The purpose of this study is to retrospect the establishment process of specification of modern factory-made traditional Korean roof-tile. Its another purpose is to analyze the specification of watong(瓦桶, a wooden molding frame for roof tile making) which is recorded in the literature of Joseon dynasty. The results of this study are as follows. : First, the specification of modern factory-made Korean roof-tile that currently used was established in 1978. And it did not succeed old traditional specification. Second, in case of construction or repair of main building of palace, it was a principle to use Daewa(大瓦, the big size roof-tile). And Sangwa(常瓦, the ordinary size roof-tile) was used when needed. Also, Jungwa(中瓦, the middle size roof-tile) was used regardless of the size of group building. And Sowa(小瓦, the small size roof-tile) was used in house and wall of royal tomb. Third, it is needed to establish a specification of traditional handmade roof-tile based on the specification of watong through research of the litterateur. So, a standard draft for this was proposed. Finally, one can find the significance that this study has tried to find a specification of traditional roof-tile that can be applied to construction or repair of cultural heritage.

The Sungnyemun roofing tiles were twice disassembled for maintenance work, in 1963 and 1997, and modern tiles were applied in 1997. However, besides differing in visual appearance, the modern tiles had distinctly different physical properties. A study has been carried out on 22 different tiles, including original Sungnyemun tiles, modern tiles applied during maintenance, traditional tiles made by tile-makers, and others, to examine their physical properties, such as bending strength, frost resistance, absorption, whole-rock magnetic susceptibility, chromaticity, differential thermal analysis, and other characteristics. Since the method of making modern tiles involves compressing clay in a vacuum, modern tiles showed relatively greater bending strength and specific gravity, while Sungnyemun tiles and those made by tile-makers, in comparison, demonstrated less bending strength and specific gravity owing to their production method of 'treading,' in which clay is mixed by having someone tread upon it repeatedly. Over time, the absorption rate of the original tile used for Sungyemun gradually decreased from 21% to 14.7%; traditional tiles from tile-makers showed absorption rates of 17%, while the absorption rate of modern tiles was just 1%, which is significantly low. As for frost resistance, Sungnyemun tiles and traditional tiles from tile-makers showed cracking and exfoliation after being subjected to testing 4 or 5 times, while slight cracking was seen on the surface for modern tiles after 1ngy, or 3 times. In other words, no significant difference from influence by frost was found. According to the results of differential thermal analysis, the plastic temperature was shown to have been no less than 1, on℃ for all types of tile, and cristobalite was measuredthrough XRD analysis from a Sungnyemun female tile applied during maintenance in 1963, which appeared to have been plasticized at between 1,200℃~1,300℃. Based on these research results on the physical properties of tiles from the Sungnyemun roof, a fundamental production method for tiles to be applied in the restoration of Sungnyemun has been identified.