Chiemi Iba

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

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.

Moisture characteristics of water-repellent consolidants and their applicability to existing buildings

Water-repellent agents are considered an effective measure of preventing moisture damage in building materials. However, data on the moisture transfer characteristics of repellent materials are insufficient. This study focused on the transfer of liquid water in a porous building material and quantitatively evaluated the applicability of a water-repellent consolidant as a protection agent via water infiltration experiments and numerical analysis. The experimental results could be reproduced by treating the water-repellent consolidant as having two layers with different water conductivities.

Field survey on frost damage to roof tiles under climatic conditions

Purpose – Frost damage is well-known as the main cause of roof tile deterioration. The purpose of this paper is to develop an analytical model for predicting the deterioration process under certain climatic conditions. This paper describes the results of a field survey conducted to acquire fundamental information useful to this aim. Design/methodology/approach – A field survey of roof tile damage by freezing was conducted in an old temple precinct in Kyoto, Japan. Using detailed observations and photographic recordings, the damage progress was clarified. To examine the impact of climatic conditions upon the damage characteristics, weather data and roof tile temperatures were measured and logged in the winter season. Findings – The deterioration process was observed under the climatic conditions associated with the measured temperature of the roof tiles. In particular, it was revealed that the orientation has a significant influence on increasing or decreasing the risk of frost damage. For certain distinct...

STUDY ON MOISTURE TRANSPORT OF ROOF TILES WITH SURFACE FINISH

Freezing damage in roof tiles is caused by a temperature drop in conjunction with an increase in water content 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 was shown that the air entrapped within the tile has a significant influence on moisture transport in the tile. By infiltration experiments both in the laboratory and the under the outdoor condition, the characteristics of water infiltration into the tiles were also clarified.