Silyl-terminated polyether (STPE) was introduced in 1979–1980, and ever since, silyl-terminated polymers have become one of the most important technologies of the sealant and adhesive market. In the Japanese market, STPE sealant is well known in dynamic joint applications for high-rise buildings for its properties that promote high durability and maintain good performance over 15 years. Recently, a new polyacrylate incorporating STPE technology has been developed that has enhanced durability and weatherability. Silyl-terminated polyacrylate (STPA) was launched in 2008 to meet requirements such as enhanced durability and ultraviolet (UV) resistance for sealants in the construction market. This polymer has been used as a high-end construction sealant because it performs well for more than 30 years. However, with the extension of sealant life in the construction market, there has been an increase in the adoption of accelerated tests that can evaluate UV resistance and the durability of the sealant in the short term. Moreover, the requirement for lifetime prediction, i.e., to design sealants that can be guaranteed to be waterproof for several decades, is increasing. A large amount of data on accelerated weathering resistance tests has been reported to date. In this paper, we discuss the lifetime expectation for the waterproofing ability of a sealant from the correlation between various accelerated weathering resistance tests. We also analyzed the difference in deterioration progress for STPE- and STPA-based sealants. We found that the depth of cracks formed by various accelerated weathering resistance tests correlates with the irradiation energy. In addition, based on our studies, we assume that polyacrylate-based sealants will maintain their waterproofing performance for a longer term than STPE-based sealants because the deterioration speed within the sealant is comparatively slow.