JAUE2014-054 Survey on Eco Housing in Bungotakada City, Oita Prefecture Study on the possibility of condensation in the under floor space with a mat foundation and vent holes in rainy season

Abstract

This study, aims to identify the conditions and causes of condensation with mat foundation and floor insulation. Humidity under the floor shows that at Eco House with mat foundation and floor insulation during the 2011 rainy season, more than 70% of the time the humidity exceeds 100% the entire day, and condensation is a constant condition. We stopped the vent holes in the foundation to prevent outdoor air from entering the under floor space. Therefore, the under floor humidity became stable due to the sealing. However, the humidity level reaches 100% finally because the mat foundation and floor insulation prevents air ventilation between rooms and the under floor space. Also in the housing center, houses A and B with mat foundation and foundation insulation have much lower humidity measurements. When A and B are compared, the humidity in house A is lower than B. Because under floor humidity levels of house A that allow ventilation between rooms and the under floor space.
Therefore, it is necessary to use foundation insulation for an airtight under floor space, and allow sufficient ventilation between rooms and the under floor space, in order to prevent summer condensation in modern houses during the rainy season.