Hi to all:
Been lurking for a few days on this forum, reading past posts (and the ‘stickies’ and reference sections).
Just registered last nite, and am now posting about my proposed project.
(to try to save time, I’ve tried to ‘bullet’ stuff as much as I could).
Geographic region:
- MA, on North Shore of Boston.
Community:
- Suburban, residential, family.
- Privately-owned
Proposed studio/room location:
- Basement
- Exact location within basement has some flexibility
- Project start date: started! (Construction imminent)
Main existing building:
- one-story ranch house
- full basement
- NG forced-air furnace, NG water heater, full laundry (gas & electric) in basement
- Poured concrete basement floor and walls (full-height to sills)
- Wooden-framed (softwood) upper-level; hardwood (red oak) floors; sheet-rocked walls and ceilings
- 10,000 ft2 lot size; 1500 ft2 living space (excluding basement)
- Ca. 1959-60 construction date
Studio/room proposed purposes:
- (mainly) acoustic & low-level electric instrument rehearsal and recording
- Vocal rehearsal and recording
- Rarely, if ever: drum kits, or large amplifiers.
- Home theater and entertainment
- 90 db, presumed maximum SPL (Occasionally 100 db? How loud can I sing without amplification?)
- when not recording or rehearsing (majority of time), isolation of room NOT required (doors/windows can open for ventilation)
- NEED to be isolated from floor above when I sing (yes, it's that bad, lol); that is, I don't want anybody in the room above to hear me
Basement specs:
- Height (from poured concrete floor to bottom of joists): 7’3”
- Poured concrete walls extend from floor to sills
- 6 x 8 center beam, with filled steel columns spaced every 8 feet along beam.
- Joists (above): 2 x 8; 16” OC; 12 foot spans from sills to center beam; crossed bracing straps
- Sub-floor (above): 1 x 8 planks
- Dry (no uncontrolled water issues (2 sumps)); dehumidified
- Very cool, even in summers (most of basement is well below grade)
Basic proposed studio/room specs:
Dimensions:
- Floor: 14’ x 20’ (approximate outside); 12’6” x 18’6” (approximate inside)
- Ceiling: 6’ 8” (approximate inside; one area 6’ 2”, to accommodate heating ducts) –
- 2 sides of studio/room to be directly along poured concrete basement wall; the other 2 sides adjacent to the remaining space of basement (one wall has an outer adjacent, unattached stair case leading to the main floor)
- One entrance way (to main basement, 5 feet from outside basement entrance)
- 2 windowed areas, along one concrete wall, facing outside ( approximately 17 by 32 inches, spaced 10 feet apart)
Construction:
- Wooden-framed, double-walls, double-ceilings; 2-layers 5/8” sheet-rock (or 3 layers ½” Durock) per leaf (this may depend on location)
- Double-walls, even along the concrete (including outer leaf sheet-rock, approximately one to two inches from poured concrete wall)
- (2) 2 x 3 parallel base plates, spaced 1” apart
- 2 x 4 studs, 16” OC
- 2 x 3 top plates (inner top plate height lower to accommodate inner ceiling)
- 4 trusses: 2 resting on outer wall top plate; 2 resting on inner wall top plate , bisecting length of room, 2 on each side of main heating duct; longest span 13 feet
- Each truss constructed from 2 parallel (horizontal on edges) 2 x 6 ‘s (or 2 x 4 ‘s ?), separated by short pieces (about 9 inches) of 2 x 4 studs, all secured (somehow) with metal bracing
- 2 x 4 (or 2 x 6) outer ceiling joists; longest span 11 feet (on one side of ducts)
- 2 x 3 inner ceiling joist; longest span 10 feet
- Floor to remain concrete (may be painted?)
- Double, isolated, solid, entrance doors (both standard width, but different heights); one attached to inner wall, one attached to outer wall
- Double (opening) windows; 12 inches between each window pane; multi-layer (4?) sheet-rock for window soffits (but leaving one or one-half inch gap between wall leaves.
- Fiberglass insulation between wall and ceiling leaves, and between outer ceiling joists and main floor joists
- Electrical supply would be fed via long, doubled-back, isolated conduit; all lighting and wiring will be surface-mount via conduit, surface boxes, table fixtures, or track lighting (or maybe plug-mold)
Misc.:
- Furnace, water heater, meters, TV cable, water supply or lines, laundry, electrical panel, and outside door, are NOT near proposed studio/room location
- Telephone service cable is in corner, above proposed location; will be conduit-ed along sill past the studio/room
- A main furnace duct runs below existing joists, and above proposed location, nearly bisecting it.
- 2 between-joist, heating ducts are above proposed space, each beginning above main duct and ending on opposite walls
- Nothing is below concrete floor for except solid earth (therefore no treatment?)
Concerns and (some) potential problems:
Spans of ceiling joists:
- 2 x 4, or 2 x 6 (?) ; no ‘extra’ room for 2 x 6 joists (especially inner ceiling joists)
- If joists are of oak, maple, yellow pine, metal, etc., could 2 x 4 joists be sufficient?
- If joist spacing is decreased, could 2 x 4 joists be sufficient?
