slab or floating floor?

Hi, i have the following design idea from John Sayers. http://www.johnlsayers.com/phpBB2/viewt ... uter+noise right now it is a concrete slab and the concrete comes up about a foot on all sides except the side with the garage door (north wall). do i need to float the floors for each room? for isolation between rooms? or will the concrete surroundings and the double leaf wall be ok? if i do need to float a floor, which room woud benefit from a floating floor more... the control room or tracking room? the garage is attached to the house and i have neighbors 100 feet away. Thanks!

floating the floors is a question of expense, you certainly will get better isolation by floating the floors, mainly between rooms inside the building, but of course it is more work and expense. If I had to choose one room to float it would be probably the tracking room, but you could always just float the drums within the room. I can tell you though that even without floating floors - if you build the walls correctly there isn't any chance that your neighbors will hear anything 100 feet away - they wouldn't hear anything even if they were 20 feet away stood on their porch.

thanks for the reply. about dem walls... on top of the concrete there are studs for the outside wall, then some wood and then aluminum siding (yes im in jersey). i'm planning to: -stagger studs -fill w. fiberglass batte insulation (is this the same as rockwool?) -apply drywall on inside -caulk according to the stc chart, this would give me a 48, when i previously had a 28. would that be enough? thanks!

With the outside wall - this will not be very much mass - you might want to put drywall between the studs up against the wood and caulk it well. Do you plan on building a 2nd wall with an airgap between it and the existing outside wall?

not unless i absolutely have to... the air gap would come between the staggered studs which would be filled w. insulation. also, i will be constructing the sayers panel traps which will contain wood and insulation. i doubt i'll need more than that for the control room, but for the drum room i may want to add another layer of drywall on the west wall. do you agree? some math: i measured the drums, average sound with them being whacked is 95 spl. on all corners of my property (with garage door closed, no insulation) it is 61-65. then my neighbors houses are 20 feet or more away from this. on an average day with no music being played, the street noise is 50-55. would i be fine (isolation-wise from my neighbors) if, on top of the concrete slab and given all the absorption in the rooms, i built the staggered studs with just insulation and a layer of drywall? how about if i built a drum riser? i know it would help but enough to the point of making that big of a difference? i'm trying to look at a mathematical/scientific solution and solve with numbers as there is less guesswork involved. thanks again!!

Strangely enough, absorption in rooms does almost NOTHING for isolation; in some cases, the end result is MORE sound leakage, because we tend to "turn it up" more when it sounds good :cry: As to float/no float, I agree with Andrew on this - your neighbors probably won't care one way or the other unless you really get carried away - ideally, you'll be usually mixing at around 80-85 dB, which normal house walls and your 100 foot distance would render pretty inoffensive. However, when recording drums you may hit as much as 110 dB, which WILL carry; especially the lower freqs from kick drums and even low toms. For this reason, and assuming you don't have a problem with outside noise getting in, it makes the most sense to float the room where the drums will be. Besides improving inside to outside isolation, this will also come a lot closer to letting you set mics by listening to your speakers instead of trying to do it with headphones. Keep in mind, too, that if you only float one room you'll have a "step" to deal with somewhere - and floating both the CR and the tracking area will definitely let you get away from using headphones (other than for the talent, of course) Hope that helped... Steve

LOL thanks knightfly! i've been reading a lot of your posts and they're very helpful. you da man 8) ok, i plan to float the drum floor for in-out isolation and better absorption. there will be a step between the 2 sliding glass doors, but i'll deal with it (this will only be less than a foot high when done correctly w. neoprene, 2x6, osb, roof roll, osb (all filled w. insulation), right?). as for that double leaf wall, should the leaf on the drum side be: A) built on top of floated floor or B) directly onto the slab and the floor would go inside, decoupled from the wall by a flexible strip along the base? thanks!

I'm a bit lost on what you plan to do with the walls. When you say you are going to stagger the studs - which studs? I'm assuming the external wall is already in place. Are you going to stagger some studs out from this wall? Is the wall sill 2x6 or 2x4? Unless you have a mass-air space-mass then you are going to be totally disssapointed with the sound isolation. Your drums played loud will eventually result in the cops being called by one of your neighbors. Unless the walls are good then floating the floor is a moot point. Floating the floor will help stop low end transmitting through the structure, but it won't do much to stop the sound reaching your neigbours. You can always float the drums, but I'd put the main focus not on floating the floors but on the integrity of the walls.

the external walls (west and south sides) are on 2x6 sills. the 2x6 sills are on top of the foundation concrete (that comes out into the room an extra 2 inches or so.) regarding these 2 walls, i plan to stagger 2x4 studs onto the existing 2x6 sills and add insulation inbetween, giving mass-air-mass. the insulation here is the question... what to use? as for the double leaf wall separating the tracking room and the control room, do i: -frame the wall sills directly onto the slab -use neoprene to decouple the wall sills from the slab -frame the wall sill on the tracking side to the floating floor? thanks!

