Metal Panels Support Sustainability in Seattle Office and Shopping Center

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At 35 Stone in Seattle, Wash., metal wall and roofing panels contribute to the sustainable function and the industrial-inspired appearance of a high-performance office building near the city’s Lake Union Waterfront.

Constructed as a neighborhood-focused workplace and retail center, the building is a showcase for Seattle’s Living Building Pilot Program. It combines inspiration from Seattle’s origins with its mass timber framework and modern styles, including metal wall and roofing panels.

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According to a description on the Weber Thompson website, the five-story office building/retail space is a “showcase for environmental stewardship.” It was designed to meet market demand for workplaces that support health and wellness. The project participated in the city’s Living Building Pilot Program, which gives additional area and height to buildings that meet rigorous energy and water reductions, along with three-petal certification from the International Living Future Institute.

“Water reduction requirements meant that we needed the roof to capture as much of the rainwater as possible and direct it to a [1,020,000-L] 270,000-gallon onsite cistern,” Kristen Scott, AIA, LEED AP, senior principal at Weber Thompson in Seattle, says. “The standing seam metal roof minimizes water loss due to evaporation while supporting the water capture for reuse onsite for toilet flushing, exterior hose bibs, and irrigation. An integral gutter system collects rainwater, allowing the roof to turn down and become the exterior siding material on the east and west facades. The contrast of the standing seam metal paneling and the curtainwall glazing is eye-catching and a big part of the visual identity of the design.”

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The structure includes two wall panel profiles and 1,672.3 m² (18,000 sf) of a single standing seam roofing profile. The 22-gauge, 304.8 mm (12 in.) TBC-Superseam roof panel in custom Smokey Blue captures rainwater. The wall panels were 22-gauge, 304.8 mm (12 in.) TBC-Ultra, measuring 1,319.2 m² (14,200 sf), produced in custom Smokey Blue and 0.81 mm (0.032 in.) aluminum 7/8 corrugated panels, measuring 1,235.6 m² (13,300 sf), in custom Wescott Navy. The building also includes 148.6 m² (1,600 sf) of custom perforated panels.

“The standing seam wall panels were particularly challenging since they have staggered transverse seams,” says Kristi Gouy, senior project manager at Northshore. “The panels are [304.8 mm] 12 in. wide, so alignment across the entire facade was crucial to the final look.”

The unique design and extra diligence during installation ensured effective rainwater harvesting. “[The] standing seam metal roofing product allowed us to create the ‘hard shell’ form with the continuous use of the material for the sloping roof transforming to exterior siding while concealing an integral gutter,” says Scott. “This expression forms a key part of the overall design concept for the building.”

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The perforated corrugated steel mesh screen on the exterior stairs provides some weather protection while still allowing for good daylighting and visual connection with the outdoors. “At night, the interior lights shining through the perforations create a lantern effect,” says Scott.

In addition to the cistern that saves more than 50 percent of water use compared to a typical Seattle commercial property, construction of 35 Stone uses 25 percent less energy than a typical building with finely tuned glazing placement to maximize views while balancing heat gain. Four rooftop bee hives produce more than 45.4 kg (100 lb) of honey annually. Educational signage around the site connects to both the pre-development and post-industrial history of the site and highlights building performance features of the community.