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 Post subject: Studio Planning Stage
PostPosted: Mon Jun 12, 2017 5:14 pm 
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Location: Arcata, California USA
Hi Everyone. So much great information. I am on my second read of Rod Gervais’s book. It has been a dream of mine to have my own studio and the time has come. Here is some information and my plan. I am completely open to suggestions. I do not have my designs drafted on sketchup yet partly because I haven’t had the time to learn the program, and I was hoping for some feedback prior to meeting with my contractor who would draft the design that I can post later. Thank you - howiedrum.

Background information: I teach percussion (Western classical and Non-Western world) at our State University and I have a six-piece Afro-Cuban Timba band consisting of electric bass, drum set, keyboards/guitar, steel pan, congas/timbales, and bongos/various other percussion. I also play a fair amount of samba percussion instruments from large surdos to small tamborims and much more. I occasionally teach groups of drummers and drum set in addition to my university job. I live with my wife and eleven year old son in our three bedrooom 1800 sq. ft home. I mostly practice at the university, when I can fit it in. If I can build a soundproof detached space, I know I will practice more, and be able to teach both private and group lessons. Plus my band can rehearse there if needed. By the way, my wife has very sensitive hearing and my practicing often drives her crazy. She loves working outside, maintaining her gardens and fruit trees, so soundproofing is essential to keeping the peace and staying married. My son is playing drum kit, so I can see him using the studio more as he gets older.

Location: Northern California, Humboldt County, 6 miles east of Pacific Ocean, 270 miles north of San Francisco -USA

Rural. 2/3 of an acre parcel. I have a corner lot. The “main” road borders one side and the road adjacent to it is where we turn to get into our driveway. Both are pretty quiet. The location of the studio would be about 60 ft. from our house and main road, and about 25 ft. from my closest neighbor’s house, but only 6 ft. from the fence separating our properties.

Estimated Studio DB & TL Levels: The band peaked at about 90db. A drum class I taught at our local elementary school gym peaked at 108db. So I would assume 100db. The lowest frequencies would come from the electric bass, kick drum, and floor tom.

Noise Issues: Typical neighborhood noises around 60 db. However, our volunteer fire station is about 200 ft. away with a siren that blows whenever there is a need. Not very often. Siren measured 90 db at our house. Otherwise normal stuff like cars, motorcycles (occasionally), barking dogs and geese, riding mowers, and weed whackers.

Weather: It is pretty temperate all year long here. Average low of 41 degrees Fahrenheit and high of 64 degrees Fahrenheit. Record low was 20 degrees and record high was 87 degrees. Rains on average 45 inches per year. Rarely snows.

Goals of project:
To make the most sound-proof and energy-efficient room/building possible on a reasonable budget. The space would be mainly for practicing/rehearsing, teaching individual and group lessons, and recording occasionally. I envision an open one-room space set up for band rehearsals with a PA, cabinets and shelving for percussion instruments, desk for computer and monitor speakers.

Project Status: I met with one contractor friend of mine and we mainly discussed the mass-air-mass concept and drew some pictures of room within room ideas. I am planning on meeting with another contractor friend who has done a number of ICF buildings. His company will work on a design, but I am not sure if they will actually have time do anything other than the ICF. So I am just in the beginning planning stages trying to get a design I can furnish to this and other forums for feedback. My goal would be to have a studio done in one year from now.

Project Description:
Build room within a room from scratch. ICF construction for shell.
• Studio Dimensions 12’ height x 19’ width x 26’ length. I got a positive reading from BBC calculator. Shell would be larger by 18 inches all around and 4’ attic. My contractor suggested 10’ walls and my wife is worried about the building being too tall. For my application of mainly rehearsal studio, would lowering the ceiling to 10’ and adjust to 18.5” width with the same 26’ length be compromising the sound too much? With this lower wall height, would a vaulted ceiling help with room modes?
• Floor – Monolithic concrete slab with radiant heating.
• Walls - From outside to inside would be siding over a 6” core ICF. Then a 2” air gap followed by a 2x4 framed wall o.c 24 filled with R13 insulation, and two layers of 5/8 drywall, the first one screwed in, and the second green glued on top of it. Total wall thickness would be 18 inches. All measures would be taken to isolate the inner wall from the shell.
• Roof/Ceiling - The roof would be vaulted or tent like with plywood sheathing and shingles resting on the ICF walls. The studio ceiling would be flat (or possibly vaulted if wall height is 10’), using joists/trusses (not sure of correct term) resting on the 2x4 studio walls with 2 layers of 5/8 drywall, then insulation, 1B-1 clips with hat channel and 2 more layers of 5/8 drywall on the truss bottoms. This allows for a vented attic and the studio ceiling would be isolated from the shell roof.
• I would attach a mud room entry (it rains a lot here) around 8’x8’x8’ with a small sink, counter, and small refrigerator, leading to a super door for entrance into the studio.
• HVAC – Not sure. Will discuss with contractor or local HVAC company. Mostly I will be alone in studio, but I need to have plan for band rehearsals and occasional class. So I am thinking of 8 people max in room at one time. I won’t have a lot of heat producing gear. Perhaps that will change over time though. Definitely separate systems with heat from radiant floor. The attic dimensions would be 22’ x 29’ x 4’ (unless I vault the studio ceiling, which would reduce the gap between shell roof and studio ceiling). I believe I could use insulated flexible ducting with bends and s-shapes in attic and then drop intake and exhaust through ceiling. How would I isolate the ducts going through ceiling? Or is it better to build a decoupled soffit in studio room? Any advice? According to ASHRAE journal, Arcata, the closest city has 0.1 + 0.0 tons-hours per scfm per year. I think that means I don’t need much in dehumidification and cooling. Again fuzzy on this.
• Electricity – I will follow Rod’s and others’ suggestions and have lights and non-gear electricity on a separate circuit than the outlets that amps etc. would be plugged into. I will wire from above and down walls for lighting circuit and wire from floor for gear to keep them perpendicular and not parallel.

Known Construction Challenges:
Not much. The land would need to be prepared for the slab. Our property naturally slopes towards my neighbors property, so we don’t get much standing water, even with all the rain we have. That said, I would rely on my contractor’s advice. If need be we could put a French drain in. I have about eight trees some of which are dying, so they will need to be cut down. Finally, my wife works at home. She has a schoolroom she teaches in, so finding an appropriate time to do the construction so it does not interfere with her classes poses another challenge.

Research:
I have Rod's book, and I've spoke a few times with John Hile of soundproofing.com. He sent me some nice sims for ventilation, wall & ceiling construction, and more. I have been reading posts here at John Sayers' and at recording.org., and Gearslutz forums, all of which I am now a member.


