ISSN: 1546-962X
Published Online: 30 July 2009
Page Count: 16

Measurement of Water Permeability of Roof Tiles and Influence of Entrapped Air

Iba, Chiemi
Researcher,Hokkaido Northern Regional Building Research Institute,

Hokoi, Shuichi
Professor,Kyoto Univ.,

(Received 18 July 2008; accepted 30 June 2009)

Abstract

Freezing damage in roof tiles is caused by a temperature drop in conjunction with a percent of saturation inside the tile. In order to understand the freezing-thawing process, it is necessary to know the moisture transport characteristics of a roof tile. In general, Japanese roof tiles have surface finishes. In this study, the water permeability of roof tiles with and without surface finishes was measured. The measured results showed that tiles with surface finishes had water resistances a few thousand-fold higher than tiles without surface finishes. Furthermore, it appears that the air entrapped within the tile has a significant influence on moisture transport in the tile. The influence of air was examined by numerical analysis, which demonstrated that an increase in the entrapped air pressure suppressed water infiltration.

Keywords:
roof tile, water permeability, entrapped air, saturation

Paper ID: JAI102030
DOI: 10.1520/JAI102030
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