伝統技能によって施工される材料の熱・湿気特性に関する考察: 兵庫県産左官材料（中塗り土）の評価

摘要

近年まで住宅建材は安価で汎用性のある石油由来の化学製品が大 量に利用されてきた。しかし、これらの建材から放出されるホルムア ルデヒド等の化学物質は住宅の気密性能向上に伴い、アトピーやアレ ルギーといった過敏症を引き起こす原因となり、シックハウス症候群 といった居住者の健康を損ねる社会問題となった。%Mud wall is a collective designation for walls that are constructed with clay and mud using traditional Japanese craft techniques. The mud wall has called Tsuchikabe in Japanese. In order to form Tsuchikabe, a mixture of clay and straw is plastered onto a woven bamboo lath (Komai). In this report, we provide measurements on the heat and moisture properties of the wall. These results enable us to make quantitative evaluations of the heat insulating and moisture conditioning properties of Tsuchikabe constructed using traditional techniques. The materials were collected in Hyogo. Their equilibrium moisture content, heat conductivity and moisture conductivity were measured. The measurement method conformed to JIS and ISO. The measurement results showed that the equilibrium moisture content of Nakanuritsuchi was in broad agreement with that of plasterboard. Moisture conductivity was measured in the range of 25-81% relative humidity, to ascertain the relationship between moisture conductivity and relative humidity. Furthermore, we show the results of the correlation between moisture conductivity and relative humidity. Heat conductivity reached 0.362 (W/m·K) [30.3℃] under air-dried conditions. This indicates that this property has low dependence on temperature and relative humidity and could be therefore treated as a fixed value.