Tips for a Quieter Ceiling
To quiet footsteps from the floor above, consider adding fiberglass batts to the joist spaces. You can add a 3-1/2-in. layer, or better yet, fill the joist spaces with fiberglass. For even more noise reduction, isolate the ceiling drywall from the joists with resilient channels. Screw the channels to the joists, spacing them 12 or 16 in. apart (ask your building inspector what's required). Then screw the drywall to the channels, being careful not to drive screws into the joists. This creates a “floating ceiling” that reduces sound transmission. You may have to visit a drywall supplier to find resilient channels.