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PostPosted: Tue Jun 13, 2017 4:35 am 
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Hi. Please read the forum rules for posting (click here). You seem to be missing a couple of things! :)

Quote:
to meeting with my contractor who would draft the design
Has your contractor also read Rod's book? As well as "Master Handbook of Acoustics" by F. Alton Everest? Does he have a solid understanding of studio design principles? Does he understand Mass Law and MSM resonance? If you have to answer "no" to any of those, then he's not the right guy to be designing your studio! You are.

Quote:
The band peaked at about 90db.
Nope. It didn't. Either you measured that incorrectly, or you have the quietest band on the West coast! By "band" I assume you mean a typical contemporary rock band, with acoustic drums, bass guitar, electric guitar, keyboards, perhaps other acoustic percussion, perhaps acoustic guitar, and vocals? If you managed to play at only 90 dB and sounded great, then you probably broke some type of record!

I'm betting that you did not set your meter to "C" weighting and "Slow" response.

What meter did you use?

Quote:
A drum class I taught at our local elementary school gym peaked at 108db.
Ditto. That's quiet, for drumming. Maybe soft jazz would get you that, but a typical heavy rock band would be ten times louder. A typical drummer playing reasonably hard on a typical kit, can easily put out 118 dBC. Put double peddles, extra cymbals, give him hard sticks and tell him to beat the hell out of it, and he'll be able to exceed 120 dBC.

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So I would assume 100db. The lowest frequencies would come from the electric bass, kick drum, and floor tom.
... as well as the electric guitar, and the keyboard. The lowest notes on the electric guitar are about the same as the typical tuning of a kick drum. Keyboards go lower.

Quote:
Typical neighborhood noises around 60 db.
That's loud! Have you looked around the neighborhood to see what's causing that? It's not a big deal for your studio, of course, and actually works in your favor, since a high level of ambient noise will mask some of the noise coming from your studio, but it's still pretty high. I just walked out in my front yard and took a reading: I was getting around 55 dBC, and I live one block away from a fairly busy intersection between two main roads. It was just before lunch time when I took that measurement (12:45), so average traffic.

Quote:
To make the most sound-proof
Please define what you mean by "sound-proof". You've mentioned how loud you think you are (although your numbers don't seem to be realistic), and you've mentioned some numbers regarding ambient levels, but you haven't said how many decibels of isolation you are shooting for.

Quote:
and energy-efficient room/building possible on a reasonable budget.
The studio itself will be energy efficient: It will have two "leaves" of high mass, each sealed totally air-tight, with thick acoustic insulation in the cavity between. So lots of thermal mass, good thermal insulation, and excellent blocking of air infiltration. Energy efficiency will depend pretty much entirely on the HVAC system you choose (EER value), and your decision on whether or not to use an ERV or HRV unit, in addition to the AHU.

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His company will work on a design,
Does the company have extensive experience in STUDIO design? Can they introduce you to other customers for whom they have designed studios? Will they arrange visits to those studios, so you can experience for yourself how well they were designed?

Experience in designing houses, shops, offices, schools, etc. does not count here. That's of very little use at all for designing a studio, since many of the concepts are completely different. Only proven experience in designing studios counts here.

Quote:
My goal would be to have a studio done in one year from now.
Yes! :thu: That's a realistic goal! Thank you! So very often we get new members joining up here, saying things like "I need to start building tomorrow, and it must be finished by next week". Absolutely nuts! Your estimate is very reasonable, and very realistic. I design studios all the time, and it normally takes me a couple of months to get from a blank screen to a full, complete design that the customer can then hand over to the contractor for a quote. In your case, you will need more months to learn acoustic design, building design, and SketchUp, plus extra time on the design itself, since this is your first time doing that. Six to eight months is a reasonable estimate for all of that, then about four months for your contractor to actually build the place. That's realistic.

Quote:
Build room within a room from scratch. ICF construction for shell.
"Shell" refers to outer-leaf, I imagine?

Quote:
• Studio Dimensions 12’ height x 19’ width x 26’ length. I got a positive reading from BBC calculator.
You are talking about a rehearsal room/tracking room, not a control room, so room ratios are not really an issue. Yes, it's still good to stay away from terrible ratios, but that's all you need to do. There's no need to look for a good ratio for a live room: that only applies to control rooms, which require neutral acoustics.

Quote:
Shell would be larger by 18 inches all around
Why? Why did you choose that number? How much isolation will it give you, in decibels? What is the lowest frequency that will isolate?

Quote:
and 4’ attic.
Why? What's the attic for? Is that going to be a sealed, unvented roof? If so, then you can't use the attic for storage, since it would be part of your MSM cavity. And if it is NOT an unvented, sealed roof, why do you want to make that into an attic?

Quote:
My contractor suggested 10’ walls and my wife is worried about the building being too tall.
Then excavate! If you want good ceiling height but cannot have a high building, then go down, instead of up.

Quote:
For my application of mainly rehearsal studio, would lowering the ceiling to 10’
If your outer-leaf WALL height is 10 feet, then your inner-leaf ceiling height will be considerably less. What is your plan for the roof trusses, and for the ceiling construction? Considering that you are planning to build very massive walls, I assume that you have a plan for equally massive roof? Are we talking a flat concrete roof here? Green roof? Something else?

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Then a 2” air gap followed by a 2x4 framed wall o.c 24 filled with R13 insulation,
Why? Why did you chose a 2" gap? And why did you choose "R13" insulation, without specifying the acoustic properties? "R13" is meaningless for acoustics, and the purpose of that insulation is purely acoustic. It serves as the damper on our MSM resonant system. Using the wrong type of insulation could cost you as much as 16 dB of isolation.

Not all types of thermal insulation are usable for acoustics. However, all types of acoustic insulation will also have good thermal properties. So it is the acoustic properties that take precedence here. I'm surprised that your contractor did not tell you about this. That indicates that he probably has no idea about acoustics, and therefor should not be designing your place.

Quote:
and two layers of 5/8 drywall, the first one screwed in, and the second green glued on top of it.
That is illegal, does not meet building code, is unsafe, and does not comply with the manufacturer's instructions. If you did that on the ceiling, you'd probably end up killing yourself, or at least causing yourself serious injury. Green Glue is NOT glue: it cannot be used as adhesive! It never dries, and that is the entire point: Green Glue is a visco-elastic polymer that is not intended, in any manner, to join two surfaces together. On the contrary, it is specifically designed to keep the two surfaces apart! It creates a CLD (Constrained Layer Damping) interface between the two surfaces, in order to damp certain acoustic resonances that would otherwise occur.

If this was the suggestion of your contractor, then you should fire him immediately and look for another contractor who would not be telling you to do illegal and dangerous things, grossly misusing building products in ways that not only defy the manufacturer's instructions, but are also just plain stupid!

Quote:
All measures would be taken to isolate the inner wall from the shell.
Such as...?

Quote:
• Roof/Ceiling - The roof would be vaulted or tent like
What exactly are we talking about here? Shed roof? Gabled roof? Gambrel? Cathedral? Dual pitch? Hip? Mansard? Clerestory? Barrel? Catenary? There's many different types of vaulted roof that could fit your description.

