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Zoomazium at Woodland Park Zoo

Landscape Performance Benefits


  • Captures 29.9% of all rainwater that falls on the vegetated roof, according to 2 years of monitoring data from Seattle Public Utilities.
  • Reduced impervious surfaces on the site by 15% by incorporating an 8,300 sf green roof and landscape areas. Replacing the roof area of the former primate exhibit with the vegetated roof of the Zoomazium also reduces the urban heat island effect.


  • Increased zoo visitation by 15-20% with significant increases during the wetter months, according to zoo staff.

At a Glance

  • Designer


  • Project Type


  • Former Land Use


  • Location

    601 North 59th Street
    Seattle, Washington 98103
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  • Climate Zone

    Warm-summer Mediterranean

  • Size

    8,800 sf

  • Budget

    $3 million

  • Completion Date


By integrating a successful patch of the native Pacific Northwest temperate forest ecosystem on the roof, Zoomazium demonstrates a new paradigm for interactive exhibit space that is sustainable, adaptable and flexible. Nestled in Woodland Park Zoo’s lush vegetation, it is a place for children to forge life-long commitments to animals, our shared habitat and the planet. This approach helped to make Zoomazium the first LEED Gold zoo building in the world.


The zoo wanted a sustainable new building that would demonstrate its commitment to ecological responsibility and reinforce its systems-based approach to education and its Pacific Northwest biome concept for the zoo visitor experience. Though a green roof was a consideration, there were few successful precedents on which to base design and plant selection.


Zoomazium helps the zoo achieve a range of goals from reducing stormwater runoff, mitigating the urban heat island effect and creating habitat to educating new generations about how to build respectfully. The building and vegetated roof reflect and support the Zoomazium’s education programs on sustainable forest practices.

  • Locating the Zoomazium on the footprint of the old primate house limited site disturbance. Adjacent vegetation was preverved, including a champion black cherry tree.
  • The 8,000-sf “floating forest floor” of over 22,000 native plants on the roof of a new education-focused building enhances Pacific Northwest forest habitat. Species such as Salal and Kinnikninnick are critical components of the forest floor habitat, connecting the Zoomazium to the larger zoo landscape.
  • Local pumice was used in the roof planting medium and a 6” depth was chosen to allow for better water retention and more diverse plant selection.
  • Choosing self-sowing native plants, like lupine and nodding onion, helped the roof vegetation establish quickly.
  • A study was done to map areas of the roof that receive shade from adjacent mature trees. Shade-adapted vegetation, like salal and sword fern, was planted in these areas.
  • No permanent roof irrigation system was installed. Staff hand water when needed.
  • Because bird strikes on windows were a major concern, the fritting was selected through extensive research with ornithologists. No bird deaths have been reported.
  • 72% of wood used in the construction is Forest Stewardship Council (FSC) certified.
  • The roof is the subject of ongoing monitoring and research , which has contributed to local understanding of greenroof systems and appropriate native plants.

The decision to substitute the vegetated roof for a standard metal roof added $150,000 to the total project cost, averaging out at an additional $19 per square foot. This cost includes the installation of structure required to support 6” of planting medium and an increased density of installed plant material.

  • Active maintenance is required, particularly during plant establishment.
  • The roof slope, planting medium, and sun exposure greatly affect water availability during periods of drought.
  • The green roof coir blanket, used to reduce weeds and stabilize lightweight soil, was not soaked prior to installation; as a result, water was observed sheeting off rather than passing through it.

Project Team

Client: Woodland Park Zoo

Prime Consultant/Landscape Architect, Architect, Planner: Mithun, Inc. 

Exhibits: AldrichPears Associates

Design and Fabrication: Dillon Works!

Green Roof System: American Hydrotech

Mechanical and Plumbing: Flack + Kurtz

Natural Daylighting Consultants: BetterBricks Daylighting Lab

Energy Use Consultants: Hultz/BHU/Cross Engineers

Contractors: Kirtley-Wall Associates LLC

Role of the Landscape Architect

Integrated design team member from the beginning of the project through completion.



Stormwater management, Educational value, Native plants, Local materials, Green roof

The LPS Case Study Briefs are produced by the Landscape Architecture Foundation (LAF), working in conjunction with designers and/or academic research teams to assess performance and document each project. LAF has no involvement in the design, construction, operation, or maintenance of the projects. See the Project Team tab for details. If you have questions or comments on the case study itself, contact us at email hidden; JavaScript is required.

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