I’m reposting after my original post disappeared when the site went down a few weeks ago, so if this looks at all familiar please forgive me...
I’m ready to embark on my first project, and it definitely promises to be challenging, so I’m really looking for any advice, input, criticism, etc. which you can offer.
I run a small music store, and we have decided to build a couple of rehearsal studios there. The store is located in a 75+ year old, free-standing, wood frame building. The original plan was to convert the second floor, which is currently an apartment, into the studios. Unfortunately, the cost and requirements of meeting the local building codes (very strict) forced us to rule this option out.
The building does have a basement, but the ceiling height there is only 6 ½’, so that ruled that option out.
There were no building code obstacles to construction on the first floor, so we’ve boldly decided to compact our already small showroom area even more and construct the rehearsal studios there. I’ve attached a PDF file showing the basic layout we’ve decided on.
With a retail space immediately adjacent to the studios, the probability of both rooms being used simultaneously, and an income producing apartment upstairs, isolation, transmission loss, and minimizing flanking sound are (obviously) of the utmost importance to me! I’ve only the budget to do this construction once, so I want to get it right.
I’m planning on using double wall, double leaf construction with a floating floor (room within a room). I’ve got plenty of questions regarding specifics.
I’m planning on constructing the floating floor using 2 x 4's on EPDM pads, random stringers, Roxul. For the floor I was thinking of 3/4" plywood or MDF/ 5/8" sheetrock/ 7/16" OSB. Any better suggestions or improvements? An engineer at Auralex, with whom I consulted with a few months ago, suggested building the floor using 12" OC spacing instead of 16" OC spacing and using a wider spacing between the EPDM pads (i.e. 32" for 12" OC instead of 16" for 16" OC) except around the edges, where the walls are being supported, using no more than a 12" spacing between pads there – he claimed that their testing seemed to indicate that this arrangement resulted in better isolation. What do you guys think?
The floor to ceiling height (before construction) is a bit more than 98". The ceiling is just staple up tile on firring strips. Above that are the joists which are 2 x 8's. The floor above this (the apartment floor) is tongue and groove pine with oak flooring on top of that. This will allow me to construct a new interleaved ceiling supported by the inner walls of the studios.
Do you recommend timber or steel framing? How many layers of sheetrock would you recommend for the walls/ceilings - is 2 enough or will more be required to give me the level of isolation needed? Would you recommend using 5/8" sheetrock for each layer or using differing thicknesses (e.g. one layer of 5/8", one of ½", etc.)?
From what I’ve gleaned from lurking here for the last few months it doesn’t seem that I’m going to need to use RC anywhere, but please let me know if I’m wrong on this.
I’m very interested in your suggestions for the what’s above the ceiling of the studios (i.e. the space between the ceiling and the floor above). Would you recommend insulating that space with fiberglass or with Roxul, and is there anything else I should do/put in there? I don’t want to jeopardize the rentability of the upstairs apartment by not isolating the studios enough - I could really use the rental income right now!
I’ve been fortunate to retain the services of a veteran sheetrocker-plaster artisan who also happens to be a very serious musician and is very willing to take his time and do things right.
If there’s anything I’m missing/screwing up on/etc. please don’t hesitate to let me know!
Thanks for taking the time to read this long post. I’m REALLY looking forward to your feedback and suggestions.
My first project--Your advice and input needed!
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dickyd
- Posts: 11
- Joined: Mon Dec 20, 2004 3:04 am
- Location: Upstate New York, USA
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knightfly
- Senior Member
- Posts: 6976
- Joined: Sun Mar 16, 2003 11:11 am
- Location: West Coast, USA
I’m planning on using double wall, double leaf construction with a floating floor (room within a room).
May be some terminology hiccups here - I'll list a few -
Wall - an entire assembly placed between two areas to be isolated from each other.
Frame - a stud frame, either metal or wood, on which some type of cladding will be fastened such as gypsum wallboard, MDF, plywood...
Layer - one thickness of a particular cladding material; 5/8 sheet rock on a stud frame is a single layer; two x 5/8 sheet rock on the same side of a frame, one on top of the other, is two layers.
Leaf - a leaf is all the mass in one location that is NOT separated by any breathable or non-solid materials - the two layers above would be one leaf.
Air gap - this can actually be air, or anything that you can blow through - any spun or compressed fiberglass or rockwool or mineral wool or slag wool insulation is considered "air", for purposes of counting leaves and air gaps. EPS or other foam insulation can NOT be blown through because it is closed cell; these are NOT worth anything in an acoustic construct because they can't be "air", and they have very little mass.
m-a-m construction - this is what you get when you use two leaves(any number of layers per leaf) with a single air space between them. Stands for Mass-Air-Mass, also known as Mass-Spring-Mass because air is a fairly stiff spring.
Given those definitions, I'm hoping you meant double framed/double leaf walls, and that you're including any existing mass when figuring how many leaves...
For the floor I was thinking of 3/4" plywood or MDF/ 5/8" sheetrock/ 7/16" OSB. Any better suggestions or improvements?
Yes, but it would depend on your existing floor construction; no mention of that, I'd need to know frame sizes, spans, layers over the frames, basically everything you told me about the ceiling. Without that info, I wouldn't recommend even adding a sheet of plywood.