Quote:
with plywood sheathing and shingles resting on the ICF wall
Vented or unvented? I already asked this before, but it's an important point.

Quote:
resting on the 2x4 studio walls with 2 layers of 5/8 drywall, then insulation, 1B-1 clips with hat channel and 2 more layers of 5/8 drywall
Ummm.... don't look now, but you just described a three-leaf ceiling with poor low frequency isolation.... And we haven't yet gotten to the inner-leaf!

Quote:
leading to a super door for entrance into the studio.
Why did you choose a superdoor, rather than a pair of conventional doors, back to back?

Quote:
• HVAC – Not sure. Will discuss with contractor or local HVAC company.
Hopefully not the same contractor who wanted you to used building materials in an unsafe and illegal manner! Hopefully it will be a contractor who has actual proven experience designing HVAC systems for real studios... Ask to see examples of silencer boxes that he has designed. Ask what the highest air velocity will be at the registers...

Quote:
So I am thinking of 8 people max in room at one time. I won’t have a lot of heat producing gear.
8 people playing hard could be producing as much body heat as a couple of large space heaters. Their gear could add up to a couple more. Then there's the issue of their latent heat load, in addition to the sensible heat load, which you'll have tot take into account along with the typical relative humidity of your climate...

Quote:
Definitely separate systems with heat from radiant floor.
Are you aware that radiant floor heating is nowhere near as efficient as a good HVAC system? You can easily find HVAC systems with EER ratings well over ten these days. An electric radiant floor will have an EER rating of 1, In other words, your radiant floor will consume ten times as much electrical power to produce the same amount of heat as the AHU does. In addition, the radiant heat element has to heat up the entire slab of concrete before you get any noticeable heat in the room, whereas the HVAC system can have the room toasty in minutes.

Quote:
I believe I could use insulated flexible ducting with bends and s-shapes in attic and then drop intake and exhaust through ceiling.
With studio design, you should NEVER based anything on "belief". Belief is wonderful thing for your spiritual life, but when it comes to studio design it's probably better to use actual empirical rules and mathematical calculations to determine if something will work or not.

Quote:
How would I isolate the ducts going through ceiling?
With silencer boxes. You would need to know the air flow rate (volume per unit time) and the air flow velocity (distance per unit time) and the cross sectional area of the ducts and/or registers on the ends of the box, as well as the required insertion loss, and the maximum allowable increase in static pressure, along with the required isolation of the studio as a whole (in decibels), in order to design your silencer boxes. Assuming that you want high isolation (which seems to be the case, based on what you have said so far), you will need two silencers on each duct: one where it penetrates the outer leaf, and another where it penetrates the inner leaf. So four silencer sin total (one pair on the supply duct, another pair on the exhaust duct).

Quote:
Or is it better to build a decoupled soffit in studio room?
For what purpose? I'm not understanding that comment.

Quote:
I think that means I don’t need much in dehumidification and cooling.
Your total cooling is calculated based on your sensible heat load, plus the latent heat load. You calculate the sensible heat load by adding up the energy consumption of each and every device in your room (all your equipment, your computer, hard disks, monitors, amps, speakers, lights, chargers, and everything else that consumes electricity), and getting the total in kilowatts, as well as the heat produced by the number of human bodies in the room (living bodies, not dead ones!), based on the physical activity they are engaged in, plus any input from external sources, such as sunlight, heat form the ground, nearby rivers of molten lava, etc. The total of all of that is your sensible heat load. So you would have to take into account 8 human bodies doing medium work (jamming), plus the power consumed by all of their gear, and the power consumed by all of your gear, and the lights, and the heat coming in through the roof, walls, windows, doors, and floor.

Latent heat is the amount of energy that the HVAC system needs to dispose of when the water vapor in the air changes phase to liquid water, as it condenses on the cooling coils of the AHU. You figure that out by looking at the normal relative humidity of the air in your climate, plus the amount of humidity added by 8 sweating bodies that are also exhaling water vapor in every breath, and comparing that to the relative humidity level that you need to maintain inside your studio at all times, which is 40%. Since the relative humidity in the room will be higher than 40%, the HVAC system will need to remove the energy that is dumped by the air as the excess water changes phase from gas to liquid. That's your latent heat load. In other words, it's the amount of energy that is removed from the air just to cause the moisture to condense, before any cooling of the air actually happens. If you live in a very humid climate, and have very sweaty musicians, then you'll need to take into account a high latent heat load. If you live in a dry climate and the musicians are all sleeping on the floor, then your latent heat load will be much lower.

You need to get this right! If you calculate wrong here, then the HVAC system won't be able to cool the air enough, and it will get very warm and muggy in there, even when they HVAC is running full bore. Or if you get it wrong the other way, the humidity will be too low in the room, causing the instruments and some mics) to change tone, de-tune, and perhaps even suffer damage in extreme cases over long periods of time.

Don't guess or just "believe" that it will work out....

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Not much. The land would need to be prepared for the slab.
Is permafrost an issue? Ground heaving? What is your soil type?

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That said, I would rely on my contractor’s advice.
No. When designing the foundations for a building, you do NOT need your contractor's advise! What you need is a structural engineer, who has experience in soil properties, and foundations. He is the ONLY person who is qualified to do that. He will take a look at your soil (perhaps even conduct an analysis on it), and take a look at the load you plan to place on it, he will consider the slope, water issues, possible seismic issues, possible climate issues, then he will design the foundations to safely support your building load on your soil. Anything else is guesswork, and is just plain silly, if not illegal. Designing foundations is serious business. Get it wrong and the building will sink, tilt, heave, or even collapse. Get it wrong he other way, and you spent a lot more money than you needed too...

Quote:
She has a schoolroom she teaches in, so finding an appropriate time to do the construction so it does not interfere with her classes poses another challenge.
Realistically, the construction is going to take many weeks, probably months. If the contractor can only work on certain days of the week, and only during certain times, then be prepared to pay a LOT more for his services. He will greatly in crease the price due to the need to transport his workmen and tools far more often than is necessary. He will probably bill you for the extra travel time as actual work hours as well, and rightly so. I would suggest adding 10% to 20% to your budget, to compensate for this.

Overall, it seem to me that you are listening to the wrong people, and assigning tasks to the wrong people. Firstly, you should NOT allow your contractor to do any design work, any more than you wold allow your structural engineer to tune your drum kit, or allow your bass guitarist to pour the slab. You need to either learn how to design the studio yourself, of hire a studio designer to o that (I'd suggest that you hire John, of course!). Then, once you have the full design in hand, you can take it to your structural engineer for him to check over ans make sure that it is safe and meets code. Then you take it to your architect, who will prepare the drawings and present them to the local authorities for approval, so you can get your permits. And only once you have all that lined up, then you go to SEVERAL contractors (not just one) and get them all to bid on the project. Then you choose the bid that best fits your needs (NOT the cheapest bid). Then you sign the contract, and the contractor starts building.

