Author Topic: Building Floating Room - Need Advice  (Read 15277 times)


  • Guest
Building Floating Room - Need Advice
« on: March 26, 2007, 04:23:40 AM »
First of all - GREAT SITE! Lots of good advice.  Second of all - I'm building a studio and would love some input. 

I am moving to a new house and am planning on building a recording studio in the basement.  I've been recording for some time and built a studio in the house where I live now (I've included a couple of pics - though it's hard to see). In my current studio, I pretty much gutted the basement and rebuilt the ceiling and the double-wall between the studio and the control room and added a 1/2 inch plexiglass window. It works pretty good although at my next place I really want to soundPROOF the basement - as now I have a 7 month old daughter who enjoys going to bed early and I don't want to piss off my new neighbors. 

I was thinking that there would be 2 rooms again.  The studio would be approx 12ft X 14ft and the control room would be about 12ft X 8ft with 7 foot ceilings in both rooms.  This is how I was thinking of doing it.
  • Framing the rooms with 2x4s
  • Leaving about a 6 inch gap between 3 walls and the ceiling
  • Leaving about 3 feet between 1 wall (as a corridor)
  • There would be 2 doors (1 to the studio and 1 to the control room)
  • I will probably just hang blankets on the original wall to deaden the area within the sound gap
  • The walls will have 1 layer of 1/2in soundboard, followed by 1/8 in vinyl roll, followed by 5/8 in drywall, with 2 inch foam on all walls and the celing
  • There will be a 1/2 in (approx 5 ft X 3 ft) plexiglass window between the 2 rooms (do you think 1 window is enough?) - right now I have 2 - but was thinking of just using 1
  • The room will be built on rubber bumpers and will not touch the walls anywhere
  • The wall between the 2 rooms will be framed double with the walls both having the coverings on them - they will only be a couple of inches apart and will not touch - although the window will tie the walls together
  • Not sure how to address the 2 heating/ac vents - advice please

Any advice is very much appreciated.  I am shooting for a STC rating of about 64.  Do you think I can get it? I do not want the drums/bass to be heard upstairs or outside and we play LOUD!

Thank You!!!!!


  • Guest
Re: Building Floating Room - Need Advice
« Reply #1 on: April 02, 2007, 05:35:12 PM »
hello dirizen,
1/8" MLV (Mass loaded vinyl) works best when applied directly to wall studs and ceiling joists in a continuous layer.  When you pin it flat between sheets of drywall its sound blocking effectiveness is reduced - it needs to be able to flex (like a diaphram) to be fully effective.  I would staple the MLV directly to studs, apply isolation tape (1/8" thick closed cell foam gasket material) right on top af the MLV where studs/joists are beneath - this will decouple wall/ceiling panels from structural's so that vibration does not get into structure.  Then apply your two layers of drywall with Green Glue sandwiched between - Green Glue sandwich lowers the resonant frequency of the assembly, thereby blocking bass frequency sound better.   You may also want to consider absorbing and blocking sound within the wall/ceiling cavities by using bonded cotton insulation - this costs around twice what fiberglass insulation costs and gives 5x better sound absorbing and blocking.


  • Guest
Re: Building Floating Room - Need Advice
« Reply #2 on: April 02, 2007, 06:56:24 PM »
Thanks for the rep Joel: Couple things,

  • Would you use 2 layers of drywall or 1 layer of soundboard and 1 layer of drywall?
  • How do you handle the heating/ac ducts?
  • Do you think carpet is a good idea?
  • What percentage of the wall/celing space should be covered with acoustical foam?


  • Guest
Re: Building Floating Room - Need Advice
« Reply #3 on: April 02, 2007, 07:36:59 PM »
Sorry, one more thing.

In the picture on your site

It shows the Vinyl sandwiched between the soundboard and the drywall but in your reply you said to staple it directly to the framing.  Just wondering if you could clarify that for me.



  • Guest
Re: Building Floating Room - Need Advice
« Reply #4 on: April 04, 2007, 04:16:13 AM »
Sorry, one more thing.

In the picture on your site

It shows the Vinyl sandwiched between the soundboard and the drywall but in your reply you said to staple it directly to the framing.  Just wondering if you could clarify that for me.


Sure.  If you have framing, staple to it.  If you add soundboard, staple to it.

BJ Nash - Senior Soundproofing Technical Specialist
Super Soundproofing Co


  • Guest
Re: Building Floating Room - Need Advice
« Reply #5 on: April 13, 2007, 06:26:18 PM »
Hello all!

I have been studying and reading and learning for a couple years (on this site and others) about how to build a soundproof (I actually prefer the term "sound reduction" now) room in my basement.