However, assuming your floor is built like fort knox, I would replace the 3/4 ply with 1/2 ply over 12" centers (2x4 minimum, preferably 2x6) and then, for the same or less money, pour 3-1/2" of solid concrete over two layers of 6 mil poly over the 1/2" ply, using 2x4's as edge forms; let it cure, remove the forms, build your walls on top of that. This would give either 4" or 6" (better) air space (filled snugly with rockwool), with 1/2" ply on top and 3-1/2" of concrete over that. Concrete weighs 3 times as much as gypsum, so the equivalent mass of your floor would be about 10 inches of gypsum; this will lower the m-a-m resonance to where it needs to be for best isolation of drums and bass.
The ceiling is just staple up tile on firring strips. Above that are the joists which are 2 x 8's. The floor above this (the apartment floor) is tongue and groove pine with oak flooring on top of that. This will allow me to construct a new interleaved ceiling supported by the inner walls of the studios.
Your use of the term interleaved makes me wonder if there are cross braces in the existing ceiling (apartment floor) - if not, there should be; and these will make it harder to interleave your ceiling joists with the existing upper floor joists. You also forgot to show which direction the joists run, and their spans, btw -
From what I’ve gleaned from lurking here for the last few months it doesn’t seem that I’m going to need to use RC anywhere, but please let me know if I’m wrong on this
Probably not wrong; RC is only needed when framing members are common to both sides of the barrier. With separate frames, this isn't the case.
Do you recommend timber or steel framing? How many layers of sheetrock would you recommend for the walls/ceilings - is 2 enough or will more be required to give me the level of isolation needed? Would you recommend using 5/8" sheetrock for each layer or using differing thicknesses
I recommend timber frames, due partially to the increased tolerance of moisture content before problems arise; however, if you're commercial zoned you may have no choice but to use steel. For what you're doing, I would go for 3 layers wherever possible - it will lower m-a-m resonance which always improves things.
The benefit of dissimilar thicknesses of sheet rock is a slight improvement at coincidence frequencies, which are usually less noticeable (for music anyway) than bottom end, which is harder to get enough of; for that reason, I'd stick with the thicker stuff because the slight addition of mass will help more where it's really needed. It also makes for less confusion if you only have one thickness on the site.
I’m very interested in your suggestions for the what’s above the ceiling of the studios (i.e. the space between the ceiling and the floor above). Would you recommend insulating that space with fiberglass or with Roxul, and is there anything else I should do/put in there?
I would remove the stapled junk so it doesn't act as a third leaf, make sure there are cross braces present, and thoroughly caulk all cracks/joints in the upper subfloor from below - then fill with Roxul, put strapping across the bottoms of the joists, build your new ceiling frame, stuff with more insulation, cover with 3 layers of rock, making sure the first layer has insulation RESTING on it for damping purposes -
and don't assume (for your new ceilings) that any particular size lumber will be OK for 3 layers of rock; that's what span tables are for. 5/8 rock weighs about 2.3 pounds per sq ft, so 3 layers would run right at 7 PSF; this means you need minimum 10 pound dead load, because that calculation includes the weight of the framing also. 20 PSF dead load is safer.
If your joists run the short way of your new rooms, you'd have a joist span of 12'5" - to span this with three layers of 5/8 rock you'd need minimum 2x8's for 24" spacing of #2 and better Doug fir; use 16" centers, and you can use 2x6's - 12" centers won't let you use 2x4's, so you might as well stay with 16" centers for least headroom loss.
If there’s anything I’m missing/screwing up on/etc. please don’t hesitate to let me know!
Look in the "sticky's" section, and download the USG manual and IR-761 (Canadian document showing over 300 different wall constructs and their actual TESTED performance; it also shows fastener schedules, layering techniques, etc - I bet there's a few things your sheet rock guru may have missed too, this is just good stuff to know.
What about HVAC? Any ideas there?
The IBC lets you use rockwool as a fire blocking, your local codes may have other ideas; use this if possible wherever a solid fire block would tie two frames together rigidly;
check out kineticsnoise.com for sway brackets if needed; look under architectural links for this.
Single doors won't cut the mustard unless you want to spend $5K EACH at Overly or similar; you should re-think your entry to allow for a sound lock setup. Ask if you're not sure about this.
Oh, forgot to mention; these rooms will be very quiet, but will still sound like CRAP until you get some acoustic treatments in there; I'd keep some $$ back in the budget for that - check the acoustics forum for a few ideas.
Gotta go for now, it's 4 am here... Steve
May be some terminology hiccups here - I'll list a few -
Wall - an entire assembly placed between two areas to be isolated from each other.
Frame - a stud frame, either metal or wood, on which some type of cladding will be fastened such as gypsum wallboard, MDF, plywood...
Layer - one thickness of a particular cladding material; 5/8 sheet rock on a stud frame is a single layer; two x 5/8 sheet rock on the same side of a frame, one on top of the other, is two layers.
Leaf - a leaf is all the mass in one location that is NOT separated by any breathable or non-solid materials - the two layers above would be one leaf.
Air gap - this can actually be air, or anything that you can blow through - any spun or compressed fiberglass or rockwool or mineral wool or slag wool insulation is considered "air", for purposes of counting leaves and air gaps. EPS or other foam insulation can NOT be blown through because it is closed cell; these are NOT worth anything in an acoustic construct because they can't be "air", and they have very little mass.
m-a-m construction - this is what you get when you use two leaves(any number of layers per leaf) with a single air space between them. Stands for Mass-Air-Mass, also known as Mass-Spring-Mass because air is a fairly stiff spring.