- Conflicting numbers from span ‘calculators’
- Is ‘live load’ of any consideration?
- Does ‘dead load’ include joist weight also (not just external load)? Why?
Floor:
- Any problem leaving floor concrete exposed, since only solid earth is below it?
Windows:
- Is leaving existing basement window and glass (thin) a possibility?
- Thickness of inner window?
- Should I double-leaf the soffits or leave them ‘open’ to the leaf space?
Leaf spacing:
- How much of a compromise is the decreased leaf spacing of the ceiling or of the areas surrounding ducts?
- Will putting an outside wall within 2 inches of concrete wall constitute an additional leaf, or otherwise be a compromise (even if there is no ‘seal’ between the sheet-rock and concrete)?
Other thoughts:
The ‘adding extra leaf’ concept:
- From looking at all the pictures of how adding extra inner leaves decreases performance, I noticed that none of these leaves pictured a ‘free-floating’ extra leaf; indeed, all of the permutations had sheet-rock affixed to the studs which supported the 2 original leaves; having the sheet-rock attached to the same studs itself could probably a big factor in the performance decrease.
- I’m wondering: if the total space between the original leaves remained the same, and if the extra leaf was not attached to the either original leaves, what would the performance be (not that I’m even considering doing it). Of course, this additional leaf must isolate both compartments, otherwise wouldn’t it really then be just a ‘baffle’?
Span calculators:
- I had always understood that most hardwoods, such as oak, maple, birch, etc. (and even some softwoods), had greater strength than spruce, balsam, or pine; why does that linked span calculator (from several posts on this forum) actually end up DECREASING the maximum allowable span when one changes from, for example, spruce to white oak or maple? Is it more of a deflection issue than of strength? For me, it is counterintuitive.
- I found at least 2 span charts that list an apparently higher maximum span for the same input criteria, than does that span calculator – I don’t understand why this is so (other than the possibility of different regional regulations being used).
thanx,
Kenni
PICTURE DESCRIPTIONS:
(NOTE THAT ALL STUDS AND INSULATION SEEN ARE FROM OLD CONSTRUCTION AND WILL BE TORN DOWN)
FIRST PICTURE:
Shows the 2 biggest ‘meanies’, the 6 x 8 center-beam and the main heating duct (drops 10 inches from floor joists).
On the concrete walls is OLD construction that will be torn down shortly.
Above the beam are 2 x 8 floor joists, and really not much room to put in 2 x 6 isolated ceiling joists (for the outer leaf), so I’m scrambling to find an alternative (possibly ‘sistering’ smaller metal or wood 2 x 4’s to gain span strength).
SECOND PICTURE:
Here is view of the top of the existing concrete wall and floor joists.
Top of the concrete is only 3 ½ inches from the bottom of the floor joists.
Top plate and studs you see are OLD work and will be removed.
NEW top plates for the outer leaf of the wall will be in approximately same position, although 1 inch below the floor joists (and not attached).
Note that the door will not be within the studio/room; the communicating double doors to the studio/room will be about 4 feet opposite this door.
THIRD PICTURE:
Another shot of the floor joists near a concrete wall.
The white telephone line is an approximately the same position as the outer leaf top plate would be.
Note the OLD work studs (attached directly to the floor joists!) and insulation, that will be removed before new construction begins.
FOURTH PICTURE:
Cross-bracing between the 2 x 8 floor joists.
The big reasons I would like to avoid using 2 x 6’s as outer ceiling joists between them are these braces, the 2 between joist-heating ducts, and that the bottom of the floor joists is just 7’3” from the concrete floor.
FIFTH PICTURE:
Here is a wider shot of the 6 x 8 beam, the main heating duct, the two between-joist heating ducts, the steel post, and the 2 x 8 floor joists.
Note the OLD work strapping, which will soon be removed (as will the old studs and insulation).
SIXTH PICTURE:
Closer view of the pole, the beam, the main duct, the between-joist ducts, and the 2 x 8 floor joists.
The beam and main duct will be ‘ducked’ by both leaves of the ceiling.
I’m planning on building trusses that bridge between the walls (4 trusses total).
These would be placed on both sides of the beam and main duct area (2 on each side), and would be used as support for each of the ceiling leaf’s joists.
The steel pole will be also enclosed within double-walling, and this will be used as center-support for the trusses (all isolated, of course).
****
I will be taking pics of my floor plans and detail diagrams for construction ideas.
I will also be posting more pics of other things, like where the stair case is, etc.
PLEASE FEEL FREE TO MAKE ANY COMMENTS. PLEASE PLEASE.
Basement studio-room project in Boston area
Originally posted at johnlsayers.com, topic 5980.
Below is a drawing of the cross-section of what the walls along the concrete might look like.
It shows a few things that are causing me questions:
1.) Third leaf?
There would be an UN-ISOLATED air gap between the outer stud wall sheet-rock and the concrete wall.
a.) Would this constitute a third leaf even if it is open to the rest of the basement (it is not sealed off, and air can travel between it and the entire basement)?
b.) Would it be better to incorporate the poured concrete walls AS the outer leaf? If that is true, it would seem a difficult matter of sealing the other outer walls to the concrete (what I mean is that the intersecting new walls need to seal against the concrete, AND there would still be a small gap ABOVE the concrete wall that needs to be sealed-off).
