About us


Mar. 1953 Inaugurated as Showa Kako Co., Ltd., a subsidiary of Showa Sekiyu Co.,Ltd. (At present: Showa Shell Sekiyu K.K.).
Apr. 1955 Manufactured and marketed void filling materials and oil caulking materials.
Sept. 1960 Built the Tokyo plant in Ariake-cho, Fukagawa, Koto-ku, Tokyo, aiming for manufacturing asphalt and concrete.
Sept. 1968 Merged with Niigata Asphalt Kogyo Co., Ltd and changed the corporate name to Showa Sekiyu Asphalt Co., Ltd. Started manufacturing and marketing of asphalt waterproof materials.
Sept. 1968 Relocated the Tokyo plant and established the Sunamachi plant.
Apr. 1969 Relocated the headquarters to Minami Oi, Shinagawa-ku, and established the research laboratory and the Tokyo plant on the same premise. Started production of architectural sealing materials and coating film waterproof materials.
Jan. 1973 Started marketing of the TOUGHNESS Sheet.
Jan. 1985 Changed the corporate name to Shoseki Kako Co.,Ltd. .
Dec. 1985Relocated the headquarters and the Tokyo sales office to 1-11-2 Yoyogi, Shibuya-ku, Tokyo.
Oct. 1987Totally renewed the asphalt mixture plant of the Sunamachi plant in Tokyo.
June 1989 Started marketing of the Highness sheet.
Oct. 1989Constructed the Yokkaichi plant.
Apr. 1992 Yokkaichi plant acquired JIS mark indication approval (JIS A 6022).Started marketing of the RAPINESS Sheet.
Nov. 1992 Completed the recycling plant at the Sunamachi plant.
Sept. 1995 Registered the patent of PaveDrain.
Apr. 2000 Started marketing of FL Coat.
May 2001 Acquired the ISO certification (9001) JIC Quality Assurance Ltd. JIC Q A0965
Sept. 2006 Started Highness sheet SW-S.
Jan. 2008 Started marketing of the SBS-based Milia Series.
Mar. 2010 Relocated the headquarters and the Tokyo sales office to 2-3-2 Daiba, Minato-ku, Tokyo.
Nov. 2014Started marketing of X-Armor.
Oct. 2016Started marketing of Toughness fine.