Given those definitions, I'm hoping you meant double framed/double leaf walls, and that you're including any existing mass when figuring how many leaves...
For the floor I was thinking of 3/4" plywood or MDF/ 5/8" sheetrock/ 7/16" OSB. Any better suggestions or improvements?
Yes, but it would depend on your existing floor construction; no mention of that, I'd need to know frame sizes, spans, layers over the frames, basically everything you told me about the ceiling. Without that info, I wouldn't recommend even adding a sheet of plywood.
However, assuming your floor is built like fort knox, I would replace the 3/4 ply with 1/2 ply over 12" centers (2x4 minimum, preferably 2x6) and then, for the same or less money, pour 3-1/2" of solid concrete over two layers of 6 mil poly over the 1/2" ply, using 2x4's as edge forms; let it cure, remove the forms, build your walls on top of that. This would give either 4" or 6" (better) air space (filled snugly with rockwool), with 1/2" ply on top and 3-1/2" of concrete over that. Concrete weighs 3 times as much as gypsum, so the equivalent mass of your floor would be about 10 inches of gypsum; this will lower the m-a-m resonance to where it needs to be for best isolation of drums and bass.
The ceiling is just staple up tile on firring strips. Above that are the joists which are 2 x 8's. The floor above this (the apartment floor) is tongue and groove pine with oak flooring on top of that. This will allow me to construct a new interleaved ceiling supported by the inner walls of the studios.
Your use of the term interleaved makes me wonder if there are cross braces in the existing ceiling (apartment floor) - if not, there should be; and these will make it harder to interleave your ceiling joists with the existing upper floor joists. You also forgot to show which direction the joists run, and their spans, btw -
From what I’ve gleaned from lurking here for the last few months it doesn’t seem that I’m going to need to use RC anywhere, but please let me know if I’m wrong on this
Probably not wrong; RC is only needed when framing members are common to both sides of the barrier. With separate frames, this isn't the case.
Do you recommend timber or steel framing? How many layers of sheetrock would you recommend for the walls/ceilings - is 2 enough or will more be required to give me the level of isolation needed? Would you recommend using 5/8" sheetrock for each layer or using differing thicknesses
I recommend timber frames, due partially to the increased tolerance of moisture content before problems arise; however, if you're commercial zoned you may have no choice but to use steel. For what you're doing, I would go for 3 layers wherever possible - it will lower m-a-m resonance which always improves things.
The benefit of dissimilar thicknesses of sheet rock is a slight improvement at coincidence frequencies, which are usually less noticeable (for music anyway) than bottom end, which is harder to get enough of; for that reason, I'd stick with the thicker stuff because the slight addition of mass will help more where it's really needed. It also makes for less confusion if you only have one thickness on the site.
I’m very interested in your suggestions for the what’s above the ceiling of the studios (i.e. the space between the ceiling and the floor above). Would you recommend insulating that space with fiberglass or with Roxul, and is there anything else I should do/put in there?
I would remove the stapled junk so it doesn't act as a third leaf, make sure there are cross braces present, and thoroughly caulk all cracks/joints in the upper subfloor from below - then fill with Roxul, put strapping across the bottoms of the joists, build your new ceiling frame, stuff with more insulation, cover with 3 layers of rock, making sure the first layer has insulation RESTING on it for damping purposes -
and don't assume (for your new ceilings) that any particular size lumber will be OK for 3 layers of rock; that's what span tables are for. 5/8 rock weighs about 2.3 pounds per sq ft, so 3 layers would run right at 7 PSF; this means you need minimum 10 pound dead load, because that calculation includes the weight of the framing also. 20 PSF dead load is safer.
If your joists run the short way of your new rooms, you'd have a joist span of 12'5" - to span this with three layers of 5/8 rock you'd need minimum 2x8's for 24" spacing of #2 and better Doug fir; use 16" centers, and you can use 2x6's - 12" centers won't let you use 2x4's, so you might as well stay with 16" centers for least headroom loss.
If there’s anything I’m missing/screwing up on/etc. please don’t hesitate to let me know!
Look in the "sticky's" section, and download the USG manual and IR-761 (Canadian document showing over 300 different wall constructs and their actual TESTED performance; it also shows fastener schedules, layering techniques, etc - I bet there's a few things your sheet rock guru may have missed too, this is just good stuff to know.
What about HVAC? Any ideas there?
The IBC lets you use rockwool as a fire blocking, your local codes may have other ideas; use this if possible wherever a solid fire block would tie two frames together rigidly;
check out kineticsnoise.com for sway brackets if needed; look under architectural links for this.
Single doors won't cut the mustard unless you want to spend $5K EACH at Overly or similar; you should re-think your entry to allow for a sound lock setup. Ask if you're not sure about this.
Oh, forgot to mention; these rooms will be very quiet, but will still sound like CRAP until you get some acoustic treatments in there; I'd keep some $$ back in the budget for that - check the acoustics forum for a few ideas.
Gotta go for now, it's 4 am here... Steve
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dickyd
- Posts: 11
- Joined: Mon Dec 20, 2004 3:04 am
- Location: Upstate New York, USA
Steve-
Thanks for the in depth reply!
As far as terminology, we're on the same wavelength. Yes, I did mean double framed/double leaf walls.