That's the usual way of building a studio. You seem to be starting backwards, by first choosing the contractor! He's the LAST one in the chain, not the first. And you especially do not want a contractor who tells you to do illegal, unsafe, silly things, such as trying to glue up the second layer of drywall, instead of nailing it or screwing it as required by code, and even worse, suggests using a product that is not even adhesive!

So Id' suggest that you need to go back to square one, and get your process in order: First, design. Then check the design for safety and code compliance (and modify if needed). Then get your permits. Then look for contractors.



- Stuart -

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PostPosted: Wed Jun 14, 2017 4:20 am 
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Soundman,

My apologies for not following the instructions. My first post was copied from a different forum's instructions. My bad. I couldn't find how to upload information to my profile either. Not sure why I didn't see the profile button. I appreciate that you still gave me valuable feedback. I know that was a lucky break. Thank you!

I have been reviewing the REFERENCE area and it has answered some of my questions. I will continue to review it. In the meantime I would like to add/clarify some information and respond to some of your comments. In regards to budget, I set aside $45,000 but I could go higher if necessary.

Quote:
If you have to answer "no" to any of those, then he's not the right guy to be designing your studio! You are.
I agree. I am going to design it myself and then take it to a structural engineer, then to an architect, and then I'll take bids. Good advice!

Quote:
I'm betting that you did not set your meter to "C" weighting and "Slow" response.What meter did you use?

You are right. It was set on "A" weighting. I use db Meter, an app for my iPhone. I have since changed to "C" weighting. The band peaked at 104dBC.

Quote:
how many decibels of isolation you are shooting for.
I need to get back to you on this. I will play my timbales and drum set and see the levels I get. Stay tuned.

Quote:
"Shell" refers to outer-leaf, I imagine?
Yes, it would be the exterior wall of building, made with ICF blocks filled with concrete, with siding added, exposed to the outside world. I realize that I am not really building a room within a room. I am constructing a building where the outer-leafs will be the exterior walls. The wall with the door(s) will have a 8'x8'x8' entry way addition. This addition would share one outer-leaf with the three other sides just sheathing an siding. No other mass or insulation. Basically the entry way would be a place to take off rain gear and store cases if necessary. Serve as an air lock if I understand air lock correctly.

Quote:
You are talking about a rehearsal room/tracking room, not a control room, so room ratios are not really an issue.
Thank you. I have been confused about this.

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Why 18 inches all around?
ICF with 6" core is 11.25" total width, plus 2" air gap, 2x4 frame (3.5") and 5/8 dw x2 (1.25") = 18inches. I like ICF because it appears to be cheaper, quicker, with excellent sound attenuation of 50-55 STC. I was basically trying to mimic Rod's double stud wall but use ICF for outer leaf. The added inch of air gap would give a little more isolation, but not sure if that is necessary.

Quote:
How much isolation will it give you, in decibels? What is the lowest frequency that will isolate?
Great questions. I am not sure how much isolation that would be in decibals nor what the lowest frequency it would isolate. How can I compute this? If you think it is covered in the reference area, I can search it.

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What's the attic for? Is that going to be a sealed, unvented roof?
Not really an attic. It would be a vented roof, not sealed.

Quote:
If your outer-leaf WALL height is 10 feet, then your inner-leaf ceiling height will be considerably less. What is your plan for the roof trusses, and for the ceiling construction? Considering that you are planning to build very massive walls, I assume that you have a plan for equally massive roof? Are we talking a flat concrete roof here? Green roof? Something else?
Good reason to go for higher ceiling. As you suggested I can excavate down, 5', so above ground I would be 8'. Roof trusses would rest on the ICF outer leaf. Roof would be a Gabled roof. Studio ceiling would be 2x6 kiln dried pine O.C. 12 resting on inner leaf. Mass would be layers of dry wall. I still need to compute how much mass I need to account for the lowest frequencies. The walls may be more massive than they need to be, but still cheaper than a regular double stud wall due to the ICF.

Quote:
Green Glue is NOT glue:
Oh. I didn't know that. I assumed based off of sims from soundproofing.com that it was a glue. Got it. Makes a ton of sense now. It prevents flanking. Not an adhesive.

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All measures would be taken to isolate the inner wall from the shell.
Such as...?
I mean inner leaf from outer leaf. I will document ideas based off of Rod's designs. Stay tuned for more details.

Quote:
resting on the 2x4 studio walls with 2 layers of 5/8 drywall, then insulation, 1B-1 clips with hat channel and 2 more layers of 5/8 drywall
Ummm.... don't look now, but you just described a three-leaf ceiling with poor low frequency isolation.... And we haven't yet gotten to the inner-leaf!
Are you considering the building roof to be a leaf? It has shingles over plywood and vented. Again I need to determine how much low frequency isolation I need, but I have a design from soundproofing.com. I couldn't get image uploaded. I can research this and load later.

Quote:
Why did you choose a superdoor, rather than a pair of conventional doors, back to back?
I could do either but I like the idea of using one door to enter the studio. Many of my instruments are bulky.

Quote:
Are you aware that radiant floor heating is nowhere near as efficient as a good HVAC system? You can easily find HVAC systems with EER ratings well over ten these days. An electric radiant floor will have an EER rating of 1, In other words, your radiant floor will consume ten times as much electrical power to produce the same amount of heat as the AHU does. In addition, the radiant heat element has to heat up the entire slab of concrete before you get any noticeable heat in the room, whereas the HVAC system can have the room toasty in minutes.
I was not aware of this. I am definitely not attached to a radiant floor. I will research references for more HVAC ideas. Stay tuned.

I will work on learning SketchUp so I can post a design.


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PostPosted: Mon Jun 19, 2017 11:57 am 
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Quote:
My apologies for not following the instructions. My first post was copied from a different forum's instructions. My bad. I couldn't find how to upload information to my profile either. Not sure why I didn't see the profile button. I appreciate that you still gave me valuable feedback. I know that was a lucky break. Thank you!
No problem. You are all good now!

Quote:
In regards to budget, I set aside $45,000 but I could go higher if necessary.
For a room that is 19x26 = 494 ft2, that's nearly US$ 100/ft, which is in the ballpark.

Quote:
I agree. I am going to design it myself and then take it to a structural engineer, then to an architect, and then I'll take bids. Good advice!
Smart move! You already mentioned Rod's book but I'd suggest adding another to your reading schedule: "Master Handbook of Acoustics" by F. Alton Everest (that's sort of the Bible for acoustics).

