A Study on Weatherability of Stain Layers on Timber Used for Traditional Taiwanese Buildings

• Main Authors: LIAO TSAI LUNG, 廖彩龍
• Other Authors: 陳昶良
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/51374836554329417814

碩士 === 中國科技大學 === 建築研究所 === 96 === For timberwork, staining has multiple functions, e.g., decoration, protection and preservation. Further, staining has its inherent craftsmanship and cultural values. Stain layers deteriorate when they age naturally and if the quality of the material used is poor. In this case, staining will fail to protect the timberwork and will adversely affect the exterior of a traditional building. What will be more serious is loss of the cultural values. Therefore, it is very important to understand weatherability levels of staining material with an aim of helping to conserve, restore and protect existing traditional buildings. The study employed Fukien cypress and Cryptomeria japonica as the basic experimental material; they are two kinds of timber frequently used, and yet each with different properties. It is known that traditional stain layers come in rich colors; however, for the purpose of the tests in the study, four basic colors of red, yellow, blue and green were utilized. The aim was to test the effect of different factors on deterioration rate of the pre-selected timber, colors, paints, and tung oil. There were 160 samples in total. For the deterioration tests, there were five factors in question and they were indoor lighting, outdoor lighting, resilience to acidity, and ultraviolet rays, and constant temperature and humidity. After the deterioration tests, data regarding color differences and contact angles for water drops were collected to yield results. The study aimed to compare color fading levels and hydrophobic properties of cypress and cedar (painted with varied stain layers in different colors, e.g., read, yellow, blue and green) after a long period of deterioration tests. Results have shown that, in terms of ‘color effect’, red had the highest rate of color fading, followed by yellow, green and blue. As to ‘timber or paint effect’, results did not show any significance. In terms of ‘tung oil effect’, no significance was revealed, because tung oil was administered only to the basement materials coated. Of the five deterioration tests, outdoor lighting had the strongest effect on the rate of color fading, followed by ultraviolet rays, acid rain, constant temperature and humidity and indoor lighting. Regarding the contact angle results of water drops, the overall data did not show any weakening of the hydrophobic properties, because the timber was protected by five layers of paint. It is suggested that the time for the deterioration tests should be prolonged in order to try and generate results regarding differences of hydrophobic properties. It is expected that the results reported above regarding color fading and the weakening of hydrophobic properties can serve as a useful reference for future protection of stain layers of traditional buildings. It is also hoped that the results will benefit subsequent research related to staining.