Sprouts Farmers Market, renowned for its fresh produce and healthy products, is a recognizable presence nationwide. The store interiors are known for their open and airy design, providing excellent visibility from various angles and a warm, inviting feel. For years, the company’s design and construction teams had relied on steel to achieve this particular look and layout. However, recent logistical issues with steel supply prompted the project team to explore engineered wood for a new location in Norwalk, California. The shift to engineered wood demonstrated its ability to meet span and load requirements while preserving the project’s essential design characteristics.
Initially, the store was designed like other Sprouts Markets, featuring an all-steel roof system, including a metal deck, steel girders, and a steel bar-joist system. However, extended lead times for steel necessitated a material change. Engineer Mo Kateeb, the principal of A.V. Schwan & Associates, turned to wood component manufacturer G2 National to explore wood alternatives that could retain the store’s signature aesthetics, volume, and performance, especially considering the high seismic area.
Although the shift to a light-frame engineered wood roof system was initially necessitated by material challenges, the benefits discovered during the process have led to the adoption of the wood design for future Sprouts locations. Kateeb, who has worked on Sprouts projects for nearly a decade, found that the engineered wood system effectively withstood roof loads and spans, sparking his interest in using it for grocery stores. The new engineered wood roof system included glulam girders from APA member DR Johnson Wood Innovations with a span of 36 feet, an oriented strand board (OSB) deck, and G2’s G2T 8-foot o.c. panelized wood-plated truss system with laminated veneer lumber (LVL) top and bottom chords. The use of higher-strength LVL from APA member Roseburg Forest Products enhanced the roof supports’ bending capacity and allowable span, making it competitive with the steel bar-joist system. The G2T system utilized flush hangers, similar to the original steel system.
With this light-frame system, minimal modifications were necessary compared to the original steel design, except for a slightly lower clear height due to the deeper truss depth. However, the wider 8-foot o.c. spacing for the wood trusses compensated for this reduction, resulting in minimal impact on overall volume despite the deeper framing members. Kateeb worked on anchoring the walls with straps, hold-downs, and diaphragm anchors to support the reinforced masonry walls out-of-plane to accommodate seismic loads. The transition from steel to engineered wood was relatively smooth, facilitated by collaboration between the engineer, architect, and the detailing provided by G2 National. The use of the engineered wood system accelerated the installation process, eliminating the need for certified welders on-site and additional inspectors. A local contractor experienced in panelized roofs was recommended by G2, further streamlining the coordination and construction process. Additionally, the exposed wood added warmth to enhance the store’s natural ambiance.
In addition to staying on schedule, the switch from a steel roof system to a panelized wood system significantly reduced the grocery store’s carbon footprint. A life-cycle assessment (LCA) indicated that the switch resulted in a 69% reduction in the building’s overall embodied carbon. The use of OSB panels instead of a metal deck further reduced CO2 emissions by 49,707 kg, accounting for 51% of the total reduction in the roof system’s CO2 emissions. This transition has prompted some eco-conscious companies to consider switching from tilt-up concrete walls to cross-laminated timber (CLT) to achieve a smaller carbon footprint while maintaining the same interior volume. This innovative approach demonstrates the potential of engineered wood in addressing supply chain challenges, reducing environmental impact, and achieving design goals.