Reconstruction
Because of the long periods of abandonment and numerous renovations, many details are disputed amongst scholars, such as the exact layout of the original grotto, the buildings in Bulguksa or the shape of the watercourse, which no longer exists, in front of the temple.
Repair and improvements were undertaken in 1703 and 1758, during the Joseon dynasty, however the Confucian-oriented rulers tended to suppress Buddhism and the remote mountain grotto was seriously damaged by the turn of the 20th century. The Government-General of Chosen conducted restoration works three times, but faced humidity and other problems.
Japan did the first round of repairs from 1913 to 1915. These repairs were conducted without sufficient study of the structure of the grotto. During Japanese cleaning efforts, the structure of the grotto was almost completely dismantled and reassembled. A major mistake committed by the Japanese was their attempt to stabilize the structure by encasement in concrete. This resulted in humidity buildup and in water leaks, and caused erosion of the sculptures, because the grotto could no longer "breathe." In 1917, drainage pipes were buried above the dome to channel rainwater away from the grotto. However, as leaks continued in spite of the pipes, another round of repairs was conducted from 1920-1923. Waterproof asphalt was applied to the surface of the concrete, which only worsened the problem. Moss and mold formed, and in 1927 the now unthinkable method of spraying hot steam was used to clean the sculptures.
After World War II, in the 1960s, President Park Chung Hee ordered a major restoration project. The problem of temperature and humidity control was resolved to an extent by using mechanical systems. The wooden superstructure built over the antechamber remains a subject for debate for many historians who believe Seokguram originally did not have such a structure blocking the view of the sunrise over the ocean, and cutting off the air flow into the grotto.
The interior of the grotto can now only be viewed through a glass wall, installed to protect it from the large number of tourists it attracts, as well as temperature change.
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