2.) Depth of ceiling joists?
I would really prefer to juse something close to 4 inch depth, than to use 6 inches, because I don't have lots of room between the existing floor joists, AND I can't really afford to lose any ceiling height in the proposed room.
a.) Isn't it possible to sister two wooden or steel 2 x 4's together and gain maximum span strength? I do have room to spare for that.
b.) What would be better to use wood or steel? If wood, is it possible to use a stronger wood, say oak or maple, and gain maximum span strength that way?
It would seem to me that if 2 steel studs were boxed together considerable strength could be gained:
(The following is a link of Steel Stud Manufacturers Association Technical Information; there are diagrams showing how to 'stiffen' a stud or joist by boxing or back-to-back joining of 2 members; page 42 gives span specs)
http://www.rinker.com/steelcon/download ... mation.pdf
*** UPDATE: I no longer plan to do the ceiling or walls like this, as it is obviously triple-leaf; see later posts ***
Aloha and welcome to the forum, Kenni :D
Congrats on your studio build! Great intro and info provided. Please don't be discouraged if there hasn't been any responses yet. Some of the questions/issues of your build require more knowledge/experience than most of us have, and Steve/Knightfly (our senior moderator) has an incredible work schedule/work load with his regular job before having the chance to respond to some of the posts. So hang in there. :wink:
In the meantime, looking forward to your floorplan and build!
Aloha 8)
thanx Kendale.....
At least I will not have to contend with a volcano or any earthquakes (or hurricanes, for the most part).
I realize that I have to supply more detail diagrams and a floor plan, plus some more pics that will give the people 'who know' more to go on (and an easier time at it too).
For now, does anyone know how an outer leaf should be done when it would be sitting right next to a poured concrete wall (within 2 inches)?
I'm not the least bit worried with transmission THROUGH the concrete wall (as it IS poured concrete), and there is only the outdoor earth behind it (up to 2/3 or more of the wall height), and there are NO neighbors in close proximity, then I could better 'finalize' my plans.
So I'm thinking that incorporating the concrete wall INTO the outer leaf should be okay; however, this might make it difficult to a seal with the other walls.
On the other hand, building a stud wall next to the concrete (within 2 inches, but NOT sealing-in an additional leaf) would make it easier to get good seal with the other walls.
I just don't know enough about whether that would create a 'quasi-leaf'.
If I could only get answers to this question, and the one about sistering joists in order to be able to use shorter joist heights (2 x 4 versus 2 x6).....
K
Aloha Kenni,
Have you considered using John's inside out design? Aloha 8)does anyone know how an outer leaf should be done when it would be sitting right next to a poured concrete wall (within 2 inches)?
Hi Kendale: Hmmm, interesting.... although there are a couple of things that I don't want or can't do. I don't plan on floating any floor at all; just keeping the plain concrete floor (of course I will seal it with appropriate paint, and throw some sort of carpeting over). One big reason is that I don't have the ceiling height to 'lose'. Another thing is that I will not be having any drum kits or large bassy amplifiers in the room (thus not a large amount of 'impact' sound transmission). And there is nothing but solid poured concrete and earth below it, so I'm 'assuming' that very little transmission of sound will occur through the floor (and much rather would worry about the walls and ceiling). One other thing I see in that design diagram is the 'resonator'; is that used as a bass sink? Finally I would not know how to address the upper part of the wall -- that is, the 3.5 inches between the top of the concrete wall and the (above floor) floor joists; I need a really good double-wall treatment (mass-air-mass) for that part. I will have to examine that design a few more times until I 'get it'. Maybe I can find the links for the posts so I can understand it better. thanx, KAloha Kenni,Have you considered using John's inside out design? Aloha 8)does anyone know how an outer leaf should be done when it would be sitting right next to a poured concrete wall (within 2 inches)?
I hope the following picture explains what I plan to do in order to double-leaf the ceiling.
Again, since the above floor and floor joist don't touch the proposed outer leaf, and since there is free flow of air movement over that leaf, I'm thinking that this would be okay.
I don't know enough about whether -- in some way -- that above floor and floor joists would constitute a 'true' leaf.
Any thoughts anyone?
thanx,
K
*** UPDATE: I no longer plan to do the walls and ceiling like the below pic, as this is too 'third-leafy', as well as excessive; see later posts for 'new' ideas ***
Luftweg,
Welcome to the forum, I had read your comments on another thread and meant to post here sooner but... I saw the length of your 1st post... and good job man. It takes some of us a while to read through things, once we get the time.
OK so your ceiling pic is definatly a 3 leaf wall, hands down. :shock:
Andy is currently dealing with his ceiling near the end of his thread:
http://www.johnlsayers.com/phpBB2/viewt ... &start=210
Basically you'll want to add cut up peices of drywall in between the ceiling joists and use cleats to hold them up against the ceiling/floor. Something like near the end of this page:
http://www.saecollege.de/reference_mate ... /Walls.htm
BUT you will have to figure out the load weight of your existing ceiling/floor joists before you make any plan. Green Glue although expensive can make 2 layers of drywall almost equal to 4 layers, and makes good cents on ceilings where load is critical. :roll:
I keep on refering in posts to Rod's Book in the stickies.... he has pages dedicated to this exact ceiling construction and how to do it correctly almost step by step.