My band plays LOUD.  Like jet airplane loud (120 dB+ at times).  Yes we wear earplugs. :)

So I finally went ahead and did it.  I built the room. 

Your mileage may vary - so take this only as one anecdote of supporting info: the advice on building and materials you are reading in this chain basically worked for me.

The sound of the kick drum and bass is now only BARELY audible if you stand very still near the basement wall and listen for it.  From standing at the neighboring houses (which are pretty close - like maybe 12 feet away) you cannot hear it.  Basically - I cannot measure the difference between normal city sound outside my house and my band playing.  This is a very good thing.  Not perfect - but very very good.
I will try to give more details about what I learned in this process and what a "normal guy" building a room runs up against - but I must say - I followed this design and it works for me.

1. Built a separate "floating" slab that does not touch the basement floor or foundation
2. insulated the ceiling of that area of the basement with the bonded cotton insulation
3. covered the cotton insulation and ceiling of that area of the basement with 1 lb MLV (attached to the floor joists above with a cap nailer - works great!)
4. built a free-standing room on the slab with its own walls and separate ceiling (does not touch the basement ceiling above!)
5. covered and sealed that free-standing room in 2 lb MLV (cap nailer again!)
6. put the closed cell 1/8" tape (2 layers) on every other stud (on top of the MLV) - to give a little air gap for the MLV to stay limp
7. 1 layer 1/2" drywall (horizontal)
8. layer of green glue
9. 1 layer 1/2" drywall (vertical)

I took measurements of drum kit and guitar playing at every new layer of mass, and have the numbers if folks are curious.  Real world SPL numbers for each layer.  Also I have the actual subjective experience of hearing what each layer did and will try to share it here eventually if folks are curious.  I also took pictures along the way.

At first I was really surprised how little the last (and most expensive!) layer of drywall + Green Glue was seeming to do.  I really expected a big jump in the sound reduction (especially the bass) with that extra mass and the high tech glue layer - but I wasn't seeing it on the meter - and while I could hear a difference - it wasn't as monumental as I'd hoped.

But after about 3 weeks suddenly the Green Glue must have "set" or something (the packaging does say wait 30 days - but at the prices Green Glue costs you really want those immediate results!).  The difference was pretty amazing if you ask me.  Suddenly the kick drum and the bass were tamed! Awesome!

My take - don't give up on the Green Glue - give it time to set and it seems to really (and I mean really) work!  It was like night and day for the bass frequencies in my case.

I'll post more about my experiences if people are curious - but my simple advice is that the ideas listed here seem to work, and that the devil is truly in the details with sound reduction.  Seal every crack, tape every seam, and don't skimp on materials (but apply your funds judiciously in the right places - MLV, Drywall, Iso Tape and Green Glue).   

Mass-Air-Mass, variation in materials, and keeping pieces "disconnected" from each other all helped for my room. 

Just a general info post and a thank you to all the advice I read here and everywhere in the sound reduction community!



  • Guest
Re: Building Floating Room - Need Advice
« Reply #6 on: April 16, 2007, 01:49:35 AM »

Glad you got good results.  In the interest of full disclosure, what was the size of the room and total cost of the project? 


  • Guest
Re: Building Floating Room - Need Advice
« Reply #7 on: April 26, 2007, 04:39:51 AM »
Good point - cost is always something to consider!

So the room is basically 16 x 8 - which is a nice size for what i needed, but in retrospect feels a little small with more than a couple people in there once we got the drum kit all set up.  Totally workable and tolerable for a 3 piece rock outfit used to cramped practice spaces - but not spacious by any stretch.  Any guest players will be sitting in my lap. ;)

Total cost of the project - I am approximating here based on running through my receipts - around $5,000 at the low end - maybe 6 at the high? GULP!  I hadn't really done the math because expenditure was spread out over the months of work to get it built and trying to quickly forget the wallet pain by playing loud in my own space! 

Most of that is raw materials - but I bought some tools like a Hitachi Cap Nailer (~$400!) that I'll probably never use again now - but was kind of a life-saver with that heavy MLV flopping on my head.  Also lots of helping hands from friends can save on costs.  Near the end - I was just trying to power through so probably spent more on drywall and materials at the Home Depot than if I had planned a little better for that last mile.
And keep in mind - I still haven't solved the HVAC but I am kind of strapped after that initial run - but I am thinking a split A/C unit which doesn't look too bad - but need to do more research.

We've played in there a few times and never felt like we didn't have enough air for a practice - but still its coming into summertime and it will get hotter!

I hope this helps give some approximate for costs - it ain't cheap to reduce sound and plan a decent budget for materials!  I definitely ran over near the end.