Insulation between floors using trusses

[Leland S.]

I have a 3 floor townhome with trusses and a flat roof. I hired an insulation guy for flash/batt and noticed he didn't insulate between floors. When asked he and my GC said it's not required. I believe I am supposed to follow the 2018 IRC code, but it's so dang complicated you need a specialty engineer to understand it. Ultimately it will show up in my framing inspection, which I haven't heard back from yet, but my assumption would be that every space between interior drywall and exterior siding should have a layer of insulation.