Another factor with ceiling is if you have the height to use seperate inner room joists for the inner leaf of ceiling. From you pic I presume you have... again span/weight is important... wait ... no you don't at 7'3" slab to joist. Code for room height is 7'. Hmmm, I'm gonna stop on this topic for now. :roll:
How I wish I had solid concrete wall and not hollow Cinder Block for my own studio.
Your Concrete wall should (is) your outer leaf. Based on your sound isolation requirements I'm going to guess you'll want a 2x4 wall built 1" to 3" away from the concrete wall with 2 or 3 layers of 5/8" drywall on the inner leaf, inner side.
Your right on not needing the floated sub floor, expencive and easy to screw up.
The resontor wall and inside out wall in Kendales post from John.
Inside out walls are built on the ground, rasied into position to be squared, lowered back down and then drywall goes on. Then it has to be lifted back into place, and it would be really, really heavy. With all edges of the drywall not in reach you can not caulk it. Sound isolation is less with a inside out wall, although valuable space will be gained if using a slot wall inside the inside out wall.
The slot resonator shown would be a low-mid, mid absorber as well as a very good side wall diffuser and if built on side walls splayed will create a RFZ zone. A very useful acoustic tool, if built correctly. BUT even with all the "holes" a slot wall still creates triple leaf effect which must be taken into consideration. I am planning on putting one next to my exterior CB wall (cavities filled with sand), I'm still considering if I'll use another on a new 2x4 double (exterior) wall, and I'm definatley not using any slot wall where sound isolation is important.
BUT sometimes tripple leaf can't be avoided so it seems studio builders do there best to work around it.
And remember more mass or more air = more isolation. Inside out walls take away air and make mass on inner leaf a back breaker. :shock:
Marc :twisted:
I just want to echo Marc's sentiments on the great job documenting the details in your introductory post, Luftweg. Awesome.
I'm afraid that's all I have time to do on it though... :lol: Life is crazy busy for me right now........ Getting ready to go to Hawaii next week, trying to pull forms off my concrete when time permits, treating an injured pet, rehearsing for a gig at the end of the month, and oh yeah, this thing they call employment now and then... ;-)
Please be patient...... I know your project construction is imminent, but you'd be wise to slow down, learn as much as you can, and wait for the feedback you'll need to proceed with confidence.
--Keith :mrgreen:
(Sorry for the hit and run.)
Perhapas you have gone too much in detail for the first post?
I have seen your post before I joined the forum and I didnt had the concetration to reed it all. I have read it last night, and its very well written, but from my point of view there is little I can gain from studying your case. ... That is, until you get some quality replies.
Maybe you could draw some more attention with a simpler post?
Anyway dont feel bad about it, it takes time and patience.
Hope your project turns out fine.
keep in touch, Medo
I have to disagree with the "too much detail" concept. There are so many threads on this forum where Steve and others have had to drag details out one post at a time. It's time consuming and frustrating for all parties.
I think we're just in one of those time periods where Steve and others (myself included) are just so busy that our ability to contribute is very limited. These are the times that we need to be especially patient, yet also not be somewhat assertive at times.
Please don't be discouraged and let's help reinforce the "give us lots of details up front" message that Steve sends regularly on this forum. :D
--Keith :mrgreen:
Aloha,
Sorry about that. Here's the link: http://www.saecollege.de/reference_material/index.html (click on construction tab at left - walls and ceilings at top) Aloha 8)I will have to examine that design a few more times until I 'get it'. Maybe I can find the links for the posts so I can understand it better.
Hi Guit-Dad:
thanx for the reply...
Actually, although I definitely see that it could be considered a 'third leaf' because of where it lies, I'm not at all convinced (yet) that it is a TRUE third leaf. As far as I'm currently being led to understand, a TRUE leaf is formed when an air space is sealed-in. My original picture doesn't show that the ends (above the outer (2nd) leaf) are open to the rest of the basement; see the new picture below. If there is no seal between the above floor joists or floor, then it is not quite the same thing as a TRUE leaf. Remember, air can freely move around the the 2 leaf system, between the 'third leaf' floor and floor joists and circulate with the air in rest of the basement. This would almost HAVE to have some effect. **** I HAVE YET TO HEAR ANY EXACT DEFINITION OF, OR WHAT CONSTITUTES, A 'TRUE' LEAF, or what the effects would be on sound transmission if it were NOT a 'true' leaf (e.g., if it's not sealed-in, if the air gap is huge, etc) **** If what you say IS true, and the above floor and joist constitutes a leaf, then ALL the walls -- including the ones where the concrete wall will be 15 to 25 feet away -- would also be three leaf walls. The only real differences would be the proximity of the leaves, and the size of the air gap. So, I hope I'm being understood when I repeat: There must be limits to the 'third leaf effect', AND there must be an exact definition of what constitutes a TRUE third leaf. I think alot of this is becoming like a 'taboo', or 'folklore'. People see 3 things next to each other and automatically think 'three leaves'. Sometimes that may be true, other times it may not, and still other times there might be a middle ground (my so-called 'quasi-third-leaf'). IF there is a middle ground, then one has to try to determine to what degree there is a third-leaf effect. It may just be that if the 'third' leaf is NOT sealed-in, not physically connected, AND/OR is significantly far away, then other factors could become more dominating. Again, a direct answer to the 'big' question remains to be answered.Luftweg, ..... OK so your ceiling pic is definatly a 3 leaf wall, hands down.
