- Landscape Architecture
- Green roofs and eco-roofs
In a city that requires green roofs on commercial buildings of a certain size, a new eco-roof on Portland, Oregon’s historic city hall underscores the city’s green building policy and demonstrates its commitment to sustainability. The eco-roof design was approved by the Historic Landmarks Commission as compatible with the 1895 building’s historic appearance which includes elevated views from surrounding office towers and a foreground to the Portland Building.
Mayer/Reed developed design alternatives ranging from a meandering meadow – evocative of the native savanna landscapes of the region – to designs with a more formal character. The approved design is a simple, symmetrical layout of eco-roof panels that frame a thin carpet of colorful, textural succulent plantings.
As part of an architect-led roof replacement and exterior surfaces renovation, Mayer/Reed designed the eco-roof to be economical and low maintenance, while maximizing ecological and aesthetic benefits. The team worked with structural engineers to ensure that the thin profile cinder system would meet structural requirements. The panels are placed only over those areas that can withstand the saturated weight and that avoid roof-top mechanical systems.
Changes of the seasons are evident throughout the year. Even though it is called a “green roof,” the color spectrum ranges widely from green to amber to red. Plantings include a mix of twelve drought-tolerant species of sedum and flowering bulbs such as Allium.