Since the installations are similar as far as prep and cost, my decision lies on which is more forgiving to a little bit of floor bounce. The bounce is very slight. If you do the ‘bounce test’ you don’t notice it, but if the one of the kids runs through the room, you can hear things in the hutch rattling.

The hutch is right next to the doorway, so it is very close to the footfalls causing the rattles. Doing the ‘bounce test in the middle of the room produces no rattle from the hutch, so I assume the floor is fairly sound.

I have seen flexible mortars on the market. Will this work for me, or should I stick with vinyl?

The house is over 100 yrs old and working with the joists is not feasible due to odd ducting and plumbing runs by the previous owner.

Thanks in advance