A common approach is to shoot (PAF’s) metal hat channels to the bottom side of the EPICORE MSR deck after the concrete has been poured and then screw drywall to the hat channels (Note that the drywall is not required to achieve the U.L. rating). In an apartment or condo project with a lot of overhead electrical, it is preferable to use 1.5” or 2” hat channels so that you can run the electrical underneath the EPICORE MSR and have enough plenum depth for the shielded cable, conduit, and electrical boxes.
You can also hang a metal ceiling grid on wire and screw the drywall to the metal grid. This gives you more plenum space for ducts, sprinkler pipe, etc. The STC and IIC rating can be slightly higher with a suspended drywall ceiling as well.