Quote:
You are right. It was set on "A" weighting. I use db Meter, an app for my iPhone. I have since changed to "C" weighting. The band peaked at 104dBC.
Unfortunately, cell phone apps are not much use for doing serious acoustic measurements. The mic is not up to the job, firstly because it is not an omni mic (which it MUST be for acoustics, for obvious reasons), and secondly because it is designed to capture voices and reject other sounds... So if you are serious about designing and building your studio properly, I'd suggest buying a proper sound level meter. They are not expensive: a good one goes for about US$ 100 or so on eBay or Amazon. Don't get one of the cheap Chinese "toys", that go for under US$ 50. No use at all.

Quote:
Yes, it would be the exterior wall of building, made with ICF blocks filled with concrete, with siding added, exposed to the outside world.
That's a pretty good outer leaf...

Quote:
I realize that I am not really building a room within a room. I am constructing a building where the outer-leafs will be the exterior walls.
That's correct: In most home studios, the outer leaf walls ARE the exterior walls of the building. You then build a single inner-leaf within that. The inner-leaf does not touch the outer leaf. I'm wondering why you don't want to do that?


Quote:
This addition would share one outer-leaf with the three other sides just sheathing an siding. No other mass or insulation. Basically the entry way would be a place to take off rain gear and store cases if necessary. Serve as an air lock if I understand air lock correctly.
Not sure I follow what you are saying: Please show that in a clear, accurate diagram, or better yet in SketchUp.

Quote:
ICF with 6" core is 11.25" total width, plus 2" air gap, 2x4 frame (3.5") and 5/8 dw x2 (1.25") = 18inches.
Hang on a sec! You said that you are NOT doing room-in-a-room, but then you just described room-in-a-room! :shock: :?: confused.... So are you going to do a proper fully-decoupled 2-leaf MSM isolation system, often called "room-in-a-room", or are you NOT going to do that, leaving just the outer leaf all by itself? Not clear at all....

Quote:
like ICF because it appears to be cheaper, quicker, with excellent sound attenuation of 50-55 STC.
Yes it is good, but stay away from judging your isolation using STC. Here's why: It is no use at all for telling you how well your studio will be isolated! STC was never meant to measure such things. Here's an excerpt from the actual ASTM test procedure (E413) that explains the use of STC.

“These single-number ratings correlate in a general way with subjective impressions of sound transmission for speech, radio, television and similar sources of noise in offices and buildings. This classification method is not appropriate for sound sources with spectra significantly different from those sources listed above. Such sources include machinery, industrial processes, bowling alleys, power transformers, musical instruments, many music systems and transportation noises such as motor vehicles, aircraft and trains. For these sources, accurate assessment of sound transmission requires a detailed analysis in frequency bands.”

It's a common misconception that you can use STC ratings to decide if a particular wall, window, door, or building material will be of any use in a studio. As you can see above, in the statement from the people who designed the STC rating system and the method for calculating it, STC is simply not applicable.

Here's how it works:

To determine the STC rating for a wall, door, window, or whatever, you start by measuring the actual transmission loss at 16 specific frequencies between 125 Hz and 4kHz. You do not measure anything above or below that range, and you do not measure anything in between those 16 points. Just those 16, and nothing else. Then you plot those 16 points on a graph, and do some fudging and nudging with the numbers and the curve, until it fits in below one of the standard STC curves. Then you read off the number of that specific curve, and that number is your STC rating. There is no relationship to real-world decibels: it is just the index number of the reference curve that is closest to your curve.

When you measure the isolation of a studio wall, you want to be sure that it is isolating ALL frequencies, across the entire spectrum from 20 Hz up to 20,000 Hz, not just 16 specific points that somebody chose 50 years ago, because he thought they were a good representation of human speech. STC does not take into account the bottom two and a half octaves of the musical spectrum (nothing below 125Hz), nor does it take into account the top two and a quarter octaves (nothing above 4k). Of the ten octaves that our hearing range covers, STC ignores five of them (or nearly five). So STC tells you nothing useful about how well a wall, door or window will work in a studio. The ONLY way to determine that, is by look at the Transmission Loss curve for it, or by estimating with a sound level meter set to "C" weighting (or even "Z"), and slow response, then measuring the levels on each side. That will give you a true indication of the number of decibels that the wall/door/window is blocking, across the full audible range.

Consider this: It is quite possible to have a door rated at STC-30 that does not provide even 20 decibels of actual isolation, and I can build you a wall rated at STC-20 that provides much better than 30 dB of isolation. There simply is no relationship between STC rating and the ability of a barrier to stop full-spectrum sound, such as music. STC was never designed for that, and cannot be used for that.

Then there's the issue of installation. You can buy a door that really does provide 40 dB of isolation, but unless you install it correctly, it will not provide that level! If you install it in a wall that provides only 20 dB, then the total isolation of that wall+door is 20 dB: isolation is only as good as the worst part. Even if you put a door rated at 90 dB in that wall, it would STILL only give you 20 dB. The total is only as good as the weakest part of the system.

So forget STC as a useful indicator, and just use the actual TL graphs to judge if a wall, door, window, floor, roof, or whatever will meet your needs.

So yes, ICF is a good way of getting decent isolation, but STC is a lousy way of measuring that!

Quote:
I was basically trying to mimic Rod's double stud wall but use ICF for outer leaf.
That's fine. And valid.

Quote:
The added inch of air gap would give a little more isolation, but not sure if that is necessary.
depends on how much you need! :)

Quote:
Great questions. I am not sure how much isolation that would be in decibals nor what the lowest frequency it would isolate. How can I compute this?
Good question! Time to put on your learning cap, and get totally confused, before it starts making some sense...

The equations for calculating total isolation of a two-leaf wall are simple:

First, for a single-leaf barrier you need the Mass Law equation:

TL = 14.5 log (M * 0.205) + 23 dB

Where: M = Surface density in kg/m2

For a two-leaf wall, you need to calculate the above for EACH leaf separately (call the results "R1" and "R2"), then you need to know the resonant frequency of the complete system, using the MSM resonance equation:

f0 = C [ (m1 + m2) / (m1 x m2 x d)]^0.5

Where:
C=constant (60 if the cavity is empty, 43 if you fill it with suitable insulation)
m1=mass of first leaf (kg/m^2)
m2=mass of second leaf (kg/m^2)
d=depth of cavity (m)

Then you use the following three equations to determine the isolation that your wall will provide for each of the three frequency ranges:

R = 20log(f (m1 + m2)) - 47 ...[for the region where f < f0]

R = R1 + R2 + 20log(f x d) - 29 ...[for the region where f0 < f < f1]

R = R1 + R2 + 6 ...[for the region where f > f1]

Where:
f0 is the resonant frequency from the MSM resonant equation,
f1 is 55/d Hz
R1 and R2 are the transmission loss numbers you calculated first, using the mass law equation

And that's it! Nothing complex. Any high school student can do that. It's just simple addition, subtraction, multiplication, division, square roots, and logarithms.

So then you will know the approximate isolation that you'll get in each of those regions, and you can compare that to the isolation you need in each of those regions. If your calculated isolation is not enough, then you'll need to add more mass, or make the air gap larger, or both, and repeat the process.