Sorry I managed to leave out details regarding the orientation of certain elements in my floor plan. The top of the drawing is north. The floor and ceiling joists both run on the east-west axis. The support beams for both floors run north-south. The ceiling joist are 16" OC, B/T/W. I'm not sure if there are any cross braces there. I haven't ripped down enough of the staple up tiles to see any as of yet.
The basement ceiling is covered with 5/8" sheetrock (required by local code) and the floor above is covered with glue down carpet, so I had to do a bit of 'deconstruction' today to get an idea of the joist size and spacing and floor construction.
Joists are 2 x 10 's, 16" OC. The span is ~12'. The floor above appears to be 1 x 10 T & G, running diagonally (45 degrees) to the joists, with at least 1 layer of underlayment on top of that. I'm not sure what the joist material is - should I assume douglas fir or something else (standard pine, for example)? Do I need to try and figure out exactly what species of wood it is?
The idea of a concrete floor is really interesting. It's something I never even considered. Would the framing below the floor (the 2 x4's or 2 x 6's) still be resting on EPDM pads or would the weight of the concrete and room above just compress them to the point of uselessness?
If it doesn’t seem like pouring 3 ½” concrete floors is going to practical or feasible, how would concrete board work as a flooring material?
I’ve been talking to my plumber/HVAC guy. The building has radiator hot water heat. It would be no problem to install heat in each room. AC is another story. The place uses a large in wall air conditioner, not central AC. If you have any suggestions for what might work best in the studios I’m all ears.
Regarding sound locks, would you recommend offsetting the entrances to the two studios (the drawing shows them directly across from each other, but it would be no problem at all to move them) and then installing double doors to each room, or could/should I install a door at the western end of the corridor between the two rooms and create a sound lock in the corridor?
I definitely plan on acoustic treatments for the rooms. Making them sound good is part of the plan. I saw that you recommend mineral rock in the corners and on the ceiling. If you feel that this works I will go with this.
I anxiously await your further input. Thanks again!!
Thanks for the in depth reply!
As far as terminology, we're on the same wavelength. Yes, I did mean double framed/double leaf walls.
Sorry I managed to leave out details regarding the orientation of certain elements in my floor plan. The top of the drawing is north. The floor and ceiling joists both run on the east-west axis. The support beams for both floors run north-south. The ceiling joist are 16" OC, B/T/W. I'm not sure if there are any cross braces there. I haven't ripped down enough of the staple up tiles to see any as of yet.
The basement ceiling is covered with 5/8" sheetrock (required by local code) and the floor above is covered with glue down carpet, so I had to do a bit of 'deconstruction' today to get an idea of the joist size and spacing and floor construction.
Joists are 2 x 10 's, 16" OC. The span is ~12'. The floor above appears to be 1 x 10 T & G, running diagonally (45 degrees) to the joists, with at least 1 layer of underlayment on top of that. I'm not sure what the joist material is - should I assume douglas fir or something else (standard pine, for example)? Do I need to try and figure out exactly what species of wood it is?
The idea of a concrete floor is really interesting. It's something I never even considered. Would the framing below the floor (the 2 x4's or 2 x 6's) still be resting on EPDM pads or would the weight of the concrete and room above just compress them to the point of uselessness?
If it doesn’t seem like pouring 3 ½” concrete floors is going to practical or feasible, how would concrete board work as a flooring material?
I’ve been talking to my plumber/HVAC guy. The building has radiator hot water heat. It would be no problem to install heat in each room. AC is another story. The place uses a large in wall air conditioner, not central AC. If you have any suggestions for what might work best in the studios I’m all ears.
Regarding sound locks, would you recommend offsetting the entrances to the two studios (the drawing shows them directly across from each other, but it would be no problem at all to move them) and then installing double doors to each room, or could/should I install a door at the western end of the corridor between the two rooms and create a sound lock in the corridor?
I definitely plan on acoustic treatments for the rooms. Making them sound good is part of the plan. I saw that you recommend mineral rock in the corners and on the ceiling. If you feel that this works I will go with this.
I anxiously await your further input. Thanks again!!
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knightfly
- Senior Member
- Posts: 6976
- Joined: Sun Mar 16, 2003 11:11 am
- Location: West Coast, USA
Sorry I managed to leave out details regarding the orientation of certain elements in my floor plan. The top of the drawing is north. The floor and ceiling joists both run on the east-west axis. The support beams for both floors run north-south. The ceiling joist are 16" OC, B/T/W. I'm not sure if there are any cross braces there. I haven't ripped down enough of the staple up tiles to see any as of yet.
The basement ceiling is covered with 5/8" sheetrock (required by local code) and the floor above is covered with glue down carpet, so I had to do a bit of 'deconstruction' today to get an idea of the joist size and spacing and floor construction.
Joists are 2 x 10 's, 16" OC. The span is ~12'. The floor above appears to be 1 x 10 T & G, running diagonally (45 degrees) to the joists, with at least 1 layer of underlayment on top of that. I'm not sure what the joist material is - should I assume douglas fir or something else (standard pine, for example)? Do I need to try and figure out exactly what species of wood it is?
Your existing floor layers will be about 5 psf, the 2x10's on 16" centers will add just under 2.5 psf, so without any underside panels in place (or blocking) your dead load is around 7.5 psf; the span ratings for 2x10's on 16" centers for 12' span – 60psf live, 20psf dead. Your 5/8 wallboard under the joists adds just under 2.5 psf - This means you could add 10 psf and still meet span, assuming #2 and better Doug Fir (12'4" for 60/20 loading) – if it's pine, then even better (12'8" for 60/20) – even Hemlock fir will span 12' even under those conditions.
