Sound Break Between Exposed Beam Joists
Ceiling/Floor assembly for sound break between exposed joists
25’x32′, two stories: first floor 10′ ceilings; second floor vaulted ceiling 5′ knee walls to 12′ peak
The first 18′ (of 32′) of the first floor has exposed beam joists. There’s a wall at 18′ and the rooms on the other side of the wall have 2×10 joists that will be covered. Stairs are located in that covered joist section of the building.
In researching ways to minimize sound travel between floors seems like best practices include: combining different types of materials; air space filled with some mass; breaks between like-materials.
The stairs are framed already for a floor that doesn’t include an added assembly (subfloor is 1″ rough cut pine boards, 1/8″ Steico wood fiber panels for underlay, 3/4″ pine boards for finished floor).
I will beef up the sound insulation of the ceilings in the back 12′ of the first floor, but can’t do the same for the exposed beam section.
Goal: Minimize airborne sound travel so that at the very least the content of speech cannot be discerned between floors, at this point on a very tight budget.
Here are what I see my three options are:
1. Keep the whole floor assembly the same and minimize the exposed beam section by adding 1″ wood furring on each side of joists, 1″ cotton batts, boards onto the furring.
2. Floor assembly the same above covered joist rooms (because I can do the sound work on ceiling below and to keep the stair rise equal on that last one), with a offset threshold onto a floor assembly above the exposed joists that’s something like: sleepers on top of glue or thin underlayment, 1″ cotton batt between, plywood on top of sleepers, Steico underlay, finished floor.
3. A combination of both. Seems like this one is obviously the most effective but would the added cost/time/labor be worth it?
Thanks for input, and of course just like thermal insulation, these interventions won’t be much effective if I’m not also taking care to seal it all up.
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Well, there was a lot of information in there, but let me take a swing at what I would do to soundproof. Generally if underfloor assembly is not going to be modified I would go with a cork floor underlayment and air sealing. If I was going to design one for a gut remodel I would either create an uncoupled ceiling with new joist or use resilient channel to hang two layers of gyp with green glue and again air sealing, perhaps with intello, and dense packing or rockwool in the joist space.
as you said if you are trying to negate airborne noise the biggest factor is air...
if trying to deal with footsteps then I think decoupling the ceiling is the most important. '
If doing this:
"1. Keep the whole floor assembly the same and minimize the exposed beam section by adding 1″ wood furring on each side of joists, 1″ cotton batts, boards onto the furring.
I would try to add a layer or two of gyp behind your boards and maybe use an acoustic caulk to seal to beams and then add your boards. also instead of furring, using a resilient channel or a purpose built isolating attachment might make more sense.