photo by Joshua Jay Elliott, courtesy of Works Progress Architecture, LLP

The City of Portland, Ore.’s 10-story, mixed-use, transit-oriented development known as Slate earned LEED Gold certification through the U.S. Green Building Council. Formerly called Block 75, the building features window, entrance and unitized curtainwall systems by Wausau Window and Wall Systems.

photo by Joshua Jay Elliott, courtesy of Works Progress Architecture, LLP

Designed by Works Progress Architecture for co-developers Urban Development Partners and Beam Development, the property conveys a “push and pull” theme exemplifying the location’s vibrancy. The glass, metal and concrete façade consists of articulated, modulated, rectangular shapes, including some that are setback and some that project over the sidewalks below.

“It creates the illusion of a shifting stack,” says Works Progress Architecture’s Ian Roll. “On the North and South sides, the curtainwall has a flat, clean, crisp look that transitions to a sculpted, figural texture on the East and West elevations. The curtainwall is crucial in registering the intentional lines and visual elements.”

Roll notes that the firm worked closely with Wausau from the project’s earliest stages. He credits Wausau’s architectural sales representative Brad Glauser as his primary contact in working through the project’s complexities.

“Brad assisted us with selecting the system, and fine-tuning it to achieve the building envelope’s glassine openness and meet the energy code,” says Roll. “With digital modeling, we were able to get inside the units before anything was built to balance where the glass and metal panels should be placed for the right performance and look.”

Bringing the architectural vision to reality, Yorke & Curtis, Inc. served as the general contractor. They broke ground in Jan. 2015 and coordinated the phased construction schedule with Oregon-based glazing contractor Dallas Glass.

photo by Joshua Jay Elliott, courtesy of Works Progress Architecture, LLP

This project was the glazing contractor’s first experience with a unitized curtainwall system. “We loved it,” says Darand Davies, president of Dallas Glass. “I think it went really well for being our first time working with a unitized system. It was rather amazing that, on average, we have just five guys in field who were capable of completing a full floor every two weeks.”

“Using INvision unitized curtainwall, installation time is a fraction of what’s necessary for field-glazed systems. Handling for each unit is minimized, which decreases the opportunity for a mishap and saves time overall,” notes Wausau’s Glauser. “The curtainwall’s interlocking frame design accommodates seismic, live load and thermal building movements. Low U-Factors allow broad expanses of vision glass to meet Model Energy Codes.”

To match Portland’s climate and the project’s goals for energy efficiency and occupant comfort, Wausau’s aluminum-framed products have been thermally improved by Linetec using a polyamide barrier. Combining the thermal barrier with solar-control, low-E, insulating glass from Vitro Architectural Glass achieves the specified performance for low solar heat gain coefficient, low U-Factor, high condensation resistance factor and high visible light transmittance. Seasonal opportunities for natural ventilation also help reduce the demand on HVAC systems and associated energy use. Weather permitting, the operable windows on Slate allow tenants to enjoy fresh air, natural light and views.

Within sight are downtown Portland, the Willamette River, landmark bridges, the West Hills and Mount Hood. According to the City of Portland’s Design Commission, Slate’s design features floor-to-ceiling curtainwall “placed at the most important – in other words, the most visually prominent and functionally significant parts” and “aids in the success of the space by fostering a visually seamless relationship between the building’s interior and the exterior environment.”

“Transmission of unwanted noise is reduced by heavy architectural glass and low air infiltration,” adds Glauser. “Along with the great location and comfortable interiors, tenants also are drawn to the building’s attractive appearance. And building owners and property managers will appreciate the ease in maintaining the window systems’ appearance and functionality.”