I must have missed that you weren't putting the floated floor on a slab; a 3.5" concrete floated floor adds about 45 psf to the floor, so not a possibility here, sorry – 2 layers of 5/8 OSB with a ¾" layer of MDF sandwiched between, on 2x6 16" centers, would weigh about 8.5 psf – this would give a 6" air gap (filled with rockwool or equiv. of course) placed over your existing floor, isolation to the basement should be about STC 49, with the LF TL @ about 32 dB. More important, this floor would lessen the flanking transmission into vertical walls, so less transfer to upstairs, ASSUMING that the walls themselves don't negate this effect.
If your wall framing MUST bear under the upper floor, this will be a major source of flanking – if possible, the best way here would be to use shorter wall framing, and put separate ceiling joists on top of those frames for the practice room ceiling – that way, you have no hard contact between framing for the rooms and the rest of the construction, other than the floor – by framing the inner walls on TOP of the floated floor, (extra pucks around the perimeter for the extra weight of both the walls AND the ceiling) you will increase the effective mass of the floor (better isolation), isolate the walls from existing floor (less flanking) and completely separate the ceiling mass from the upper (apartment) floor.
You would still need a full insulation pack between practice room ceiling and apartment floor. Depending on the effective air space between the new practice room ceiling and the old apartment floor, you might only need 2 layers of 5/8 drywall for your inner walls/ceilings.
We need to discuss how much headroom you have between the existing main floor and the ceiling frame above, so we know how to approach this for max isolation and headroom without breaking your floor, and inadvertently increasing your usable headroom ---
The idea of a concrete floor is really interesting. It's something I never even considered. Would the framing below the floor (the 2 x4's or 2 x 6's) still be resting on EPDM pads or would the weight of the concrete and room above just compress them to the point of uselessness?
Still on EPDM, only spacing needs to change to maintain approx. 15-20% compression of the elastomer. Definitely use pressure treated lumber (if your code allows this for interiors; someone somewhere said theirs did NOT)
If it doesn’t seem like pouring 3 ½” concrete floors is going to practical or feasible, how would concrete board work as a flooring material?
Materials like Wonderboard are high mass, so for that aspect they're fine – they're a little more tricky to fasten without problems from my experience though – probably best as a sandwich between two layers of OSB; again, with today's material costs the concrete would be cheaper and much higher mass, so notably better LF performance. Edit - again, your framing won't support the weight of a concrete floor.
I’ve been talking to my plumber/HVAC guy. The building has radiator hot water heat. It would be no problem to install heat in each room. AC is another story. The place uses a large in wall air conditioner, not central AC. If you have any suggestions for what might work best in the studios I’m all ears.
Try this - http://www.johnlsayers.com/phpBB2/viewtopic.php?t=1856
Regarding sound locks, would you recommend offsetting the entrances to the two studios (the drawing shows them directly across from each other, but it would be no problem at all to move them) and then installing double doors to each room, or could/should I install a door at the western end of the corridor between the two rooms and create a sound lock in the corridor?
The sound lock corridor will work best – each studio's door would then be a single leaf, so the two doors would comprise a double leaf barrier with several feet of air gap. You need to think about this though; every time someone opens a studio door while the band's blasting, you lose quite a bit of isolation between rooms (and to the rest of the building) – You would need to do a detailed drawing of each layer/stud, etc, around the entire new area – then I could tell what problems you would run into regarding flanking, leaf mass, etc -
I definitely plan on acoustic treatments for the rooms. Making them sound good is part of the plan. I saw that you recommend mineral rock in the corners and on the ceiling. If you feel that this works I will go with this.
This is the simplest first thing to do in any room; minimal carpet (crappy absorption balance) ceiling clouds, alternate live/absorbed sections on walls (with opposing surfaces opposite) (absorption opposite bare spots) – these basics will make any room sound better.
I anxiously await your further input. Thanks again!!
You're welcome, sorry I got so far behind... Steve
The basement ceiling is covered with 5/8" sheetrock (required by local code) and the floor above is covered with glue down carpet, so I had to do a bit of 'deconstruction' today to get an idea of the joist size and spacing and floor construction.
Joists are 2 x 10 's, 16" OC. The span is ~12'. The floor above appears to be 1 x 10 T & G, running diagonally (45 degrees) to the joists, with at least 1 layer of underlayment on top of that. I'm not sure what the joist material is - should I assume douglas fir or something else (standard pine, for example)? Do I need to try and figure out exactly what species of wood it is?
Your existing floor layers will be about 5 psf, the 2x10's on 16" centers will add just under 2.5 psf, so without any underside panels in place (or blocking) your dead load is around 7.5 psf; the span ratings for 2x10's on 16" centers for 12' span – 60psf live, 20psf dead. Your 5/8 wallboard under the joists adds just under 2.5 psf - This means you could add 10 psf and still meet span, assuming #2 and better Doug Fir (12'4" for 60/20 loading) – if it's pine, then even better (12'8" for 60/20) – even Hemlock fir will span 12' even under those conditions.
