the public. Statistics The conservatory has 16,800 window panes. The upper dome of the conservatory weighs 14.5 tonnes. Langley's San Francisco Directory for the Year Commencing April 1879 discussed the construction of the Conservatory of Flowers: The whole building required in its construction twenty-six thousand square feet of glass weighing twenty-five tons, and two tones of putty. It is a marvel of architectural beauty, surpassing in this respect any similar construction in the United States, and is only equaled in size by the Government Conservatory of in the Horticultural Gardens at Washington. Repair campaigns Through its life, the Conservatory of Flowers has undergone several repair campaigns. The Palm Room, located in the center of the building, was seriously damaged in a fire in 1883. Its dome was completely reconstructed at this time. It sustained little damage following the 1906 earthquake. After a second fire damaged the structure in 1918, repairs were made as needed but were not thoroughly documented. No significant documented repairs to the building took place again until sometime after World War II, when certain portions of the wood work, including structural elements, were replaced. In 1959, wood windows at the base of the glazed walls at the building's perimeter were infilled with concrete panels that were cast to match the profiles of the original construction. In 1964-65, the clerestory of the Palm Room underwent reconstruction. The columns, lintels, and sills in this area were replaced by pressure-treated redwood. Five hundred lineal feet of the exterior cap molding, which covers the arches, was replaced at this time as well. Between 1978 and 1982, major repairs were performed on deteriorated woodwork. The areas that were repaired during this time did not overlap the 1960s' repairs to the clerestory. In general, it appears that after 1914 most maintenance work was undertaken only when conditions presented a safety hazard, mechanical systems were in need of repair, or the building became extremely unsightly. Lack of scheduled maintenance affects the performance of building materials. Wood, in particular, requires proper maintenance of paint coatings to control the development of rot. In this building, it is important to maintain the condition of the interior, as well as exterior, coatings because of the humid indoor environment. Also necessary is the maintenance of waterproofing details, such as flashing, to prevent water from accumulating in concealed areas. It is therefore not surprising that rot developed in the building,