architectural history of the conservatory

Conservatory of Flowers Updated: 6/16

Architecture, Artists and Masons

Architectural History of the Conservatory

The Conservatory of Flowers is 240 feet long, 12,000 square feet and the upper dome stands 55 feet up from the ground. A total of 8,000 panes of glass make up the main building. Most of the ornamental colored glass is original. The structure was originally constructed of douglas fir, sugar pine and redwood. The original Conservatory was constructed of 80% old-growth redwood; the new Conservatory is 75% old-growth redwood. Old-growth redwood was chosen:

because of its durability (so as to minimize the constant need for repair and replacement of materials), and

to match the original construction materials of the Conservatory (in accordance with the Secretary of Interior’s Standards for the Treatment of Historic Properties).

No living redwoods were destroyed for the restoration. The wood was retrieved from “buckskin” logs, trees which fell naturally, standing stumps, or commercially felled trees that could not be retrieved economically.

Where were the plants during the restoration?

The plants were moved to the adjoining support greenhouses. Six of the largest plants were housed at a facility near Hunter’s Point. When the west wing of the Conservatory was completed, many of the larger plants from the dome were moved there while the Dome underwent restoration. The 100-year-old philodendron in the dome was the only plant that remained in the ground. The Philodendron speciosum (Phil), Phoenix roebelinii (pigmy date palm) and Dioon spinulosum and Zamia lpoeppingiana (cycads in Lowlands) were equipped with a custom-made greenhouse while construction occurred around them.

Why was the Conservatory rehabilitated with wood instead of aluminum or galvanized steel?

Wood is more resilient to seismic activity than metal, and wood served the Conservatory very well for well over a century. It was also necessary to use wood in the rehabilitation process to maintain the historical designations.

The upper dome of the Conservatory weighed about 29,000 pounds when it was craned onto the lower dome on January 10, 2003.

Seismic upgrades to the structure include a more substantial foundation, stainless steel plates inside many of the arches, and safety glass.


The Conservatory of Flowers is 12,000 square feet in size; the dome is 56 feet in diameter and 55 feet tall; each wing is 95 feet long and the galleries are 35 feet wide and 19 feet to the ridge or peak.

The finial atop the dome is 13 feet tall and weighs about 800 pounds.

The Conservatory’s original walkways were gravel, then wood and subsequently concrete - formed from one of the oldest concrete pours in the West. One of the original concrete patent stamps has been reinstalled adjacent to the threshold between the dome and west wing (concrete patent date of 1882).

What is the apical ornament of the current finial and what is its significance?

Saturn: in Roman mythology he was the god of seed sowing.

What was the original apical adornment?

An eagle.

Which parts of the dome are not original to the 1879 design?

Upper dome, clerestory, and finial adornment

Why is it White?

Glass greenhouses were traditionally whitewashed to moderate the heat inside and the amount of sun that the plants receive. Generally, a film of whitewash is applied in the spring to protect plants during the summer when the sun is at its hottest. The whitewash starts to thin and become more transparent as it washes away with fall rains, allowing more light into the building as the days grow shorter and light intensity wanes. In a foggy city like San Francisco, the Conservatory’s plants would never be in much danger of burning, especially not with the modern glass panes that were installed during the recent restoration. But city officials felt strongly that the building remain as historically accurate as possible and so, the whitewashing tradition continues to this day.


Condensed Architectural Timeline

1872 Lord & Burnham structure purchased by D.O. Mills (a trustee of Lick’s); bears

resemblance to Conservatory of Flowers

1876 James Lick dies; Conservatory, in crates, among his effects

1878 Conservatory erected

1879 Conservatory opens

1883 Palm Room fire; dome reconstructed, second mechanical basement likely added

at this time; clerestory added to increase height of the dome by six feet

1918 Fire; repairs were made as needed, not thoroughly documented

1933 Conservatory closed, structurally unsound, reopening date unclear

Post WWII Some structural elements and woodwork replaced

1959 Wood windows (side vents) at base of glazed walls in-filled with concrete –

caused poor ventilation – cast to match profile of original construction

1964 - 65 Clerestory of dome reconstruction, columns, lintels, and sills replaced with

redwood; 500 lineal feet of cap molding covering arches replaced

1978 - 82 Major repairs on deteriorated woodwork (distinct from 1960s zone of work)

1995 Major storm damage; Conservatory closed

2000-2003 Renovations


Tami Stewart, Bay Area model-maker/fabricator The tree is constructed from a welded steel armature and styrofoam- coated in a durable, moisture proof cemetaceous material textured to resemble bark, painted with acrylics and clear coated. The orchids and insects are metal armature covered in felt, epoxy, acrylic paint.

architectural history of the conservatory

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