Thanx. I will take a look.Andy is currently dealing with his ceiling near the end of his thread: http://www.johnlsayers.com/phpBB2/viewt ... &start=210
thanx, will take a look (think I've seen it before though).Basically you'll want to add cut up peices of drywall in between the ceiling joists and use cleats to hold them up against the ceiling/floor. Something like near the end of this page: http://www.saecollege.de/reference_mate ... /Walls.htm
BUT you will have to figure out the load weight of your existing ceiling/floor joists before you make any plan. Green Glue although expensive can make 2 layers of drywall almost equal to 4 layers, and makes good cents on ceilings where load is critical. I keep on refering in posts to Rod's Book in the stickies.... he has pages dedicated to this exact ceiling construction and how to do it correctly almost step by step.
Yeah, that's alot of it; I don't have the luxury of the vertical space. Where is it code that ceiling height for basements has to be 7 feet? I think that would be for 'living' spaces, no? I'm just wondering because we have a part of the basement where the ceiling height (height from basement floor to above floor joists) is less than 6'6".Another factor with ceiling is if you have the height to use seperate inner room joists for the inner leaf of ceiling. From you pic I presume you have... again span/weight is important... wait ... no you don't at 7'3" slab to joist. Code for room height is 7'. Hmmm, I'm gonna stop on this topic for now. :roll:
I agree that my concrete wall COULD be my outer leaf; it very easily could be the best sound-blocking item I got going for me! It's too bad that I don't really need to block direct sound through the concrete (walls or floor) since there is nothing behind them except earth. But it might block alot of indirect path-ing. An issue I have with the concrete walls is that there's a space of 3.5 inches between top of the concrete wall and the above floor joists -- this area might be difficult to get a good seal. It may also be hard to get a good seal between the outer leaf sheet-rock walls and the concrete. However, it's well worth looking into. Those were really the only reasons that I wanted to avoid directly using the concrete wall.Your Concrete wall should (is) your outer leaf. ... Your right on not needing the floated sub floor, expencive and easy to screw up.
I have no real plans to use the slot wall or inside-out wall design, unless it somehow could be adapted for ceiling use in my situation -- to save vertical height. But if the isolation is not too good, and the construction is more complicated, then it might be best avoided. More mass and/or more air space = more isolation. But there are other factors involved. For instance, different densities seem to have an effect, even if the total mass of leaf remains the same (the effects appear to be related to specific frequency ranges). And as I was saying above, air spaces depend on not just how thick they are, but also on other things like how well they are sealed. This is really quite apparent when one thinks of speaker cabinet designs (particularly dealing with low-frequency or bass ranges); when a cabinet is sealed, the throw of the bass driver is restricted somewhat, but when it is vented the driver is free to move air in and out of the space behind it (sometimes this can even cause a driver to destroy itself -- by travelling too far back and forth); it could even end up cancelling sound waves if any phasing inversely aligns. This almost HAS to have an effect on any of the air spaces of any of the leaves of a studio wall. In fact, we are constantly told that the leaves of a studio wall have to be sealed very very well, and that even small leaks can greatly compromise sound isolation (sound pressure tends to take the easiest path) Why then, wouldn't the fact that a 'third' leaf NOT being sealed or touching AT ALL have an effect on sound transmission? It could even be conceivable that it might largely mitigate the proximity (closeness) of the wall. What we really need to truly answer this question is results of controlled studies that vary some parameters, while keeping others the same -- or in the very least see a paper or two written by acoustical engineers or physicists, addressing this and explaining what the effects should be. Anything short of that would be speculation (although construction experience in similar situations might account for something). PICTURE NOTE: The term 'outside' refers to the rest of the air of the basement; there is NO dead air space; in a sense, the quasi-third leaf is 'ported', allowing high pressure pulses that make it through the 2nd (outer) leaf to dissipate to the entire air of the whole 'outside' basement -- that's a pretty damn big 'spring'. Does the fairly close proximity of the 2nd (outer) leaf override any benefits of this free flowing of air? *** UPDATE: I no longer plan to do the walls and ceiling as pictured below for several reason, not the least of which is the 'third-leaf' effects; see later posts ***The resontor wall and inside out wall in Kendales post from John. ...... Sound isolation is less with a inside out wall, although valuable space will be gained if using a slot wall inside the inside out wall. .... a slot wall still creates triple leaf effect which must be taken into consideration. .... BUT sometimes tripple leaf can't be avoided so it seems studio builders do there best to work around it. And remember more mass or more air = more isolation.
