Abstract: A covering for an expansion joint of a building is formed from an extruded thin vinyl strip having a relatively thick expanded plastic insulating strip secured to one side of the vinyl strip. A reinforcing strip of material may be bonded securely to the vinyl between the vinyl and foam insulating strip in a sandwiched configuration to provide dimensional stability for the assembly and particularly to resist shrinkage of the assembly in a longitudinal direction. The vinyl strip is wider than the foam insulating strip to define longitudinal marginal flanges extending along the length of the strip. Metal nailing strips are embedded in the longitudinal flanges to facilitate attachment of the flanges to the spaced building sections which define the expansion joint. The nailing strips are formed to define a weakened, longitudinally extending line to facilitate longitudinal bending of the flanges along the nailing strips directly at the construction site without the use of heavy bending equipment.