the sound, responsible and cost-effective treatment of composite materials and assemblies.


  • Post World War II Facade Technology Overview: Innovations & Lifecycle Challenges. David Fixler, FAIA/FAPT, Principal, Fixler Architects & APT Technical Committee on Modern Heritage Co-Founder
  • Identifying, Removing, Mitigating Hazardous Materials. Bill Parks, Senior Project Manager, F.D. Thomas.
  • NPS Substitute Materials brief update. John Sandor, Senior Historian, National Park Service, Technical Preservation Services and Editor,
  • Repair, Replacement, and Encapsulation of Asbestos Cement Exterior Panels at the Eames House. César Bargues Ballester, Associate Project Specialist, Getty Institute. Chandler McCoy, Senior Project Specialist, Getty Institute
  • Green Skins for Old Bones: Design for Disassembly and Sustainable Facade Retrofit. Mic Patterson, Ambassador of Innovation & Collaboration, co-founder, Facade Tectonics Institute.
  • Reevaluating Past Projects, Rethinking Reinvestment: Decision-Assisting Tools to Achieve Preservation & Performance Goals. Beth L. Savage, Federal Preservation Officer and Director, Center for Historic Buildings, US General Services Administration.
  • Future-Proofing, Charters, and Standards: Integrating Principles into Practice. Brian Rich, Principal, Richhaven Architecture & Preservation.

Learning Objectives

  1. Identify analysis and decision-making tools for weighing composite material repair and replacement alternatives
  2. Describe options for avoiding, minimizing or mitigating hazardous materials in composite material assemblies and products.
  3. Apply preservation treatment standards to character-defining, limited life and toxin-containing materials and assemblies
  4. Conceptualize alternatives for balancing environmental, conservation, sustainable performance, and sound reinvestment goals in addressing the deficiencies of poorly performing composite materials and assemblies.
  5. Prescribe encapsulation and intervention strategies for mitigating hazardous component risks while minimizing loss of character-defining materials.
  6. Specify design and construction requirements for ensuring access to intervention areas for future maintenance and repair.

Format: Slide lectures & interactive discussion/working sessions


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