Quote:
Not really an attic. It would be a vented roof, not sealed.
OK, so you will have a vented roof, which also implies that you'll need a three-leaf ceiling. So you'll need more mass on the middle leaf, and larger air gaps than you would have had if you could have done it with just two leaves.

Quote:
Roof would be a Gabled roof.
What type of trusses? If you use scissor, or better still raised collar tie, then you could gain even more headroom up there.

Quote:
Studio ceiling would be 2x6 kiln dried pine O.C. 12 resting on inner leaf.
I don't think so! 2x6's are not going to safely span those distances with that amount of load on them. Did you actually check that with a span calculator, or span table? I would guess more like 2x10...

Quote:
Oh. I didn't know that. I assumed based off of sims from soundproofing.com that it was a glue. Got it. Makes a ton of sense now. It prevents flanking. Not an adhesive.
It's not that it prevents flanking: it damps certain types of resonance in the wall itself, including bending waves.

Quote:
Are you considering the building roof to be a leaf? It has shingles over plywood and vented.
Yes, that is a leaf. It might not have a huge effect as a third leaf, but potentially it can have some effect.

Quote:
Again I need to determine how much low frequency isolation I need, but I have a design from soundproofing.com.
I'd love to see that. Please post it here.

Quote:
I could do either but I like the idea of using one door to enter the studio. Many of my instruments are bulky.
Actually, a supedoor will probably have to be narrower than normal back-to-back doors! The superdoor is very, very heavy, so as it opens it places major bending, warping, twisting stresses on the frame, and attempts to drag it out o true. So after a while, your door will end up sagging slightly, and will bind on the jams and threshold, and your seals won't work any more, as there will be gaps. If you do it the normal way, with one door in each leaf, each of those can be lighter than a superdoor, and therefore can be wider, allowing larger items in easily, without sagging, twisting, bending or warping so much.

Quote:
I will work on learning SketchUp so I can post a design.
:thu: It's a bit quirky when you first start learning it, but when you get the basic concepts in place it's a very powerful tool. Major hint: "components" and "layers" and "scenes". Every time you make a new piece of geometry, immediately convert it into a "component". If you don't, it will "stick" to other pieces of geometry, and that will really mess you up. Also, as soon as you make it into a component, give it a name and put it in a layer. In other words, all your studs can go on a layer called "studs", all your glass on a layer called "glass", etc. Then you can create "scenes", where you have a view point you like, and can have some layers visible and other turned off. When you get used to doing that, you'll make your life much, much easier.



- Stuart -

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PostPosted: Tue Jul 04, 2017 11:07 am 
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Location: Arcata, California USA
Quote:
You already mentioned Rod's book but I'd suggest adding another to your reading schedule: "Master Handbook of Acoustics" by F. Alton Everest (that's sort of the Bible for acoustics).
Thanks. I just received it. Will be good reading for the next month or so.

Quote:
So if you are serious about designing and building your studio properly, I'd suggest buying a proper sound level meter. They are not expensive: a good one goes for about US$ 100 or so on eBay or Amazon. Don't get one of the cheap Chinese "toys", that go for under US$ 50. No use at all.
Ok. I just ordered one by America Recorder Technologies. It does both A & C weighting and slow or fast response.

Quote:
That's correct: In most home studios, the outer leaf walls ARE the exterior walls of the building. You then build a single inner-leaf within that. The inner-leaf does not touch the outer leaf. I'm wondering why you don't want to do that?
Thanks for clearing this up. This is exactly what I am doing. I second guessed myself into thinking a room within a room had a shell where the exterior leaf was not the exterior wall of the building but 4 feet or so away from the exterior wall of the building.

Quote:
like ICF because it appears to be cheaper, quicker, with excellent sound attenuation of 50-55 STC.
Yes it is good, but stay away from judging your isolation using STC.
When I wrote this, I anticipated your response. STC is not to be used to judge isolation. Understood. Thank you for your detailed explanation.

Quote:
The equations for calculating total isolation of a two-leaf wall are simple: First, for a single-leaf barrier you need the Mass Law equation:TL = 14.5 log (M * 0.205) + 23 dB Where: M = Surface density in kg/m2
How do I figure out the surface density? For the ICF exterior leaf (R-28, 6" concrete walls with Ultra EPS), each Ultra EPS panel is 1.5 lbs/ft3 [24 kg/m3]) and for the 6" concrete, I found "one cubic inch of concrete =0.039 kg/in^3 or 0.087 lb/cu in. So 6 inches = .234kg/in^3. Am I on the right track?

Quote:
OK, so you will have a vented roof, which also implies that you'll need a three-leaf ceiling. So you'll need more mass on the middle leaf, and larger air gaps than you would have had if you could have done it with just two leaves.
Can you do a two-leaf ceiling and still have proper ventilation?

Quote:
What type of trusses? If you use scissor, or better still raised collar tie, then you could gain even more headroom up there.
Originally I was thinking flat ceiling resting on inner leaf walls, but scissor or raised collar tie trusses would be great. I just not sure how to design it. I have practically zero carpentry skills/knowledge. Perhaps the answer to the question of two-leaf ceilings will clear things up for me.

Quote:
I don't think so! 2x6's are not going to safely span those distances with that amount of load on them. Did you actually check that with a span calculator, or span table? I would guess more like 2x10...
You are correct according to the span calculator I just used. I was referring to a span table I found online, but the calculator I just used confirmed your suspicions.

Quote:
I'd love to see that. Please post it here.
How do I upload/post a picture on the forum?

Quote:
Actually, a supedoor will probably have to be narrower than normal back-to-back doors! The superdoor is very, very heavy, so as it opens it places major bending, warping, twisting stresses on the frame, and attempts to drag it out o true. So after a while, your door will end up sagging slightly, and will bind on the jams and threshold, and your seals won't work any more, as there will be gaps. If you do it the normal way, with one door in each leaf, each of those can be lighter than a superdoor, and therefore can be wider, allowing larger items in easily, without sagging, twisting, bending or warping so much.
Make sense. Thank you. I will take your advice and use back-to-back doors.

Quote:
I will work on learning SketchUp so I can post a design.
:thu: It's a bit quirky when you first start learning it, but when you get the basic concepts in place it's a very powerful tool.
Thanks for the hints and encouragement. I hope to start experimenting with it soon. My Sketchup Pro trial version is about to expire. Am I correct in assuming that the free SketchUp Make will be sufficient for my design work?


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PostPosted: Fri Apr 27, 2018 4:39 pm 
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Location: Arcata, California USA
My last post was on July 3, 2017.