I must have missed that you weren't putting the floated floor on a slab; a 3.5" concrete floated floor adds about 45 psf to the floor, so not a possibility here, sorry – 2 layers of 5/8 OSB with a ¾" layer of MDF sandwiched between, on 2x6 16" centers, would weigh about 8.5 psf – this would give a 6" air gap (filled with rockwool or equiv. of course) placed over your existing floor, isolation to the basement should be about STC 49, with the LF TL @ about 32 dB. More important, this floor would lessen the flanking transmission into vertical walls, so less transfer to upstairs, ASSUMING that the walls themselves don't negate this effect.
If your wall framing MUST bear under the upper floor, this will be a major source of flanking – if possible, the best way here would be to use shorter wall framing, and put separate ceiling joists on top of those frames for the practice room ceiling – that way, you have no hard contact between framing for the rooms and the rest of the construction, other than the floor – by framing the inner walls on TOP of the floated floor, (extra pucks around the perimeter for the extra weight of both the walls AND the ceiling) you will increase the effective mass of the floor (better isolation), isolate the walls from existing floor (less flanking) and completely separate the ceiling mass from the upper (apartment) floor.
You would still need a full insulation pack between practice room ceiling and apartment floor. Depending on the effective air space between the new practice room ceiling and the old apartment floor, you might only need 2 layers of 5/8 drywall for your inner walls/ceilings.
We need to discuss how much headroom you have between the existing main floor and the ceiling frame above, so we know how to approach this for max isolation and headroom without breaking your floor, and inadvertently increasing your usable headroom ---
The idea of a concrete floor is really interesting. It's something I never even considered. Would the framing below the floor (the 2 x4's or 2 x 6's) still be resting on EPDM pads or would the weight of the concrete and room above just compress them to the point of uselessness?
Still on EPDM, only spacing needs to change to maintain approx. 15-20% compression of the elastomer. Definitely use pressure treated lumber (if your code allows this for interiors; someone somewhere said theirs did NOT)
If it doesn’t seem like pouring 3 ½” concrete floors is going to practical or feasible, how would concrete board work as a flooring material?
Materials like Wonderboard are high mass, so for that aspect they're fine – they're a little more tricky to fasten without problems from my experience though – probably best as a sandwich between two layers of OSB; again, with today's material costs the concrete would be cheaper and much higher mass, so notably better LF performance. Edit - again, your framing won't support the weight of a concrete floor.
I’ve been talking to my plumber/HVAC guy. The building has radiator hot water heat. It would be no problem to install heat in each room. AC is another story. The place uses a large in wall air conditioner, not central AC. If you have any suggestions for what might work best in the studios I’m all ears.
Try this - http://www.johnlsayers.com/phpBB2/viewtopic.php?t=1856
Regarding sound locks, would you recommend offsetting the entrances to the two studios (the drawing shows them directly across from each other, but it would be no problem at all to move them) and then installing double doors to each room, or could/should I install a door at the western end of the corridor between the two rooms and create a sound lock in the corridor?
The sound lock corridor will work best – each studio's door would then be a single leaf, so the two doors would comprise a double leaf barrier with several feet of air gap. You need to think about this though; every time someone opens a studio door while the band's blasting, you lose quite a bit of isolation between rooms (and to the rest of the building) – You would need to do a detailed drawing of each layer/stud, etc, around the entire new area – then I could tell what problems you would run into regarding flanking, leaf mass, etc -
I definitely plan on acoustic treatments for the rooms. Making them sound good is part of the plan. I saw that you recommend mineral rock in the corners and on the ceiling. If you feel that this works I will go with this.
This is the simplest first thing to do in any room; minimal carpet (crappy absorption balance) ceiling clouds, alternate live/absorbed sections on walls (with opposing surfaces opposite) (absorption opposite bare spots) – these basics will make any room sound better.
I anxiously await your further input. Thanks again!!
You're welcome, sorry I got so far behind... Steve
Last edited by knightfly on Sat Jan 22, 2005 7:10 pm, edited 1 time in total.
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sharward
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A/C Idea
Have you considered a "ductless/mini-split" system, such as Mitsubishi's "Mr. Slim" line? It's kind of like a window air conditioner split into two parts (indoor and outdoor). You could get a dual system -- one outdoor unit and two indoor units.
They're somewhat expensive, and there may be some drawbacks, as discussed elsewhere on this forum... But there's minimal penetration through the walls, which is bound to help in terms of your isolation goals.
I'm planning to use one for my own project this year.
They're somewhat expensive, and there may be some drawbacks, as discussed elsewhere on this forum... But there's minimal penetration through the walls, which is bound to help in terms of your isolation goals.
I'm planning to use one for my own project this year.
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dickyd
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Steve,
My further thanks and appreciation! Here is some clarification and answers to questions you raised in your last reply.
We need to discuss how much headroom you have between the existing main floor and the ceiling frame above, so we know how to approach this for max isolation and headroom without breaking your floor, and inadvertently increasing your usable headroom ---
The distance from the existing floor to the bottom of the existing ceiling frame is ~98". The ceiling joists are 2 x 8's.
The sound lock corridor will work best...
I’ve posted a couple of different concepts for the rehearsal space area construction. Is either one of these the right idea for the sound lock, or am I missing something in my understanding of ‘room within a room’ construction or of double leaf construction?
The first drawing shows the corridor as the air space between the two rooms. This concept raises the question of the walls in the corridor - the side of the wall facing into each room would be sheetrock, but the side facing into the corridor would have to be ‘open’ (i.e. exposed framing/mineral rock) which seems kind of unusual.
