民家建造物における伝統的な塗装材料の調査と修理: 重要文化財小野家住宅主屋における塗装修理の施工例

摘要

The present paper is a report on the observation and analysis of traditional coating materials used on Japanese folk architecture and its application to the restoration of coatings. Study by observation of the Ono family house at Shiojiri, Nagano prefecture revealed that most of the wooden members of this architecture are covered with some types of coating material, especially with urushi which is very lustrous. The coating methods used were identified as shunkei-nuri, black urushi coating, black coating, bengala coating, and suri-urushi or fuki-urushi. Next, elemental analyses including those using a microscope, PY-GC/MS and X-ray fluorescence, as well as cross-section analysis by observation were conducted on small pieces of coating layers. As a result it was found that although the coated surface might appear quite lustrous, not all was coated with urushi. On some surfaces dried oil had been used, while on others new materials, such as varnish or wax, had been used. There were even places where the surface had been polished by constant wiping. Based on these findings, it was decided that, to restore the coated surfaces of the Ono family house, urushi coating would be applied only to places where analysis had clearly shown urushi coating, while for other places boiled dried oil would be used to wipe the surfaces.%以上，本稿では近世に建造された民家建造物である小野家住宅主屋内部の塗装材料について目視観察および分析調査を行い，塗装修理の施工仕様に反映させるよう努めた。まず小野家住宅主屋内部の各部屋の柱や長押，鴨居，階段手摺，壁板，床板など，ほとんどの建造物を構成する部材には何らかの塗装，とりわけ艷光沢が良好な漆塗装が施されているように観察された。これらは春慶塗，黒漆塗，墨塗り，弁柄塗り，古色塗りと類似した塗装，などに目視分類されたが，分析用の小破片試料の採取が可能であった箇所については，さらに分析調査を行った。