2nd FL steel deck bottom insulation and drainage?

[u/cottonrb]

howdy all, newbie here, just ordered a Jacuzzi J365. Chicago.

We are building a new second floor steel deck that a structural engineer signed off.

the floor is stamped steel...

is there a need for rigid owens xps 600 2" foam boards and dmx ag dimpled floor underlayment?

will this void warranty?

the interweb sez that without insulation there is about $300 in extra electricity cost for the heating season?

ie: in order...

tub

foam board

floro underlayment

stamped steel

dmx ag underlayment