Residential sound insulation between floors.
Very Old house wood framed. My question has to do with residential sound transmission between floors. I have access to the joist bays for the second floor floor and second floor ceiling. I do not want to remove the first floor ceiling and can not add another layer of sheet rock over existing first floor ceiling. I was told by an acoustical Engineer that it does not matter what insulation I use, be it fiberglass, cellulose or rockwool they will all provide roughly the same STC as long as the cavity is filled. He also said that if I install a product called regupol which is a type of rubber under the finished floor over the subfloor that will help reduce the impact sound. He explained that unless I can separate the connections between walls and floor/ceilings, the sound will still carry into the spaces you do not want it to go. So given that I’m try to do the next best thing. I would like your advice about the type of insulation I should add to my open joist bays for limiting sound transmission. I plan to insulate all the band joists with closed cell spray foam and all my walls are currently insulated with fiberglass.
Thank you, Kevin
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