Replies

1. 
   Guest_ | Feb 16, 2000 07:35pm | #1

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   What type of flooring are you adding? tile in bath? hardwood? carpet?

1. 
   Guest_ | Feb 16, 2000 09:23pm | #2

   *The thicker the better. I'd use 1 and 1/8" T&G plywood. Between the joists I'd use R-30 insulation (not particularly effective for sound, but heck its cheap) and some 1/2" masonite soundboard.

2. 
   ggzz | Feb 16, 2000 11:36pm | #3

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   I'm an architect and ex-contractor and must say it is hard to find definitive answers to sound questions. I've hired sound engineer consultants and even had THEM disagree about designs. Anyway, you typically do it by: adding resiliency to an assembly (with flexible Z-channels; soundboard; double-floor or wall construction); increasing the assembly thickness and deadening the air space (adding wood strapping, then Z-channels or adding new joists or studs, all with sound (not thermal) batt insulation); or by increasing the mass. I assume you only want to build upward from your existing floor and I'd recommend beefing-up the mass by adding a few layers of sheetrock and/or particleboard. The washer/dryer I put in an apartment recently sits on 5/8" exterior drywall sheathing (it's water resistant and extra dense) then two layers of 3/4" particleboard I had lying around. It's a very dense assembly and all I could do without opening up the floor and it works quite well. I personally don't believe that soundboard would buy you much in this kind of assembly.

   Can you build up the ceiling below it? This would change things.

   GGZZ

3. 
   Guest_ | Feb 17, 2000 03:41am | #4

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   .......sound transmission is tricky (as already stated above)... especially watch all penetrations first..

   ..next , given that the beams and the bottom of the 2x10 's are going to stay as they are (?????) right ?

   .....Benjamin Obdykes resilient mesh (also sold as shingle breather) is 3/8"

   Then Homasote sound board 1/2"

   and either 3/4" t&g ply or two layers of 1/2" crossed, then your finish floor, oak tile, carpet...

   I like the drywall.. it has good inertia and desity... but I would only want to use it in a sandwich...

   You might also look into pouring one of the layers with gypcrete.....

1. 
   Guest_ | Feb 17, 2000 09:21am | #5

   *Homasote is the easy solution, and the one I'm using in our upstairs addition. It is sound-deadening, not too heavy and, installed staggered, will help cover cracks in the subfloor. About $17 4x8x1/2". See http://www.homasote.comSealing holes, filling joist spaces, resilient channels are all additional or alternative strategies. I'm using most of them (small and active boys!). Holes & HVAC ducts are a big deal.Don't worry so much about Homasote and moisture, despite appearances it's not like particleboard. I left a stack of 20 outside for a month in rain/snow and some water got through the tarping. Even the very wettest of the panels is still fine ... a little curvy, but I stuck it at the bottom of the new stack to flatten it.

4. 
   ggzz | Feb 18, 2000 01:19am | #6

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   Hey,

   I liked your comments. I forgot to mention sealing all penetrations, joints and cracks. Would like to try xome resilient mesh. Is it available easily? Gypcrete could break up over time. I still prefer mass to sound board on a floor situation but you proably need a good inch of gyp board & cover with ply.

   Anyway, whaddya all think of sound proofing a lath & plaster ceiling? I would typically spray cellulose up into the floor cavity, then add resilient channels and another ceiling of 1/2" GWB. However, the hardwood floors and 1-by subfloor go in the same direction so much that ANY spilled liquid goes right through it onto the ceiling below. This would kill the cellulose. Therefore, I'm thinking of doing a sheet of poly, wood strapping (3/4", then resilient channels, maybe some thin fiberglass batts if I could find them, then a 1/2" gwb ceiling.
   WHAD D'YALL THINK?

1. 
   ggzz | Feb 18, 2000 01:19am | #7

   *Hey,I liked your comments. I forgot to mention sealing all penetrations, joints and cracks. Would like to try xome resilient mesh. Is it available easily? Gypcrete could break up over time. I still prefer mass to sound board on a floor situation but you proably need a good inch of gyp board & cover with ply.Anyway, whaddya all think of sound proofing a lath & plaster ceiling? I would typically spray cellulose up into the floor cavity, then add resilient channels and another ceiling of 1/2" GWB. However, the hardwood floors and 1-by subfloor go in the same direction so much that ANY spilled liquid goes right through it onto the ceiling below. This would kill the cellulose. Therefore, I'm thinking of doing a sheet of poly, wood strapping (3/4", then resilient channels, maybe some thin fiberglass batts if I could find them, then a 1/2" gwb ceiling.WHAD D'YALL THINK?

5. 
   curtf | Feb 18, 2000 01:19am | #8

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   The second floor of my house is tongue-and-groove 2x10 on top of large beams. I want put a new floor on top of this in the master bedroom/bath, and I want to reduce the sound transmission from below into this room. What type of subflooring could be used for this? The soundboard typically used on walls seems like it would be too much of a sponge to be used under a floor, should spills and moisture get to it. Naturally want to keep the built up thickness to a minimum.