by Jason King
One of the most exciting projects currently on the boards at TERRA.fluxus is the green roof design for the Van Ness Medical Office Building in Downtown San Francisco. This 10,000 square foot project includes multiple levels of green roof meant for visual access from within the building. Jason King initiated project (originally through GreenWorks) and has continued with TERRA.fluxus through a collaboration with roofing manufacturer Tremco and contractor Lawson Roofing to facilitate the design consultation with owner and design team including architects at Boulder Associates, who have been the main collaborators on the design to date.
The concept plan below shows the three roof levels, including the 2nd, 6th, and 7th floor roofs, all of which contribute the overall aesthetics as well as to provide stormwater management to meet local stormwater guidelines and contribute to multiple LEED credits.
It was determined that a 10″ deep profile was necessary to provide adequate stormwater management. Instead of a monolithic section of soil and plans, it made sense to create undulating berms. These created a number of micro-habitats for different plant species, while also encouraging rooftop fauna in the form of birds, insects, and other desired species whose habitats have been displaced through urbanization. In addition, these waves improve the overall conceptual idea of waves of vegetation that would move in the breezes and break up large expanses of roof – providing a variety of interesting views from all angles.
Early on, a number of precedent images were presented to outline the concept and develop consensus for the group. The following shows a particular study in the landform manipulation, which became a significant point of departure for the design concept for roofs on the 2nd and 6th Floor.
The plant palette consists of a combination of California native species, including grasses, perennials, succulants, and other species adapted for low-maintenance and minimal water usage per LEED requirements. The 7th floor roof included a deeper planter that accommodated larger woody materials including shrubs and small ornamental native trees.
A number of sketchup images also provided design studies and allowed for the design concept to be coordinated with perimeter pavers, rooftop mechanical equipment, drains, and other elements to ensure the interface between building and vegetation was seamless.
The concept of design-build for green roof projects offers many benefits, particularly in green roof projects. The interrelationship of landscape and building in this case required close coordination between contractors and designers to ensure compatibility with a number of project goals. Decisions made could impact LEED credits, waterproofing membrane integrity, or constructability – this a close group effort was necessary to make sure myriad issues were resolved.
The project is progressing through Construction Documentation phase, and is slated for construction beginning in 2011, with green roof scheduled to be installed in 2012. This addition to the skyline of San Francisco, and the growing collection of Bay-area green roofs will be an amenity from adjacent buildings, MOB users, and area wildlife for years to come.
[project credits Jason King, design work completed while working at GreenWorks PC]
