Hello,
I am currently renovating the lower unit of a 2-story 2-family house. The upper units is finished, and has hardwood floors on 3/4″ advantech T&G subfloor. I am looking to do whatever I can to minimize sound in the lower unit.
I have read the 2 articles I found on FHB, and checked out other websites regarding minimizing ceiling/floor sound transmission.
I am wondering what other opinions there are to minimize structural borne sound. If there is consensus on the best thing to try. Acoustic clips vs spring loaded clips or resillient channel. In “Quiet Please” Russell DuPree writes about mass loading with 2x 5/8 in joist cavities by fastening the drywall to the subfloor above. I read elsewhere that one could add GG here to improve the effect, but it doesnt make sense to me- as it seems that the effect is largely from adding mass, and that sound will be transmitted through the floor joist. Also, the GG peopel say you should add to walls as well as sound can flank, and be heard through walls.
Thank you
Replies
I guess you have put safe n' sound between the joists?
A little late as you have already finished the top units, but this is what I would have done starting from scratch.
Engineered hardwood floor glued to rubber underlay. Advantech glued and screwed. Existing floor joists cavities filled with mineral wood batts. Resilient channels with sound isolation clips. 5/8" drywall.
Without the underlayment, it is going to be difficult to isolate the structure born sound. Still, the floor system I'm suggesting even without the rubber will give you pretty good results.
5/8" rock screwed to the Advantek from below with Green Glue works more by constrained layer damping than by mass effect. It will keep the upper floor resonance down, which will help even at the joists.
A double drywall/GG ceiling on strapping with cellulose completely filling the joist cavities would complete a very quiet floor/ceiling. If flanking paths excite the walls, a second layer of DW with GG (on those walls)is the simplest effective way to reduce that sound, as there is no demolition involved.
The ceiling alone could be made quiet simply by adding Quietrock THX, but leaving the cavities open increases the odds of flanking noise getting around the lid.
Bill