Check with your local building department. Note that they'll probably consider what you're doing to be converting your basement into living space (i.e., "habitable area"), so you will probably be held to those standards. There are exceptions... A certain percentage may be allowed to be lower than 7 feet. I've also sometimes heard 7' 6" is required. Again, check with your local building department. There are many sets of building codes and many versions of those codes, so it all depends on which one your municipality has adopted. --Keith :mrgreen:Where is it code that ceiling height for basements has to be 7 feet? I think that would be for 'living' spaces, no?
Hi
Well I've pretty much resolved that the concrete wall WILL be the outer leaf.
It's AT LEAST 12 inches thick of poured concrete (might even be 13 or 14 inches), with nothing but earth behind it for a minimum of 2/3 the height of the wall.
So the sound-stopping power should be better than any other member in the system.
It might even be true that a 2-leaf wall is not needed on the walls of the studio bordering the concrete (not very sure on that one).
Regarding the above floor joists and flooring:
I'm not convinced (yet) that they should be incorporated AS part of the outer leaf of the ceiling.
However, I have attached a pic showing what I'm supposing it would look like to have the above floor (and concrete wall) AS outer leaves.
There ARE some definitely known good points though.
It would:
1.) allow taller final ceiling
2.) reduce material costs
3.) reduce labor time
The big question remains whether sound control would be better with the floor incorporated into the outer leaf, or have it remain as an isolated quasi-leaf.
The potential 'mitigating' factors:
1.) loss of one isolation from a solid connection
2.) loss of free moving air between the outer leaf and the quasi-third leaf.
I'm fairly convinced that this is not a matter of simply removing a TRUE third leaf, for the reasons I have outlined in the previous post.
So, whether the loss of the free-flowing air space, and the loss of a solid connection isolation balances out against a loss of a quasi-third leaf is still pretty questionable in my mind.
Remember, this 'third' leaf is NOT sealing-in a dead air space -- it allows free flow of air around it (where any low frequency pulses might escape and dissipate into the larger part of the basement before transferring any energy to the above floor and joists?); this factor alone likely adds for some level of effect.
One other thing that I haven't really figured:
How would I then attach the top plate of the outer leaf?
Is it to be attached right to the above floor joists? (if so, then that would be a GAIN of a solid connection between the outer leaf of the studio wall and the upper floor! perhaps that's okay, but if there is still some energy vibrating in the outer leaf, then it would be transferred by conduction to the upper floor)
Maybe I could put something between the top plate and the joists that maintains the air seal between the leaves, but reduces transmission of vibrations?
thanx again,
K
In my project, my roof is considered a third leaf -- even though the attic is vented and there is a lot of air in it and the distance between my "middle leaf" and the roof is between a few inches (where it meets the east wall) and about eight feet. However, Steve and I determined that these factors mitigated the third leaf effect, but did not totally eliminate it. :roll:
I totally get what you're saying about "true" third leaves... And I think we can all agree that a "true" sealed three leaf situation is a bad thing. What I believe you're trying to nail down is how much (if at all) a compromised third leaf (in terms of venting) would affect isolation, and I believe the answer to that would be that "it depends." :roll:
The IRC has done a lot of tests on many wall configurations, but I don't know of any official studies that get into these "untrue" third leaf situations... :roll: ...That's not to say that there aren't any, just that I'm not familiar with them if they exist.
I recall hearing that Paul Woodlock did some experiments with a door, moving it around a room to see how the existence of the panel affected isolation, and I recall the outcomes raised a lot of eyebrows in in terms of the negative effects it had... Not exactly bullet-proof lab test data, but perhaps interesting and noteworthy nonetheless.
Here's an interesting thread that Rod posted to over a year ago on the subject of third leaf situations. Check it out.
Funny... When I reread that post for the umpteenth time, I'm really starting to wonder now if my roof doesn't count as a third leaf... :roll: ...Man, this stuff gets complicated, doesn't it? :? :lol:)
Thanx Sharward:
I'm so glad that I feel understood now!
You've defined my ideas pretty much on the nail head.
Certainly we all must realize that, unless there is NOTHING between the outer (2nd) leaf and the outdoor world, ALL further barriers can -- in some way -- be considered 'quasi-leafs' if they don't create a sealed air space.
It would seem to me that very few studios are 'stand-alone' structures, that is, they are most usually housed within some other building.
But you can't get a double-wall effect within the building if you believe all the other, outer walls of the main building are REALLY true extra leaves that should be included in your leaf 'count'.
I mean, take the example of a HUGE cube-shaped room (isolated from the outdoor world) that has a much smaller studio-room in the dead center of it, somehow suspended so that there is an equal amount of air space above, below, and to all sides of it.
(assume the HUGE room is 100' x 100' x 100', and the studio-room is 10' x 10' x 10'; that would leave about 90 feet of air space between all faces of the studio-room and the HUGE room).
Now the studio room builders might say: "We can't make a double-leaf wall for the studio-room since that would constitute a 3-leaf system, because there is already a leaf in the HUGE room surrounding it!"
But we all 'know', almost intuitively, that if the builders make the studio-room single-leaf (and count the HUGE room leaf as the outer 2nd leaf), there would be much more sound transmission TO the HUGE room than if they 'ignored' the leaf of the HUGE room and made the studio-room double-leaf.
