I need soundproofing advice, I have an upper lower duplex and live in the lower unit myself. The sound from the tenants above is obnoxious, I can hear everything. My home was built in 1957 and there are hardwood floors under all existing flooring (carpet and linoleum). The floorboards also squeak and it doesn't seem to be confined to certain areas.  What are my options for decreasing the sound transfer, and reducing squeaky floors?

@Albert Olivarria , there are various options for helping with squeaky floors, depending on the situation. Some may be fixed with a well placed screw, but in other cases there isn't much you can do without pulling up parts of the hardwood floors.

The best fix is, unfortunately, a pretty big job. You pull down the ceilings in your unit, fill all the joist bays with mineral wool insulation, seal all floor penetrations with sound-proofing foam, and finally hang new drywall using resilient channel. Do that and you won't even know you have tenants until the rent check arrives.

Thank you Jaysen, appreciate the information.

@Jaysen Medhurst @Albert Olivarria

I have been contemplating the best and cheapest way to soundproofing my 3 floor apt building.

I do not want to demo the existing ceiling because it is very heavy plaster.

I believe the best solution without demolition is to:

1) add 2" metal channels to existing ceiling. You can add RC clips for better results.

2) add 2" pink insulation between the metal strips

3) add a new 1/2" drywall ceiling. Add 2 or 3 drywall layers for best results.

Read this test (look at test #5)

http://www.mjm.qc.ca/publications/en/177881_Floor-CeilingAssemblies.pdf

The most critical mistake that people make is not leaving a 1/8" gap between the new ceiling and the wall.  The new drywall ceiling should not touch the wall to prevent sound transfer.

Thanks for this, @John Kim . That's a good technique, especially if you can give up a few inches of ceiling height.

How how did your son proofing go? Are you satisfied with your results?

We have torn down the ceiling in our basement apartment, and are prepared to fill the cavities with roxul safe and sound insulation, install metal resilient channels, topped with 5/8 drywall. I will also be looking for holes in the ceiling to add acoustical caulk. I'm hoping this is enough, but I've been reading about isolation clips, also referred to as whisper clips or channel clips to hang the resilient channeling from. They are pricey, at five bucks a piece. does anyone know if they are worthwhile or not? Also, if we do one layer of drywall currently and find out later we want to add more, is it okay to have another layer added with green glue to the previously finished and textured layer? We are okay with spending some money on this project, but would like to keep it under control.

And for your humor, you should know that we found four if not five sheets of chip wood/mdf screwed to the ceiling in our basement! They then proceeded to finish the rest of the basement ceiling with drywall. You can imagine our shock finding out half of this room is covered with wood! Still scratching our heads trying to think of a decent way to get it down. Best solution we've come up with is to set the skill saw to the wood depth and start cutting between the joists. 

@Laura Johnson , considering the other measures you're taking, I would skip the iso clips and do a 2nd layer of drywall with the green stuff between.

@Laura Jonhson, I realized my issue was more in the master bedroom of my home, and after further research I found that three of the four walls in Master bedroom have heating ducts running up to the upstairs unit. This is most likely the cause of the easy transfer of noise from upper to lower units. 

I dont think there is a good way of fixing this without extensive work and money, but I am open to any suggestions.