The problem is not the box but how it is mounted. Looking at HD, that box is only rated for a 35lb fan. You need something stronger. There are a couple of ways to do this, depending on whether your ceiling is open to the joists, or accessible from above, or not. If open, you can use a 2x4 nailed in between the joists. The box then will be attached to the underside, so leave enough clearance for the box and sheetrock. If closed, then there is a device out there that I've used several times. It is a steel rod-like thing that expands. The ends have spikes that, when expanded, drive into the joists to hold it. It screws together and fits up into the ceiling through the hole for the box. Once up there, you 'unscrew' it which lengthens it until it firmly grips the joists. You then attach a metal box to it with the hardware provided (U-clamp and aircraft nuts). Here is a link that might be useful: HD westinghouse fan box

Just bought a home in SW Florida - built in 1962. It has great bones, terrazzo flooring and original AC unit. Dilemma is this - There are AC circular type vents in the center of each of the bedrooms and other rooms as well. Is there any way to add a ceiling that would also work along with a vent? I love a ceiling fan, especially in the bedroom but without actually re-locating these vents......(expensive), there is no way to install. Help!!! Many thanks.

Here's the Boveda ceiling in our front foyer. Boveda ceilings are brick vaulted and were first introduced by the Moors to Spain when they conquered parts of it. And then the Spaniards introduced them to Mexico when they conquered it. You see them a lot in places like San Miguel de Allende in Mexico, which is where our foyer light fixture came from, as well. The bricks in our ceiling are over 100 years old and really interesting to look at close up. The tapestry is a copy of one from our McGregor Clan in Scotland. Scottish and Spanish, but they work together for me (LOL). This pic also shows how thick our adobe walls are. And yes, the photo isn't skewed, the opening there is arched.

The best solution is to stop it at the source. Carpets and talcum powder will solve 2 of your problems (talc will act as a lubricant between adjacent boards). If the floors squeak between the rafters and bottom of the floorboards, they have to be anchored better, with screws. You need insulation that has some mass. Lightweight insulation is fine for cutting down reflected sound, but to block transmission you need mass. There is sound-deadening sheetrock. But there is no easy solution to cut down transmission.