onto the reinforcing mesh fabric elements which once inside the locking portion cannot escape triangular shaped mold spacer portions 30 and 32 are provided that extend beyond both of the locking portions to space both sides of a double fabric assembly from corresponding mold walls fig1 d and 1e show at 40 an embodiment similar to that shown in fig1 a 1c with the exception that only a single mold spacer portion 32 is provided such a spacer may be useful in assembling a reinforcing structure in an application such as a sanitary sewer or the like in which leakage through the structure in the vicinity of the spacers cannot be tolerated alternate exemplary embodiments are illustrated in fig2 a 2c in fig2 a there is shown an alternate embodiment 50 in which a first locking portion 52 has an entrance facing away from and generally parallel to the central portion 54 such that a spacer 50 can simply be inserted through an opening in the mesh of a first fabric and the locking portion 52 snapped directly onto an element of the spaced second fabric and then the second locking portion shown at 56 simply snapped onto a corresponding element of the first fabric without the need to maneuver or manipulate the spacer device further that embodiment is shown with one mold spacer.