So, if we are just on the outside of the HUGE room, then a single leaf for the studio-room will complete a 2-leaf system; sound transmission to the outdoors might be quite low.
But, if we are in the HUGE room, then all that's between us and the inside of the studio-room is a single-leaf; sound transmission to the HUGE room would almost certainly be higher.
THE POINT?
If we need to block sound to the rest of a larger building that surrounds (or partially surrounds) the studio-room, then we HAVE to (to some extent) ignore some walls of the larger building when counting leaves.
This might be especially so if any of them are not 'true' leaves.
In my project, my roof is considered a third leaf -- even though the attic is vented and there is a lot of air in it and the distance between my "middle leaf" and the roof is between a few inches (where it meets the east wall) and about eight feet. However, Steve and I determined that these factors mitigated the third leaf effect, but did not totally eliminate it. :roll: I totally get what you're saying about "true" third leaves... And I think we can all agree that a "true" sealed three leaf situation is a bad thing. What I believe you're trying to nail down is how much (if at all) a compromised third leaf (in terms of venting) would affect isolation, and I believe the answer to that would be that "it depends." :roll:
Regarding 3 leaf issues, I think Steve (Knightfly) has suggested the best method of testing by ear 3 leaf effects, he wrote this on my thread:
Note :!: Steve referenced a hollow concrete block wall which is two leaf (well mostly 2 leaf). I do plan to try this test at some point when the rest my to-do list calms down. I have previously thought about 3 & 4 leaf effect created from other walls and ceilings in a building, and I understand your thoughts... Luftweg, even though I am not as inclined as you to question the "proven (suggested) isolation techniques", I do admire you passion shown from your writing and number of posts. :D Ceiling height and many other things you need to know can be found in your local building code. For Florida I can find everything online. :D I found this for your local building code: http://www.mass.gov/bbrs/newcode.htm Warning: that should be painful documents to sort through, mine was. :roll: Marc :twisted:Any weakening of the isolation due to resonant traps will always be a 2-way street. For a classic example of this effect, put a loud boombox in another room, separated from you by concrete block (hollow) - Hopefully this room has a door for more isolation from the room YOU are in - pick up a 4x4 foot section of plywood or gypsum, hold it in front of you like you're gonna hang a picture on the intervening wall, and slowly walk toward this wall with the board in front of you - note which frequencies change in loudness as you get closer, right up til you actually TOUCH the block wall with the 4x4 board. Note that the changes did NOT need a SEALED trap, only the air between the board and the wall... Steve
Hey thanx! I was just looking for that.... Yeah, it seems the min height is 7 feet for a basement. Although, I haven't found anything that deals with older construction waivers. Maybe if the house is so old, then some rules can be bent.... In the area I live, you wouldn't believe some of the real old houses and the many short basements there are that are finished with short ceilings (way lower than what I would plan) -- and for years that way. There's gotta be something, because otherwise there'd be alot of houses that would be in violation it would seem. In any case, I would be able to do the between joist sheet-rock deal... Have to figure how much weight 2 x 8 live floors can take however, and that may be a limiting factor.... btw, I had seen that link to an old thread where Rod addresses the very same issue (quasi-third-leaf) -- and it seemed to concur with my thoughts! thanx, K... Luftweg, even though I am not as inclined as you to question the "proven (suggested) isolation techniques", I do admire you passion shown from your writing and number of posts. :D Ceiling height and many other things you need to know can be found in your local building code. For Florida I can find everything online. :D I found this for your local building code: http://www.mass.gov/bbrs/newcode.htm Marc :twisted:
YES a lot of houses are in violation either becuase they were built or work was done before a new code OR because new work was done without a permit. I want to rip my hair out sometimes when it comes to my own house built in 1964, there are so many things not built to today's code, which I am slowly correcting where I can.alot of houses that would be in violation it would seem
A general comment, not a fact I know: it seems most new work has to comply with new code in most places. The only exception I can think of is when it comes to keeping a building historically correct, but even with that I'm guessing. MarcAlthough, I haven't found anything that deals with older construction waivers. Maybe if the house is so old, then some rules can be bent....
Bingo. When codes evolve, existing structures built to older codes do not become noncompliant -- they become, in effect, grandfathered. Typically code evolation applies to new work. There are funny exceptions though... For example, in my town (and, for all I know, throughout California, or perhaps even throughout much of the US), any residential building permit requires that all sleeping areas in the home be equipped with smoke detectors (battery operated are OK). One cannot get a final signoff without them, even if the work has nothing to do with the bedrooms. Also, some city or county governing bodies choose to amend the codes, either upwards or downwards, based on local conditions. This is why it is always necessary to consult your local building department, because you never know if that thing you want to do that's legal everywhere else isn't allowed in your town -- or vice versa. 8) --Keith :mrgreen:YES a lot of houses are in violation either becuase they were built or work was done before a new code OR because new work was done without a permit.alot of houses that would be in violation it would seem
bump for Knightfly.... thanx, K
Luftweg,
The drawing that you posted - where you have the 3 leaf system (and yes it is a 3 leaf system - even if it has the ability to breathe into other areas of the basement - this due to the fact that the air will still act as a spring..... but let's not even bother with that - because your design introduces other problems - code violations - that - once you solve them - will stop that air flow you seem to think helps you.