You can fill the gap with the fluffly insulation you can buy at home depot. Remember to stop sound you need mass-air-mass. You can get a decent mass on the inside with internal drywall - but the weak spot is the mass of the external wall facing. I doubt you'll end up getting the 48db reduction you expect. I think also you will find the step between rooms a royal buzz kill. If it was me - I would skip floating any floors, put the drums on a floated heavy riser and instead of doing the staggered studs I would add a 2nd internal wall while also trying to increase the mass of the outer wall by putting drywall between the studs. You'll end up with a well isolated building that you will enjoy being in and can play music in late at night. I don't think you are going to get that with the current wall design.

thank you for your reply. I'm still weighing the floated floor vs. the drum riser arguement. seems the riser would be cost effective and have a similar effect on absorption - which would help out with reflections - and structure borne noise (right?) the dilemma with the wall... there is still 2" of concrete lip that cuts into the room. are you suggesting insulation and drywall on the exterior walls and then another wall inside of that, sitting on the slab? if i had to build that second wall inside of the concrete then I think the room would be way too clausterphobic. definite buzz kill there, but so are cops. what if i put drywall directly onto the exterior osb to beef it up as you had suggested earlier. then caulk the crap out of it. would i have to do this to the ceiling as well? the ceiling is the roof of the house. the peak runs horizontal - it cuts the entire space in half east-west. there's nothing up there, just like the walls. -should i insulate, drywall and caulk that too so it's airtight? -if it's airtight, how would the roof breathe? thanks so much, fuzzy details are becoming clearer!

I would build your wall out flush with the concrete as you said, or for a few db better isolation you could recess the new studs by 1/2" and put RC on them, being sure to caulk VERY thoroughly at the seam between concrete and new inner wall - 6" of concrete by itself has an STC rating of between 55 and 58 dB, your walls won't need to be better than that. What about the garage door, have you any plans regarding that? The roof is another matter entirely - if you could post a sketch showing what is already there, and its dimensions, we can get started on it. Include every detail you can think of, including your average outside temperature and extremes, materials, thicknesses, spacing, everything - this HAS to be right, or as you said you'll have moisture problems. Include whether your roof frame is trussed, beam, collar tied, etc - The only reason things aren't looking as fuzzy to you is that you may not have realized yet just how many questions/answers there are still to go... :? Steve

LOL thanks! walls will go on top of the concrete. caulked to suffocation. i'll have to look into the RC. do you have a link regarding supplier/price in New Jersey? for the ceiling, i will get pics for you shortly. that will best explain. Garage door (north wall): the door opening is 10 feet in the center of the wall. I can't take the door out. It must look like a garage from the outside. on both sides of the opening we have the concrete lip again. I was thinking about putting rigid insulation on the door then building an insulated wall in front of it (on the inside) then putting in the panel trap. another thought would be to do 2 walls, one layer inside out, but there is an electrical panel on the west side that i need to leave 3 feet of space for. of course, 3 feet out from the panel cuts into the garage door. again, i'll try to post pics shortly. thanks again and have a great day, guys! :lol:

here's john's idea modified slightly.

heres the north wall w. garage door. i put some preliminary masking on the floor to get a feel for the general layout.

here's a shot of the wall stud sill. notice the extra concrete lip. i was planning to use the existing sill for new staggered studs. then insulate between and caulk. after further advice, i may beef up the outer wall with an extra layer of drywall or cement backer board. but there are tons of nails coming through from the other side.

here's a shot of the south side of the west wall. the header is what the inside of the house uses for the ceiling. but since the garage is right on the slab, the header is about 13' up there. as you can see, the roof and garage walls have wooden studs. the roof peak is about 4' from where the header meets the wall. there's also a window and a small attic vent.

heres a shot of the south wall, with window. this is where the back wall of the control room will be. see how the concrete comes up all the way around. i think this should be used to my advantage. the house floor is on top of the concrete, so there will have to be steps up into the house from the studio. see the existing door and steps in the east wall corner. these will have to be taken out. and a new door to the house will have to be inserted about 4 feet out from the corner.

the east wall, adjacent to the house. there is an attic access door way up there. i have a temperature controlled attic fan but i keep that door open for extra ventilation. i have put in attic stairs in my hallway so i don't need that for access anymore. there is dry wall here and inside the house, but i don't believe this cavity is filled with insulation. do i have to rip down the drywall? is there another way to fix this resonance problem?

here's the east wall detail. there is slab, concrete, some sort of sill, floor joists (uninsulated), drywall. unlike the west and south walls there is no lip. the wall is flush with the concrete, and there is no insulation on the other side of the drywall. the uninsulated wall resonates and acts as a drum. i'm weighing some options here: 1. tear down existing drywall, and treat like other walls w. staggered studs n insulation. 2. leave wall but glue insulation to it and let the wall act as a panel absorber. 3. build new wall inside of concrete lip. but wouldn't this create a 3 leaf issue? sorry for all the pics, but i'll stop now! thanks for all your kind advice.

sorry, one more thing. the weather. i'm on the New Jersey shore. unpredictable day to day, but all seasons are quintessential. rains a lot in spring and in the summer it can be 95 and humid as hell, but then we can get droughts too. autumn is amazing. somewhat dry and very pleasant. we get snow (sometimes lots of it) and freezing temps in the winter, which seemingly lasts forever. :x i'll need to protect my roof and keep it ventilated through the seasons. you guys and this forum are awesome and i want to make a donation but i loathe paypal. any other way to do it? thanks!

Jeff, haven't forgotten you just buried in projects - this is going to take more than a "breather" from projects to answer so I'll try to get started on it tonight. Pay pal alternative: :twisted: just send us your firstborn, prepaid, with a years supply of food - must be between the age of 14-30, sound of body, willing to work and take orders, experienced in building trades, engineering degree a plus... :twisted: All seriousness aside, I don't think John has any other methods in place, sorry... Steve

no sweat mate. the first born it is. :twisted: i really do hate paypal that much.

i guess that's picture overload :? i made a donation, but got an email saying it's still unclaimed... maybe i should start another thread taking things one step @ a time? that way there's not so much to bite off at once? thanks again jeff

Jeff, it's not that - I'm still in overload over my wife's accident and all the attendant BS, with no slack-time at work either - It's gonna take me a few days yet to get back to my normal level of "behind"... Steve