Recap:

1) New construction 95ft. from my neighbor’s front door, 100ft. from my home’s back door, and 150ft from my wife’s schoolroom/shop. Wife’s botanical garden is 12ft from the north wall of studio. Therefore I want a high level of isolation because gardening is her sanctuary.
2) Live Room Only. Mostly to practice drums and percussion, teach group and private percussion lessons, and rehearse my salsa band.
3) 6-piece instrumental salsa band rehearsals peaked at 118 dbc. That was with the meter only a foot from the ride cymbal. I got a reading of 113dbc about 3 feet away. But still planning for 118dbc.
4) Neighborhood noise around 55 dbc but up to 70 when cars drove by.
5) Lowest frequencies would come from the keyboard at 27.5
6) Slab foundation.
7) Vented roof (thus unavoidable triple leaf)
8. Double stud studio walls.
9) Back to back doors.

Changes I have made:

1) I have abandoned the ICF (issues with the only ICF licensed contractor in my area) in favor of wood stud construction.
2) I have added a 6ft. x 18ft x 12ft (outer leaf dimensions) kitchenette
3) Studio is now 26ft. x 18ft (outer leaf walls) x12ft (middle leaf). The inside of studio dimensions are
16'-5"x24'-5"x11'-1.75". 401sq.ft. and volume is 4,409 cu. ft.
4) Ceiling will be flat.
5) Adding a 5’x3-6” laminated glass picture window.

Attachment:
Prelim-Model-2 small.jpg


Studio Walls Current Plan:

1) Outer leaf = Hardi Panel siding, Vapor Barrier, ¾” OSB, Green Glue, ¾” OSB on 2x4 frame
2) 1 inch Gap
3) 2x4 Framed Inner leaf = Vapor barrier, ¾” OSB, Green Glue, 5/8 drywall
4) Fill entire 8-inch gap with mineral wool.

If I can get 63db of isolation, then when my band is at its loudest (118db), the outside db would be 55. That would be ideal, but I can definitely live with the outside db as high as 70 which would be 48db of isolation.

Using the Mass Law equation (can someone check my math?):

Outer leaf (not including Green Glue)
M = 22kg/m2 (3/4 OSB x2)
TL = 14.5 log (22 * 0.205) + 23 dB = 32.48db

Inner leaf (not including Green Glue)
M = 21.74kg/m2 (3/4 OSB +5/8 drywall)
TL = 14.5 log (21.74 * 0.205) + 23 dB = 32.41db

Resonant Frequency of complete system (not including Green Glue)
C=43; Depth = .234m

f0 =43 [(22 + 21.74)/ (22 x 21.74) x 0.234]^0.5
f0 = 43 [43.74/ 111.91)^0.5
f0 = 43[.3884] ^0.5
f0 = 26.8

Isolation for each of the three frequency ranges:
f0=26.8; f1=55/d = 234Hz; R1 = 32.48db; R2 = 32.41db

1) R = 20log(f (m1 + m2)) - 47 ...[for the region where f < f0].
R = 20log (26 (43.74) -47 = 60.75

2) R = R1 + R2 + 20log(f x d) - 29 ...[for the region where f0 < f < f1]
R = 32.48 + 32.41 +20log(27.5 x .234) -29 = 52
R = 32.48 + 32.41 +20log(233 x .234) -29 = 71
So my isolation is between 52-71 for frequencies between 27.5 - 234Hz. If this is correct then I am good!

3) R = R1 + R2 + 6 ...[for the region where f > f1]
R = 32.48 + 32.41 + 6
R = 70.89
So does that mean that I would get 70.89db of isolation for frequencies above 234Hz?

Did I do this right?

Vented Roof/Ceiling Plan

Please see my attached plan below. The attached plan shows three layers of mass for my middle leaf, but I am going to change that to two layers, same as walls. The attached plan is with trusses for roof. But I am going to change that to stick construction (beam and joists) so I can do an inside/out ceiling.

Attachment:
SECTION-2 small.jpg


3/4OSB and 5/8 drywall with GG in-between for both leafs. Insulation (mineral wool) between joists.

2x8 joists for framing of both leaf ceilings.

HVAC

My plan is to use a high static mini-split heat pump ducted AHU system coupled with an ERV (relative humidity is in the 90's on average throughout the year. Lots of rain in Humboldt County!)

Volume of inside of studio is 4,409 cu. ft., which is 26,454 cu. ft. per hour. Thus 441cfm.
Air Velocity: 441/300 = 1.47sq. ft. = 212sq. in.

Cooling/Heating requirements (live room only, no control room):

GEAR
Powered Speakers 1000Watts
Bass Amp 300 Watts
Guitar Amp 300 Watts
Fender Power Amplifier 350 Watts
Roland JV 880 16 Watts
IMAC Computer 41 Watts
TOTAL 2007 Watts

Lighting
400sq.ft. x2) = 800 watts

People
Met rate of 3.0 for 400 sf. = 322w per person (x6) = 1,932 watts

GRAND TOTAL 4,739 WATTS
4,739 x 3.4129 = 16,172 Btu’s/Hr. or 1.34 tons of cooling per hour

The following LG products should satisfy my needs. I'd rather have a 1.5 ton condenser, but LG's smallest is 2 ton. Is 2 ton too big?

AHU Unit - LG ARNU183BGA4 Multi VTM Ducted (High Static) 19,100 Btu/h Indoor Unit.
Attachment:
SB_MultiV_HighStaticDucted_ARNU183BGA4_10_16 small.jpg

Condensor - SB_MultiV_S_HP_ARUN024GSS4_12_17
Attachment:
SB_MultiV_S_HP_ARUN024GSS4_12_17 small.jpg

ERV - LG ERV_ARVU063ZEA2_
Attachment:
VRF_SB_DT_002_US-014B11_LGSubmittal_ERV_ARVU063ZEA2_20140320124321 small.jpg


LG AHU max airflow rate = 547cfm = 547/300 = 1.8sq.ft. = 259 sq. in.

So working backwards, the duct size at supply register could be 22x12, 18x16, 20x14, 26x10. I choose the 22x12. Adding 1" duct liner all around comes to 24"x14" duct with a Nailor 24x12" diffusor.

The silencer boxes would need to be large. The silencer would have 3 baffles inside each with the same cross sectional area of 14x24. Plus 1” duct lining added and 1.5” OSB for shell. Thus the outer dimensions of box would be 19”x 27". The space between baffles would be 14". Baffles would be 1" plus 1" duct liner = 3". So length would be (4x14) + (3x3) = 65" plus 3" OSB = 68”. So total dimensions would be 19”x 27"x68”. Plus ideally a sleeve leading to register of 42".

I can fit two in the attic leading into middle leaf, but not sure how to fit leading into inner leaf. Any ideas?

Doors (all solid wood 1-3/4 inch thick)

1) Studio back-back front doors off covered porch:
Does 42inches instead of 36 inch standard pose any problems? A wider door would help when transporting bulky items like bass drums in cases.

2) Studio back-back rear doors leading into kitchenette/bath would be 30inches wide. Any problems with that?

Would any of these doors need additional mass?