Wherever a wall meets a ceiling - it is required that you install a fire stop - this because allowing a fire to climb into (and above) floor assemblies (or attics) creates a chimney effect - feeding the fire instead of starving it.
Your detail "leaf joist cross-section 2a.jpg" creates this code violation in both ceiling sections.
This is the code requirement you have to abide by:
I believe you said you have the book - look at the details in chapter 10 that show you where these firestops are required. On to the question about member size - if your existing joists are capable of the load - why not just use 2x4's and support them in the intermediate spans with isolation hangers (see detail 4.25a in the book). Then you don't have to concern yourself with sistering joists - or trying to invent some sort of quasi laminate menbers that you'll need engineering (to prove that they will work) for the building official. Sincerely, Rod720.6.2 Connections between horizontal and vertical spaces: Firestopping shall be installed at all interconnections between vertical and horizontal spaces such as occur at soffits over cabinets, drop ceilings, cove ceilings and similar locations.
I had seen in Sharward's studio thread (he is referring to a Canadian source): "These findings indicate that, from an acoustics perspective, the best way of satisfying the code requirement for fire stopping is to use a double-stud wall with sufficient insulation so that the width of the air space in the wall is 25 mm or less. This approach does not reduce the effectiveness of the sound isolation of the wall assembly, and can actually improve it if the wall cavity is less than full to begin with. " Is this true? Does blocking the spaces with fiberglass 'take care' of firestopping? (I guess this is a cue to contact the local building codes?) I found this on the Mass. codes: 720.2 Firestopping materials: All firestopping shall consist of approved noncombustible materials securely fastened in place. Firestops of approved noncombustible materials or of materials of two thicknesses of one-inch lumber with broken lap-joint, or one thickness of 23/32-inch wood structural panel with joints backed by 23/32-inch wood structural panel, or of two-inch lumber installed with tight joints, shall be installed in open spaces of wood framing. Gotta figure this one out.... Might I have to use a single, wide top plate over both leaves of the wall? Would love to totally avoid the 3rd leaf situation in the ceiling, BUT the diagram doesn't show the whole issue, which is my fear with the HEATING DUCTS, and capacity of the above floor joists (I felt that there would be a compromise in using a 'purely' 2-leaf esign, thinking it would really be like a 1.5-leaf system with respect to the ductwork).... I suppose I should see what the existing weights are (but how do do that?); there is only a bedroom above for live weight, and softwood plank underlayment with red oak hardwood flooring. I suppose I should be able to add 'some' sheetrock under the flooring....The drawing that you posted... is a 3 leaf system - even if it has the ability to breathe into other areas of the basement - this due to the fact that the air will still act as a spring..... your design introduces other problems - code violations - that - once you solve them - will stop that air flow you seem to think helps you... Wherever a wall meets a ceiling - it is required that you install a fire stop - this because allowing a fire to climb into (and above) floor assemblies (or attics) creates a chimney effect - feeding the fire instead of starving it.720.6.2 Connections between horizontal and vertical spaces: Firestopping shall be installed at all interconnections between vertical and horizontal spaces such as occur at soffits over cabinets, drop ceilings, cove ceilings and similar locations.
The book is on its way to me from Amazon....I believe you said you have the book - look at the details in chapter 10 that show you where these firestops are required.
Ah, I will look into the hangers when I get the book.... I'm seriously looking at using steel for the ceiling spans, since I have found span tables which show 4 inch deep members (of appropriate gauge and width) can run 12 feet and hold the sheet-rock. thanx, KOn to the question about member size - if your existing joists are capable of the load - why not just use 2x4's and support them in the intermediate spans with isolation hangers (see detail 4.25a in the book). Then you don't have to concern yourself with sistering joists - or trying to invent some sort of quasi laminate menbers that you'll need engineering (to prove that they will work) for the building official.
Luftweg,
I keep repeating to people the same mantra - but suppose I have to sit them down and make them breathe properly in order for them to get it.
I haven't gone through it yet with you - so I will now.
Repeat after me:
(while kneeling in the lotus position with your hands raised and the thumb with pointer finger forming an "O" - the remaining finger poined upwards).
Has sort of a soothing effect doesn't it? Bringing you closer to acoustic nirvana with every breath you take. Simply put - just because you have to violate the 2 leaf system where duct exists does not mean that you are resigned to loose it's value everywhere else. So everywhere that you can you develope the 2 leaf system - (saving a TON of money and labor in the process) and then - where you are forced - where you have no choice in the matter...... there (and only there) do you violate the 2 leaf system. This maximizes your isolation while minimizing your investment. See how easy it is? Sincerely, RodWhatever I can make perfect I will make perfect - whatever I have to live with I will Live with. Whatever I can make perfect I will make perfect - whatever I have to live with I will Live with. Whatever I can make perfect I will make perfect - whatever I have to live with I will Live with. Whatever I can make perfect I will make perfect - whatever I have to live with I will Live with.