The second drawing shows double walls all the way around, but does this create a quadruple leaf effect between rooms, or does the corridor width/airspace negate that?
If your wall framing MUST bear under the upper floor, this will be a major source of flanking – if possible, the best way here would be to use shorter wall framing, and put separate ceiling joists on top of those frames for the practice room ceiling
That’s my intention!
Thanks again for your input. You don’t know how helpful you’ve been to clarifying my plans.
My further thanks and appreciation! Here is some clarification and answers to questions you raised in your last reply.
We need to discuss how much headroom you have between the existing main floor and the ceiling frame above, so we know how to approach this for max isolation and headroom without breaking your floor, and inadvertently increasing your usable headroom ---
The distance from the existing floor to the bottom of the existing ceiling frame is ~98". The ceiling joists are 2 x 8's.
The sound lock corridor will work best...
I’ve posted a couple of different concepts for the rehearsal space area construction. Is either one of these the right idea for the sound lock, or am I missing something in my understanding of ‘room within a room’ construction or of double leaf construction?
The first drawing shows the corridor as the air space between the two rooms. This concept raises the question of the walls in the corridor - the side of the wall facing into each room would be sheetrock, but the side facing into the corridor would have to be ‘open’ (i.e. exposed framing/mineral rock) which seems kind of unusual.
The second drawing shows double walls all the way around, but does this create a quadruple leaf effect between rooms, or does the corridor width/airspace negate that?
If your wall framing MUST bear under the upper floor, this will be a major source of flanking – if possible, the best way here would be to use shorter wall framing, and put separate ceiling joists on top of those frames for the practice room ceiling
That’s my intention!
Thanks again for your input. You don’t know how helpful you’ve been to clarifying my plans.
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knightfly
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The double walls (without a second door) in the lower of the two drawings will only WEAKEN the iso between the two rooms by adding leaves - putting a second door in each location would lessen iso between the rooms too, but if you built extra mass into them you could get back most of the LF isolation you lose from multiple leaves - which way you go on this (and maybe 1 or 2 other points) will depend on your answer to the following -
How disruptive will it be to your business (outside the practice rooms) if, every time someone opens either of the two airlock doors OR either practice room door, you get a burst of noise into the rest of the business area? Also, how important is it that NEITHER practice area gets disturbed if the OTHER practice area's doors get opened while someone is thrashing drums inside?
(drum roll) and the answer is...
Steve
How disruptive will it be to your business (outside the practice rooms) if, every time someone opens either of the two airlock doors OR either practice room door, you get a burst of noise into the rest of the business area? Also, how important is it that NEITHER practice area gets disturbed if the OTHER practice area's doors get opened while someone is thrashing drums inside?
(drum roll) and the answer is...
Steve-
dickyd
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(drum roll) and the answer is...
Steve-
I don't think it will be too disruptive.
First, it's only going to be very short periods of time.
Secondly, hey, it's a music store. There's bound to be some noise -- goes along with the territory.
Third, maybe it will drown out the kid in the corner trying to reproduce the latest masterpiece from Linkin Park, the umpteenth version of Stairway To Heavan, etc., etc..
Steve-
I don't think it will be too disruptive.
First, it's only going to be very short periods of time.
Secondly, hey, it's a music store. There's bound to be some noise -- goes along with the territory.
Third, maybe it will drown out the kid in the corner trying to reproduce the latest masterpiece from Linkin Park, the umpteenth version of Stairway To Heavan, etc., etc..
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knightfly
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dickyd
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In that case, the top drawing is your baby...
I figured that was the answer. Which brings me to the next question...
My assumption is that the walls in the corridor (the surfaces one sees when inside the corridor) would be 'open' - i.e. exposed framing and Roxul. If this is indeed the case, would you recommend covering those exposed surfaces with, perhaps, burlap, or even better yet some type of screening material covered with burlap? Would you have another suggestion? I'm assuming that this sort of arrangement would not be considered adding any additional leaves.
I'm also figuring that the corridor would need to be part of the room within a room configuration--same floated floor and second ceiling as the two rooms. Would this sound lock arrangement still be optimal for minimizing as much as possible transmission and flanking to the upstairs?
Once again Steve, my heartfelt thanks for your replies. I really can't begin to tell you how helpful your input has been!
I figured that was the answer. Which brings me to the next question...
My assumption is that the walls in the corridor (the surfaces one sees when inside the corridor) would be 'open' - i.e. exposed framing and Roxul. If this is indeed the case, would you recommend covering those exposed surfaces with, perhaps, burlap, or even better yet some type of screening material covered with burlap? Would you have another suggestion? I'm assuming that this sort of arrangement would not be considered adding any additional leaves.
I'm also figuring that the corridor would need to be part of the room within a room configuration--same floated floor and second ceiling as the two rooms. Would this sound lock arrangement still be optimal for minimizing as much as possible transmission and flanking to the upstairs?
Once again Steve, my heartfelt thanks for your replies. I really can't begin to tell you how helpful your input has been!
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knightfly
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My assumption is that the walls in the corridor (the surfaces one sees when inside the corridor) would be 'open' - i.e. exposed framing and Roxul. If this is indeed the case, would you recommend covering those exposed surfaces with, perhaps, burlap, or even better yet some type of screening material covered with burlap? Would you have another suggestion? I'm assuming that this sort of arrangement would not be considered adding any additional leaves.
