Sealanｔｓ are subject to fatigue failure due to random stretching. In order to predict the service life using the cumulative damage theory,it is necessary to determine the statistical characteristics of the degree of cumulative damage,and then to decide on the value. To investigate the degree of cumulative damage,a fatigue test was first carried out to obtain the life curve, and this was then used to perform a multi-stage fatigue test. From this investigation it was found that a value of the degree of cumulative of around 0.8 was applicable. The cumulative damage theory was used to investigate the prediction of the service life of he sealant in a working joint. As a result, the life of polysulfide was found to be from several years to several tens of years.

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External finishings of building plays prominent important role to ensure the service life of the building. This paper firstly discusses the method of service life design for external finishings, on the basis of performance oriented concept and then points out the necessity of performance‐based data on performance over time of external finishings, not merely the data on the empirical durability characteristics, that could be obtainable by performance evaluation methods likely outdoor exposure tests, laboratory tests, pathological condition survey on site and even inclusive of expert knowledge, In line with above investigation this paper shows several performance data obtained from long period outdoor exposure test results pertaining to external masonry coating system and protective paint coating system, and finally the usability of these data as a tool for predicting the service life of external finishing and applicability to the proposed service life design system are introduced.

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