Green Innovation Award: What's Old is New Again

It’s much easier to start fresh.

Group Mackenzie, a Portland architecture firm, won GreenSmart’s Best of 2007 Green Renovation award for the redesign of an old warehouse in Portland into a RiverEast Center. The project successfully balances and integrates often-competing goals, including retaining the industrial character of the existing structure; creating comfortable, productive office spaces; and maximizing sustainable design principles.

Group Mackenzie’s engineers and architects took the original 1951 concrete warehouse located in Portland’s central eastside and redeveloped it as an office building for 250 creative professionals, seven businesses and two non-profits. The $17 million project was financed through a limited liability company by the leaders of Group Mackenzie and Coaxis Software, two major tenants in the building.

The building’s sustainable features were kept to less than 5% of the total budget. The project team was able to retain 100% of the original structure, including the south entrance façade, 20-ft ceilings and columns.

The sustainable design of the building successfully reduces energy consumption beyond code requirements and features a unique solar wall on its south side. To maximize the use of natural light, concrete slabs were cut out of the building’s exterior walls and re-used as part of the landscape design. Recycling efforts contributed to more than 95% of the construction waste being recycled, minimizing the impact on landfills.

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Project Team
Developer: Rivers East, LLC
Architect/Engineer: Group Mackenzie, Portland
Contractor: Howard S. Wright, Portland
Construction Manager: GVA Kidder Matthews, Portland
Mechanical, Electrical and Plumbing (MEP) Engineers: Interface Engineering, Portland
Landscape Architect: GreenWorks, Portland

Building challenges

The building, formally the Holman Transfer Building, served to store and transport boxes and crates for companies like Quaker Oats and Coca-Cola. The concrete building stood largely vacant for 40 years.

Problems in the building included poor seismic conditions, a significantly sloped floor and asbestos.

There also was an existing building tenant, the Portland Boathouse, which uses a small space as storage.  Additionally, the Oregon Department of Transportation owns the land underneath the building, because of its adjacency to I-5.

Jeff Reaves, president of Group Mackenzie, saw potential in the building with its close-in downtown location, architectural details and an opportunity to showcase the architect and engineering firm’s commitment to sustainable design.

One of the design team’s goals for the project was to retain the building’s original structure. At the same time, the team’s structural engineers had to make updates to the building to meet current seismic codes, interior designers had different visions for each tenant space and the architects had their eye on LEED gold certification.

Countless meetings and negotiation among the different disciplines and contractors were required to move through the multitude of functional, aesthetic and economic decisions.

Heating and Cooling

The team found ways to earn LEED credits by using the existing building shell. Retaining 100% of the original structure not only counted toward the reuse of materials, but the existing thick concrete walls help modulate temperature differences and reduce heating and cooling costs.

The south side of the building was unprotected from the sun, a liability that the designers turned into an asset by converting it into a dynamic solar wall that uses a system of glass panels, baffles and shelves to alternately capture and divert solar heat throughout the seasons.

The wall has four distinct functions, including collecting heat that is used to preheat air into the building’s mechanical systems; acting as an effective insulation buffer between inside temperature and outside air (averaging a 19% difference); keeping the building cool during the warm months by flushing out collected heat directly up through vents to the outside air; and blocking harsh solar rays.

To make it work, structural engineers had to determine how to secure the wall to the building; architects were concerned with its design aesthetic compared to the industrial nature of the rest of the exterior and interior of the building; lighting designers focused on the quality of light; mechanical engineers worked to integrate the envelope into the HVAC system; and energy engineers ran models to determine the impact with and without the envelope.

In addition to the solar wall, passive heating and cooling strategies are used to condition non-regularly occupied spaces, such as the boathouse and the main lobby. During the summer months, the lobby is precooled at night through a relief hood at the top of the space.

The solar wall, together with a wide use of natural light, a reflective white roof on the building, special glazing and energy-efficient fixtures cuts energy use.

Stormwater Treatment

Portions of the exterior wall that were removed to introduce natural light and capture views of the river and downtown were reused onsite by grinding the concrete for use as structural infill. Large, monolithic slabs were saved and utilized by local artist Linda Wysong as sculptures in the plaza.

Recycled concrete was also used in the building’s stormwater system, designed by Group Mackenzie’s civil engineers and the landscape architects of GreenWorks PC of Portland.

Typically, urban redevelopment projects are obligated only to treat new impervious surface at ground level. RiverEast Center’s system, which received a grant from the City’s Bureau of Environmental Services, is a demonstration project for collaborative stormwater treatment. The system treats runoff from the building’s roof, parking lot, public plaza and adjoining city streets.

The stormwater system starts on the building’s roof, which is sloped so rainwater can travel to the artistic scuppers located on the south end. Catch basins next to the building collect stormwater from the roof and filter it through flow-through planters made of recycled concrete slabs and native plantings.

Parking lot landscape areas with native plantings capture and clean runoff from the public streets and the private parking lot. The facility combines a standard flow-through planter and infiltration basin, creating a storm system that cleanses stormwater and meters flow into the Willamette River. The RiverEast Center system reduces the load on the city’s overworked sewer system and naturally filters runoff.
The double envelope solar wall at the RiverEast Center is a good teaching example for other developers. The shared green street, which required a lengthy process to draft a shared-use agreement for stormwater, now serves as a guide for future projects.