Construction and Demolition Case Study
Presidio of San Francisco, Building 901 Deconstruction
The Presidio of San Francisco is located on the northern point of the San Francisco Peninsula at the South end of the Golden Gate Bridge, and is dissected by Routes 101 and 1. This former military post is now part of the Golden Gate National Park. The lands that constitute this national park extend north to Tomales Bay in Marin County and south to the San Francisco watershed lands in San Mateo. The park encompasses 73,000 acres of land and water.
The Presidio of San Francisco was transferred from the U.S. Army to the National Park Service in 1995. It encompasses 1,480 acres and contains 870 buildings, a research facility, a golf course, and a national cemetery. Of the 870 buildings on site (representing over 6.2 million ft2), 570 have landmark status. The remaining 200 buildings are slated for demolition. The current plan is to demolish 43 of the 200 buildings this year. This first phase of demolition will address the buildings around Crissy Field.
The closure and redevelopment plan for the Presidio intends for the area to be a working laboratory to create models of environmental sustainability. These models could then be transferred worldwide. Under these guidelines, there was recycling language incorporated into the overall demolition contract for the buildings on site. However, the contract did not have high percentage requirements for recycling and did not differentiate reuse, salvaging, and other high order uses from recycling or mulching materials. The mechanical demolition proposed for the first stage of demolition would allow for the minimum recovery but precluded language that gave preference to salvaging the materials for high order uses.
After much debate and lobbying from various interested parties, two buildings were pulled out of the greater demolition contract. Those two structures were buildings 283 and 901 which were located at opposite ends of Crissy Field. The larger of the wood buildings, 283, was a two story timber frame structure that served as a machine shop, storage, and office building. This building was dismantled by the general contractor, South Bay Maintenance, Inc. The other building pulled from the larger contract, building 901, will be the focus of this case study.
The proposed demolition of building 901 would be done in a fashion that would salvage and recycle as much materials as possible. As a result, the demolition would involve a great deal of hand dismantling and salvaging of materials and will serve as an excellent basis for case studies.
Building 901 is located on the west side of Crissy Field. It is a one-story wood frame building with floor dimensions of approximately 60' x 135'. It was constructed in 1942 as a "temporary" wartime structure. The building served as a warehouse with office space added to a portion of the interior at a later date. The building was constructed almost entirely of wood, with wood siding, wood flooring on concrete supports, and wood slat roofing boards covered with a recent reroof of asphalt shingles.
The deconstruction and salvaging of materials was performed by a consortium of representatives from three salvaging groups. Participants in the hand deconstruction activities included: Beyond Waste, a Sonoma based deconstruction partnership, whose business manager is Pavitra Crimmel; San Francisco Community Recyclers, a nonprofit organization involved in recycling services and education in the conservation of resources directed by Kevin Drew; and Wood Resource Efficiency Network, an Oregon based conservation research endeavor coordinated by Phil Kreitner.
The intent of the 901 project was show the amount of materials that can be salvaged using soft demolition techniques, while performing the operation at costs competitive with traditional demolition operations. The materials will be salvaged to the greatest extent possible and sold to the group(s) with the highest bids.