Or, you could frame with 2x4, put 3 layers of gypsum on the corridor side, half fill with roxul, cloth cover the insides, then put 1/4" pegboard with 1/8" holes on 1" centers, and have a helmholtz wall at around 200 hZ which would help tame mid-bass modes - your dimensions have a slight boost in modes around that frequency.
If the corridor needed absorption also, to help kill leakage a bit, you could add a few wall-hung absorbers covered with some kind of "mural" cloth for both decorative and acoustic purposes.
I'm also figuring that the corridor would need to be part of the room within a room configuration--same floated floor and second ceiling as the two rooms. Would this sound lock arrangement still be optimal for minimizing as much as possible transmission and flanking to the upstairs?
Most likely - look at your design, pretend you are a sound, and try to get from the sound lock (or either room) into the upstairs apartment; if you have to pass through mass, air(insulated) and another mass, then it's just right. Only way to improve on this is more mass, wider gap, better decoupling between the two masses... Steve
Or, you could frame with 2x4, put 3 layers of gypsum on the corridor side, half fill with roxul, cloth cover the insides, then put 1/4" pegboard with 1/8" holes on 1" centers, and have a helmholtz wall at around 200 hZ which would help tame mid-bass modes - your dimensions have a slight boost in modes around that frequency.
If the corridor needed absorption also, to help kill leakage a bit, you could add a few wall-hung absorbers covered with some kind of "mural" cloth for both decorative and acoustic purposes.
I'm also figuring that the corridor would need to be part of the room within a room configuration--same floated floor and second ceiling as the two rooms. Would this sound lock arrangement still be optimal for minimizing as much as possible transmission and flanking to the upstairs?
Most likely - look at your design, pretend you are a sound, and try to get from the sound lock (or either room) into the upstairs apartment; if you have to pass through mass, air(insulated) and another mass, then it's just right. Only way to improve on this is more mass, wider gap, better decoupling between the two masses... Steve
Last edited by knightfly on Tue Feb 01, 2005 3:59 am, edited 1 time in total.
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dickyd
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Or, you could frame with 2x4, put 3 layers of gypsum on the corridor side, half fill with roxul, cloth cover the insides, then put 1/4" pegboard with 1/8" holes on 1" centers...
Neat idea! Does this mean that, for example, I would place the gypsum on the 'inside' of the frame of each room on the other three walls and on the 'outside' of the frame on the corridor wall? (i.e. three 'standard' walls and one 'inside-out' wall) Also, I'm not sure what you mean by "half fill".
One thing I neglected to clarify with you-would you recommend three layers of gypsum all around (both outside and inside or maybe just inside), [Edit: just on certain walls], or will two layers be more than sufficient.
Thanks once again for taking the time to educate me!
Neat idea! Does this mean that, for example, I would place the gypsum on the 'inside' of the frame of each room on the other three walls and on the 'outside' of the frame on the corridor wall? (i.e. three 'standard' walls and one 'inside-out' wall) Also, I'm not sure what you mean by "half fill".
One thing I neglected to clarify with you-would you recommend three layers of gypsum all around (both outside and inside or maybe just inside), [Edit: just on certain walls], or will two layers be more than sufficient.
Thanks once again for taking the time to educate me!
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knightfly
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Three layers behind the trap wall, to compensate for narrower air space in wall and the few dB TL loss the trap will cause in the wall; all other leaves two layers will be fine.
I edited both your and my posts to change "leaves" to "layers", just to avoid confusion -
I started a more detailed sketch of wall detail, but ran out of time; I'll post it later as soon as I figure out how you could actually BUILD it , and in what order... Steve
I edited both your and my posts to change "leaves" to "layers", just to avoid confusion -
I started a more detailed sketch of wall detail, but ran out of time; I'll post it later as soon as I figure out how you could actually BUILD it
, and in what order... Steve-
dickyd
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I started a more detailed sketch of wall detail, but ran out of time; I'll post it later as soon as I figure out how you could actually BUILD it , and in what order...
Steve,
I figured you may have gotten busy with a number of life’s more pressing issues, so I came up with a diagram of what I think you intended with your suggestions. I’ve shown the southwest corner of the ‘upper’ (northern) rehearsal studio. Is this what you had in mind?
I’m still not sure what you mean by half-fill. Could you elaborate a bit?
Thanks much!
, and in what order... Steve,
I figured you may have gotten busy with a number of life’s more pressing issues, so I came up with a diagram of what I think you intended with your suggestions. I’ve shown the southwest corner of the ‘upper’ (northern) rehearsal studio. Is this what you had in mind?
I’m still not sure what you mean by half-fill. Could you elaborate a bit?
Thanks much!
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knightfly
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Close, except there's no stud support for the SW end of the pegboard - and the "half fill" is what you do for helmholtz traps - the half of the cavity depth AWAY from the perforated board is insulation, the half TOWARD the perf board is AIR, then cloth behind the perf board stretched over the frame, and finally the perf board...
You can fill the trap more, it will widen the response curve and lessen the absorption somewhat - in most cases this isn't a bad thing.
If you can, find a source of "impaling clips", and glue them to the back of the trap - then you can impale the insulation on the clips to keep it in place... Steve
You can fill the trap more, it will widen the response curve and lessen the absorption somewhat - in most cases this isn't a bad thing.
If you can, find a source of "impaling clips", and glue them to the back of the trap - then you can impale the insulation on the clips to keep it in place... Steve