assists in the seal between the fire pack retainer 34 and the elevator shaft 10 thereby retaining a loose fill fireproof material in place improving the sound insulation of the elevator shaft 10 and providing an easily decorated surface in the building in which the elevator shaft 10 is installed fig3 shows three types of prefabricated elevator shaft modules a pit module 11 is located below a stack of shaft modules 12 and 13 and has a joint as described above on each upper corner thereof a prefabricated elevator motor room module 14 is secured at the top of the stack and includes all the motors and cables necessary for operation of the elevator a prefabricated elevator car 39 is also included in the fully assembled elevator shaft 10 and the shaft modules such as 12 and 13 have elevator doors 40 control panels 41 and the other apparatus necessary for operation of the elevator when assembled assembly of the elevator shaft involves the sequential building of a stack of elevator shaft modules according to the height of elevator shaft required the individual corner joints are assembled by lowering an upper shaft module 13 over a lower module 12 already secured in place to assist in locating adjacent modules a guide bar formed as a tapered guide pin 50 as shown in fig4 can be attached to the top of.