100 John F. Kennedy Drive, San Francisco,California
Year Constructed
Year Retrofitted
Structural Engineering Firm(s)
  • Tennebaum-Manheim Engineers
Structural Engineer(s)
  • Nancy Tannenbaum
Architecture Rsources Group
Conservatory of Flowers Landscape
Conservatory of Flowers Landscape
Conservatory Interior - Water Lilies
Conservatory Interior - Water Lilies
Potted Plants
Potted Plants
Structure & Architecture
Structure & Architecture
Significance to Structural Engineering History in Northern California

The Conservatory of Flowers has captivated guests for more than a century. This gem of Victorian architecture has a long and storied history, and is the oldest public wood-and-glass conservatory in North America. As a city, state, and national historic landmark, the Conservatory remains one of the most photographed and beloved attractions in San Francisco.

The precise origin of the Conservatory of Flowers is shrouded in mystery, but the story begins with James Lick, a California pioneer who made his fortune in real estate. He also practiced horticulture, and in the early 1870s, ordered two conservatories for his estate in Santa Clara. Although accounts conflict, he likely commissioned the structures from Lord and Burnham – the preeminent American manufacturer of conservatories until the company shuttered in the 1980s.

The material for the 12,000 square feet (1,100 m2) conservatory modeled after Kew Gardens in London was originally bought in 1876 by James Lick, an eccentric businessman, piano maker, and successful real estate investor who was a patron of the sciences. It is believed that Lick purchased the materials from Lord & Burnham, a manufacturer of greenhouses located in upstate New York, and these were sent in kit form, to be assembled on site. The order is said to have been the company’s first big sale. The 33 tons of glass were sent by boat – most probably one chartered by Lick – from New York, around Cape Horn to San Francisco Bay.

James Lick died on October 1, 1876. After his assets were distributed to specified beneficiaries, including many charitable causes, the remainder of his estate was divided between the Academy of Sciences and the Society of California Pioneers. The latter received crates of glass equaling 33 tons: Lick’s unconstructed conservatories. In 1877, the Society of California Pioneers sold the conservatories to 27 prominent San Franciscans and local philanthropists, including former Mayor William Alvord, Charles Crocker, Leland Stanford, and Claus Spreckels. It was the intention of these men to donate the conservatories to the City of San Francisco, for public use in Golden Gate Park.

The Park Commission formally accepted donation of the Lick conservatories on January 2, 1878. The Commission hired Lord and Burnham to build the Conservatory, since the crates allegedly included plans already drawn up by the company. Founding partner F.A. Lord came to San Francisco to personally oversee the project. The specific architect of the greenhouse is not known for certain. The San Francisco Public Library holds a document entitled Information about Samuel Charles Bugbee, written by a relative, Arthur S. Bugbee, in 1957. It indicates that the architect Samual Charles Bugbee, whose works included the homes of Leland Stanford and Charles Crocker and the Mendocino Presbyterian Church, may also have designed the Conservatory of Flowers. One engineer, Joseph Paxton (1803–1865), had an enormous effect on the development of the conservatory building type. His structures called for a system of glass and metal roof construction, whereas past structures had typically been constructed of wood and glass. His choice of materials allowed designs for glasshouses of substantially larger scales. Significant use of old-growth redwood and other native trees in the building’s infrastructure indicate that some construction materials were locally sourced. A stipulation of the donation was that the Conservatory be erected within eighteen months, and it was constructed incredibly quickly, in spite of the shipwreck of the steamer Georgia, which was carrying over $1,000 of the Conservatory’s construction materials. This may explain why the Conservatory does not seem to have a formal opening date, but rather a soft opening sometime in the middle of April 1879.

The 12,000 sf conservatory is 68 feet high. The central architecture feature of the building is the 57 feet square, Victorian style, glass dome. The original configuration of the interior spaces included a fountain in the entryway and another in the Palm Room, under the dome. The west wing displayed flowering and ornamental foliage in one gallery and hard wooded plants, like azaleas, in the other. The east wing featured the Orchid House and an aquatic plant gallery with a large pond, which contained the Conservatory’s first blockbuster exhibit: the Victoria regia. This giant water lily, with leaves that grow several feet in diameter, was the first of its kind to be grown in California, and brought both recognition and crowds to the Park.

During the restoration after a 1883 Conservatory fire, the dome was raised by six feet and the eagle finial on top of the dome was replaced with the planet Saturn, likely a reference to the ancient Roman god of agriculture. In 1895, the Conservatory received electricity for the first time when a motor was installed that helped to regulate temperature. Although the 1906 Earthquake and Fire brought devastation to San Francisco, the Conservatory was relatively unharmed.

Tennebaum-Manheim Engineers was the Prime A/E Professional in association with ARG (Architect) and won numerous awards for a unique and sensitive 1998 – 2002 Conservatory Restoration and Structure upgrade.

The A/E team prepared the Conservatory of Flowers Complex in Golden Gate Park: Historic Structures Report. Rehabilitation followed sustainable design practice including incorporating structural wood member replacement with fallen redwood timber. Valuable plants that remained in place, were protected and surrounded with temporary enclosures and the upgrade structure was built around them.

Structure Description

Originally constructed in 1878, the Conservatory of Flowers is the oldest building in San Francisco’s Golden Gate Park. It was closed for a six-year restoration. The effort, led by Architectural Resources Group, included conservation, restoration, rehabilitation, lateral strengthening, and new mechanical and electrical systems. The H

Between November 1996 and January 1997, on-site surveys were conducted by a project team consisting of Tennebaum-Manheim Engineers and Architectural Resources Group. Surveyors included architects, materials conservators, architectural historians, structural engineers, mechanical engineers, and electrical engineers. The architectural and materials condition survey included a close-range visual inspection of all of the wood members in the building to determine locations of deteriorated wood, an analysis of the types of wood species occurring in the building, a study of the building’s construction details, glazing, and a photographic survey. The structural survey included measuring the deflection of each of the arches and studying the probable lateral and vertical load paths to determine areas of weakness.

The deterioration of wood occurred at typically vulnerable areas, such as the exposed end grain of arches and muntins and where wood members intersect. The humidity in the building was a contributing factor to wood deterioration. The level of moisture in the building was exacerbated by two conditions. First, the building’s natural ventilation system had been removed in a past repair. The ventilators, which were originally located in the low wall area, had been filled in, and some ridge ventilators were inoperable.

In the process, the entire building was taken apart and reassembled, and every one of the thousands of clear-glass panes was replaced. The construction sequence was as follows. First, temporary protection for those plants that could not be moved was provided. Then, the glass was carefully removed from the building, and historic glazing was salvaged. Structural wood elements of the building (arches), as well as muntins that held the glazing, were disassembled. The location of each element was recorded for reinstallation. The lead-based coatings were stripped from the wood members. Each wooden piece was then tested for its strength and determined if repair or replacement was appropriate.

The wood arches that support the Conservatory building were thinned down slightly to allow steel plates to be spliced in, significantly strengthening the structure. The dome was built on the ground and lifted onto the building within a 1/16” erection tolerance.

  • 2005 AIA Institute Honor Award for Architecture
  • 2005 AIA San Francisco Chapter, Excellence in Architecture
  • 2005 California Preservation Foundation, Preservation Design Award, Rehabilitation (Large Projects Category)
  • 2004 State of California, Governor’s Historic Preservation Award
  • 2004 Structural Engineers Association of Northern California, Excellence in Structural Engineering Award to Tennebaum-Manheim Engineers