Smithsonian Institution, National Air and Space Museum: Mall Building Revitalization

Title: Smithsonian Institution, National Air and Space Museum: Mall Building Revitalization

Award Category: Building Enclosure

Project Address/Location

National Air and Space Museum
600 Independence Avenue, SW
Washington, DC 20560
United States

Submitted By: Sam Zalok

Company Info

Simpson Gumpertz & Heger Inc.

1625 I Street
Suite 900
Washington, DC 20006
United States

2403771030

[email protected]

Project Description and Background: With nearly 700,000 sq ft of exhibit space and millions of annual visitors, the Smithsonian Institution’s (SI) National Air and Space Museum (NASM) has long been one of its most iconic landmarks. SGH has supported the Smithsonian on this building since our first enclosure assessment in 1980, and we were engaged as enclosure consultants for the museum’s comprehensive modernization, expected to open in July 2026. The high-profile nature of the revitalization—and the responsibility of preserving priceless artifacts—demanded rigorous scrutiny of enclosure assumptions, performance analyses, and system selections. A central challenge was the reintroduction of mechanical humidification, critical for artifact preservation but highly complex for the enclosure. Elevated humidity levels increased the risk of condensation forming on interior surfaces, with the potential to damage exhibits representing milestones of technological history. Historically, preventing condensation in this type of environment had relied on ad hoc design solutions. For NASM, however, SGH used advanced computational fluid dynamics simulations to model airflow, temperature, and condensation potential in the atria. The results accounted for multiple interacting factors, including diffuser discharge conditions, facade heat loss, exterior climate variations, and localized obstructions. These analyses allowed the design team to test multiple scenarios, evaluate risks, and select solutions with confidence. SGH also evaluated proposed enclosure systems and rehabilitation strategies, focusing on durability, energy efficiency, and compatibility with the museum’s architectural vision. A key outcome was proving that high-performance enclosures and modern analysis methods could achieve strict conservation goals without sacrificing daylight-filled atria or the original architectural intent. This project demonstrates that not all modern museums must be opaque, controlled boxes. Through innovative use of simulation tools and careful enclosure design, the revitalized NASM will remain both a transparent cultural icon and a state-of-the-art environment for artifact preservation.

Scope: The NASM revitalization began with a fundamental question: how could the Smithsonian preserve the character of a beloved landmark while updating its performance for modern conservation and sustainability standards? To answer this, the project required a comprehensive understanding of the existing building enclosure systems and the risks of proposed interventions. SGH was engaged to investigate, test, and analyze the enclosure and to guide the design team through decisions that would shape both the preservation strategy and the museum’s long-term resilience. Our work began with an extensive investigation program to understand the enclosure’s existing condition. Using infrared imaging, water testing, roof test cuts, and probe openings at both the stone and glazing systems, we identified deterioration and failure mechanisms to address. These diagnostic findings informed the feasibility study, where we evaluated potential cladding and roofing materials for durability, sustainability, and compatibility with photovoltaic panels. We also assessed the feasibility of reintroducing mechanical humidification into the museum, including condensation risks associated with higher humidity levels. Through an open and collaborative effort, we worked with the architectural team and Smithsonian to evaluate options for refurbishing the existing enclosure systems in place versus demolishing the systems and introducing new systems. Total enclosure replacement proved to be the most viable option, and the most sustainable due to the improved modern performance and longevity. During the design phase, SGH worked closely with the architect, Quinn Evans, to develop robust details and establish basis-of-design performance metrics for thermal, solar, and condensation resistance. We analyzed curtain wall and skylight systems using computational fluid dynamics and iterative two-dimensional heat transfer models to predict condensation behavior under different conditions. This methodology provided confidence that the revitalized museum could achieve strict conservation goals while maintaining the openness and daylight that define its architecture. SGH’s role extended into design assist, where we collaborated with the general contractor, Clark/Smoot/Consigli, and enclosure fabricators to refine solutions and develop novel assemblies. We worked with the stone-clad curtain wall provider, Rugo, to test table-top mockups; with the vestibule provider, Roschmann, to integrate PTFE canopy roofs and structural glass into the parabolic geometry; and with international fabricators to review quality-control procedures. We also reviewed integrated laboratory performance mockups to validate system durability and performance before installation. In the construction phase, SGH continued as an active partner, participating in preconstruction and commissioning meetings, reviewing submittals and shop drawings, observing third-party field testing, and visiting the site to verify installation quality. One notable outcome was the careful study of the museum’s original Tennessee Pink marble cladding. Laboratory testing revealed the stone could not remain in place, but the project team, guided by SGH’s input, explored reuse and recycling strategies. While large-scale reuse proved unfeasible, the team successfully retained portions of the stone for interior walls and finishes, preserving a tangible link to the original building. Through this full scope of investigation, analysis, design collaboration, and construction support, SGH ensured that the NASM revitalization achieved both performance excellence and cultural stewardship.

