the invention was developed with a view toward providing an improved a interior joint structure for a building container or the like with reference to the figure two substrates 2 4 come together to define the joint section such as a corner or as shown an expansion joint in the illustrated embodiment the expansion joint is filled with an elastomeric sealant 6 the substrates are usually concrete often coated in the illustrated embodiment the concrete which carries a polymer coating 8 a chemically inert polyolefin tape 10 covers the joint section an adhesive material 12 according to the invention secures the chemically inert polyolefin tape to the substrates to provide a strong bond between the substrates and the chemically inert polyolefin tape the chemically inert polyolefin tape 10 is preferably highly resistant to strong acids and bases and is flexible and tear resistant so as to resist loss of fluid tight integrity in the event of relative movement between the two substrates which define the joint section a highly suitable tape for use in accordance with the invention is formed from chlorosulfonated polyethylene which has been cross linked and has a thickness in the range of from about 0 1 to about 10 millimeters a preferred tape is one which has been cross linked with an aminoalkoxysilane and has a thickness in the range of from about 0 3 to about 3 millimeters with a mid section of the tape having a greater thickness than edge sections of the tape an exemplary tape formed from this material is resistant to strong organic and inorganic acids e g glacial acetic acid 98 h 2 so 4 70 hno 3 and 85 h 3 po 4.