Newsletter | Mar/Apr 2005

This Old Conservatory
by Hoi Y. Poon

Rehabilitating an American Treasure in San Francisco's Golden Gate Park


DATE: Tuesday, 19 April 2005
TIME: 5:30 pm
PLACE: Conservatory of Flowers, Golden Gate Park
RSVP to: Mimi Malayan, 510.528.8997 /

In 1995 during one of the worst winter storms on record, 100 mile-per-hour winds tore through San Francisco, toppling countless trees, ripping off roofs and leaving one of the city's most beloved landmarks in tatters. 40% of the glass tiles that once sheathed the Victorian-era Conservatory of Flowers lay smashed on the ground, several wood arches were damaged and a portion of its collection of rare tropical plants was lost. Inspecting the building after the storm, Department of Public Works (DPW) officials despaired to find that the years of extreme moisture both inside and outside the building had rotted the infrastructure extensively. It was clear that something had to be done to save this fragile, decaying glass palace. But what? "This was a totally unique animal," says Edgar Lopez, a project manager for the City and County of San Francisco's DPW Bureau of Architecture. "Here was this pre-fab, one-of-a-kind 19th Century greenhouse and no existing drawings. No one knew how to put the building back together." Indeed little was known about the construction of the building, and its history was clouded with legends.

Records show that James Lick, a wealthy businessman who made his fortune in real estate, ordered the greenhouse for his Santa Clara Valley estate. Unfortunately, Lick died before it was ever erected. Put up for sale by his trustees, the kit was purchased in 1878 by a group of prominent San Franciscans who offered it to the City of San Francisco for use in Golden Gate Park. The gift was accepted by the Park Commission, who hired Lord & Burnham, a greenhouse manufacturing company from New York, to build it. Beyond this, however, the facts become more confused. It is unclear whether the components were shipped from Europe or manufactured in California. Significant use of old-growth redwood in the building's infrastructure supports the theory that some portion of it was constructed here on the West Coast. Some say these sections were lost en route from Europe when they and the heating boiler went down with their ship in a storm. Without any substantial documentation, the rehabilitation team was not even sure the kit would come apart. The decision was made to develop a testing phase, which involved the removal and reassembly of a 900 square foot section of the West Wing. Each component was separated to determine the assembly technique, and the various building materials were analyzed to determine their age, composition and integrity. "Like a dissection," says Jim Kennedy, the project's construction manager. "It was the best way we could think of to guesstimate what would need to happen in the rest of the building."

When the analysis was complete, the team was faced with two key issues that would determine the course of the rehabilitation: what type of lumber to use and whether the building should be put back exactly as it was or built as it should have been. When the three bays of the West Wing were dismantled, it became clear that the building was a hodge-podge of different types of lumber including ponderosa pine, sugar pine, Douglas fir and old-growth redwood. Except for the redwood, these were all decaying at varying rates, particularly the fir. The mullions were especially compromised at the attachment point due to rusting square nails. "It was like amoebas had been eating the wood," says Lopez.

The project's engineers were recommending pressure-treated new growth redwood to replace these rotted pieces, but the City was determined to find a more environmentally friendly material. A suggestion to use recycled old growth redwood was nixed by the engineers, as it would be nearly impossible to determine the structural load. So, the decision was made to use buckskin logs, trees that fall naturally or are abandoned by logging companies. The engineers were only willing to agree to this if each piece was hand-graded to determine its structural strength. The City brought in a pro, Charlie Jordain, who hand-graded each of the 2000 milled pieces, which were also weighed for density and structural integrity. "I think I weighed at least half of those twenty-footers myself," says Kennedy.

Perhaps the biggest decision that the team faced in the rehabilitation project was the question of historical accuracy. In the first phase of the project when the three bays were dismantled and reassembled, the team was determined to replace everything exactly where it had been, imperfections due to structural settlement and all. But midway into the assembly, it became clear to everyone that "as it was" was not as good as "how it should be." The roofline had a wavy look and the glass was misaligned. What's more, the whole thing was off square 2 inches. Discussions began immediately with Christina Wallace, FEMA's representative for federal oversight of preservation. Eventually a decision was agreed upon to group pieces like the mullions with their arch as opposed to replacing each in its exact, original location.

Adding to the complexity of the project was one very old philodendron. The Conservatory's century-old tropical giant could not be moved. Several other very old and valuable species also needed protection from the mayhem. So, in Phase One when the team was reconstructing the three bays, they also tested temporary enclosures for plants. The primary issue was heating. These plants would be irreparably damaged in sustained temperatures of less than 58 degrees. A fin tube heating system was devised, but concern for the plants was so high that four team members including Kennedy, the Conservatory's curator, and two reps from the general contractor wore pagers that would start to beep if the temperature dropped below 58. Once the pagers signaled the team, they had one hour to restore the temperature in the enclosure. "It happened three times," says Kennedy, shaking his head thoughtfully. "During one storm, a eucalyptus came down right in front of us as we were running down the road to the enclosure."

$25 million dollars later, rehabilitation of the Conservatory is winding down, due to be completed on time in September. Soon the $4 million worth of new exhibits will be installed and the plants moved back into their home. "We have created plant heaven," says Lopez, "This building is like my baby -- you can't imagine the sleepless nights! But I'm so proud to be a part of the rehabilitation of a landmark that is so loved by this cityŠto be associated with something so unique and beautiful. I still drive by on weekends and just look at it."


The Conservatory of Flowers has been a San Francisco icon since it was erected in 1879. The 12,000 square-foot Victorian greenhouse is the oldest existing public conservatory in the Western Hemisphere. The rehabilitation of the Conservatory began with spontaneous donations from private citizens after the 1995 storms. Designated as a city, state and national historic landmark, the Conservatory of Flowers is an official project of Save America's Treasures, a project of the National Trust for Historic Preservation. The Conservatory rehabilitation is managed by a partnership between the San Francisco Recreation & Park Department, Department of Public Works, and the non-profit Friends of Recreation & Parks, which is leading the fundraising campaign.

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