Solution: Designing the right solutions for NASM meant balancing state-of-the-art technology with respect for the original architecture. Every decision had to serve dual purposes: protect priceless artifacts while maintaining the museum’s iconic identity. The project team, supported by SGH’s analysis and design input, developed a series of innovative strategies that integrated advanced materials, computational modeling, and testing to achieve this balance. Glazing Systems The blast resistance proved to be the critical metric for the glazing systems. The basis-of-design system consisted of a traditional aluminum stick-built curtain wall and skylight systems with steel reinforcing where needed to resist the design loads. Through the bidding process, a ladder-framed steel curtain wall system proved to be the most efficient use of cross-section. SGH equipped the stakeholders with the technical information necessary to evaluate the potential change, including impacts on appearance, performance, construction quality control, etc. Due to the monumental size of the glass-enclosed atria, the skylight’s thermal and solar control performance greatly influenced the mechanical system’s design. The project team, with SGH’s guidance, iterated enclosure and mechanical analysis. Performance values for proposed glazing were calculated, fed into energy models, and tested against conservation criteria. Life-cycle cost analyses and condensation analysis justified the use of triple-glazing at the skylights. Daylighting simulations reviewed ceramic frit patterns and visible light transmittance to ensure energy efficiency without compromising artifact preservation. Stone-Clad Curtain Walls Our site investigation determined the original marble panels had deteriorated beyond reuse, but their cultural presence could not be lost. SGH helped develop a concept for supporting new granite panels on a modified aluminum curtain wall frame. The aluminum frame allowed for a compact wall that could be quickly hung from the structure. The aluminum frame also allowed for thermal breaks to improve U-factor and condensation resistance while creating supports for heavy stone cladding. Insulated metal panels between the mullions created continuous air, water, thermal, vapor, and blast-resistant control layers. This approach minimized structural strengthening and offered a modern, robust reinterpretation of the original lightweight system. Vestibule The new vestibule addition exemplifies innovation and is the crowning feature of the revitalized facade. Its structural glass curtain wall, supported by laminated glass mullions, creates a transparent entry experience while providing a new space for modern security screening. Above, a PTFE tensile membrane roof follows a 3D parabolic curve inspired by da Vinci’s ornithopter, achieving both symbolic resonance and technical excellence. Every piece of the vestibule enclosure is visible from the interior and exterior, so partnership with the facade contractor was key to craft novel solutions for every transition. Testing and Verification Performance was validated through laboratory mockups, shop quality-control reviews at fabrication facilities, and third-party field testing. These commissioning steps ensured that proposed solutions not only met but exceeded expectations, aligning with the museum’s preservation mission and sustainability goals. Together, these solutions demonstrate how state-of-the-art analysis, innovative materials, and collaborative detailing can reimagine a historic icon for the future while honoring its original vision.

Value: What distinguished the NASM revitalization was not only the technical complexity of the enclosure systems, but also the high stakes of failure: condensation, air leakage, or premature deterioration could put irreplaceable collections and the Smithsonian’s reputation at risk. The NASM project aimed to serve as a benchmark for American museum modernizations. The involvement of a dedicated enclosure consultant brought assurance at every stage. SGH’s contributions added value by aligning performance, constructability, and conservation goals, ensuring the museum’s transformation was both technically sound and true to its cultural significance. One of the most significant contributions was resolving the tension between conservation requirements and architectural intent. The reintroduction of mechanical humidification was critical for artifact preservation but carried a high risk of condensation within the atria. SGH’s advanced computational simulations, paired with iterative energy and enclosure modeling, allowed the design team to understand risks, test strategies, and ultimately implement solutions that preserved the daylight-filled spaces while protecting irreplaceable artifacts. The consultant’s involvement also added value by bridging design vision and fabrication realities. SGH collaborated directly with enclosure system providers—reviewing tabletop mockups, laboratory performance tests, and international shop quality control procedures—to refine assemblies before they reached the field. This hands-on engagement helped prevent costly redesigns, maintained schedule reliability, and gave the Smithsonian confidence that proposed solutions would perform as intended. During construction, SGH’s ongoing participation in submittal reviews, commissioning meetings, and field observations provided an additional layer of quality assurance. This support ensured that the innovative systems—ranging from stone-clad curtain walls to structural glass vestibules and PTFE canopies—were not only well designed but also well executed. The involvement of IIBEC members in this project was vital. Their expertise in building enclosure science enabled the team to navigate complex technical challenges, balance performance with preservation, and achieve measurable outcomes in energy efficiency, artifact protection, and sustainability. SGH’s contributions exemplify how specialized enclosure consultants add lasting value to high-profile, high-performance projects. SGH relied on a deep bench of IIBEC-credentialed consultants and IIBEC members to develop informed, fair, and appropriate design recommendations and quality control work product. IIBEC team members include Gregory Doelp, Benjamin Hiltz, and Caroline Byrne. SGH’s long partnership with IIBEC and alignment with IIBEC’s goals helped to provide the project team with an industrywide vision for durable enclosure performance.

Additional Info: Relevant Articles • APT: https://www.jstor.org/stable/26753886 • ENR: https://www.enr.com/articles/58515-a-monumental-museum-makeover • Architect’s Newspaper: https://www.archpaper.com/2022/10/smithsonian-national-air-space-museum-reopen-eight-renovated-galleries-museum-overhaul/ • Washington Post: https://www.washingtonpost.com/dc-md-va/2025/07/30/national-air-space-museum-reopens-smithsonian-exhibits/

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