Picture Window

The 2 layers of 3/4 OSB = 5psf. and one layer of of 3/4 OSB and one layer of 5/8 drywall = 5.25psf. So to make sure I have more mass than that I will go with 3/4in. laminated glass on exterior leaf and 1/2in. laminated glass on inner leaf. In the seal I will place some bags of desiccant to protect against moisture.

Or should I go 1/2in. on exterior and 3/4in. on inner leaf? Does it matter? Any issue that I have not accounted for Green glue?

Thank you for all your help!


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PostPosted: Mon May 28, 2018 3:50 pm 
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Location: Arcata, California USA
I didn't realize that my pictures were too big. So I just resized them to 700 pixels wide and 150kb or smaller. Hopefully that is the reason I haven't received any response to my last post.

My draftsperson is waiting for the size and location of my silencer boxes before she does the final plan for submittal to the building department. I was shooting for construction to start at end of July, which requires that I submit the plan asap. So I humbly ask if you can please review my plans. I still have time to change things if necessary.

Best wishes,

Howie


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PostPosted: Mon May 28, 2018 4:10 pm 
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Location: Santiago, Chile
Quote:
1) Outer leaf = Hardi Panel siding, Vapor Barrier, ¾” OSB, Green Glue, ¾” OSB on 2x4 frame
2) 1 inch Gap
3) 2x4 Framed Inner leaf = Vapor barrier, ¾” OSB, Green Glue, 5/8 drywall
4) Fill entire 8-inch gap with mineral wool.
No no no! Never have TWO vapor barriers in a wall! That will trap moisture inside the cavity, and you'll end up with all kinds of nasty things... Only ever have ONE vapor barrier, assuming you need any at all. If you do need one, it normally goes on the side of the cavity that is warmer.

Quote:
If I can get 63db of isolation, then when my band is at its loudest (118db), the outside db would be 55. That would be ideal, but I can definitely live with the outside db as high as 70 which would be 48db of isolation.
You should be in that ball park for sure, and probably closer to the high end than the low end.
Quote:
GRAND TOTAL 4,739 WATTS
4,739 x 3.4129 = 16,172 Btu’s/Hr. or 1.34 tons of cooling per hour
You are only calculating for sensible heat load: what about your latent heat load? You say you live in a very high humidity area, so your latent heat load is likely to be higher than average. Don't forget to take that into account. At a rough guess (I didn't do the math), I'd say that your total heat load is going to be around 14,000 BTU, so you'd need a 2 ton system, at least.

Quote:
Does 42inches instead of 36 inch standard pose any problems?
As long as you can find suitable hinges to take that heavy load, and as log as you have really firm anchoring for those hinges, deep into your rough framing, and as long as you can find an automatic door closer that can handle that weight, and as long as you use adjustable seals that you can tweak as the door settles over time, ... then you should be OK. Big doors are heavy, and put a lot of stress on the framing as they open and close, due to the long lever arm, so you need to really beef that up heavily, to minimize sag, warp, twist, etc. over time. That's why you need the adjustable seals: so you can compensate for the movement over time by simply pulling off the protective caps and adjusting the seal positions.

Quote:
Would any of these doors need additional mass?
The surface density of each door must be AT LEAST the same as the surface density of the leaf it is in, and preferably higher. So yes, you will need more mass. You will also need at least double seals on each door, perhaps triple, considering your need for very high isolation, so I'd suggest adding the extra mass in two layers, each offset all around by a margin that is the width of the seal plus a little extra clearance.

Quote:
So to make sure I have more mass than that I will go with 3/4in. laminated glass on exterior leaf and 1/2in. laminated glass on inner leaf. ... Or should I go 1/2in. on exterior and 3/4in.
Same rule applies here: the surface density of each pane must be AT LEAST the same as the surface density of the leaf it is in, and preferably higher, plus the air gap must be AT LEAST the same, and preferably high. Considering that there is no insulation in the cavity between the panes, in reality you need to compensate for that by having more mass and/or greater depth of the air cavity, or both.
Quote:
Does it matter?
Yes. Very much.

- Stuart -

In the seal I will place some bags of desiccant to protect against moisture.

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PostPosted: Tue May 29, 2018 3:50 am 
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Posts: 16
Location: Arcata, California USA
Quote:
No no no! Never have TWO vapor barriers in a wall! That will trap moisture inside the cavity, and you'll end up with all kinds of nasty things... Only ever have ONE vapor barrier, assuming you need any at all. If you do need one, it normally goes on the side of the cavity that is warmer.


Thanks for clearing this up. My draftsperson said that the building code will require we put a layer (tyvek) on the exterior wall so I told her to remove the other vapor barrier.

Quote:
You are only calculating for sensible heat load: what about your latent heat load? You say you live in a very high humidity area, so your latent heat load is likely to be higher than average.


It is extremely rare to have "muggy" days here. So I was surprised when I looked at data on relative humidity for my area. It was consistently in the 90's year round. I read that mugginess (not sure if that is a word) is more related to the dew point. So I learned that you can have high relative humidity without it feeling muggy. I added an ERV to my plan based on the relative humidity data than how it actually feels.

Rod mentions that the ASHRAE "Ventilation Load Index" (VLI) separates latent and sensible loads for comparison. VLI for Arcata, CA listed the latent load as .1 ton-hours cfm per year and sensible load as 0.0 ton-hours cfm per year. With 6 people at 15cfm per person = 90cfm needed. So .1 x 90 = 9 ton-hours or 108,000Btu's of dehumidification per year and 0 tons or Btu's of cooling required per year. Does this mean that the latent and sensible loads are about equal when bringing in fresh air?

I am fuzzy on how this all connects. Any clarity about this would help.

Quote:
Don't forget to take that into account. At a rough guess (I didn't do the math), I'd say that your total heat load is going to be around 14,000 BTU, so you'd need a 2 ton system, at least.


I calculated a maximum of 16,170 BTU. Gear and lights = 9,578 BTU; People latent at 70% = 4,613 BTU and sensible 30% = 1,979 BTU.

At minimum 1,280 BTU. Equipment would be a computer and a few lights which would be approximately 250watts and myself alone at 1.2 met rate. That would be 853 BTU + 162 BTU (Latent) + 265 BTU (Sensible).

The LG condenser is a 2-ton system with Cooling mode of 24K BTU capacity and Heating mode of 27K capacity. Isn't that plenty? What am I missing?

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Does 42inches instead of 36 inch standard pose any problems?
As long as you can find suitable hinges to take that heavy load, and as log as you have really firm anchoring for those hinges, deep into your rough framing, and as long as you can find an automatic door closer that can handle that weight, and as long as you use adjustable seals that you can tweak as the door settles over time, ... then you should be OK.


Got it. Thanks. I think I will go back to 36".

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The surface density of each door must be AT LEAST the same as the surface density of the leaf it is in, and preferably higher. So yes, you will need more mass. You will also need at least double seals on each door, perhaps triple, considering your need for very high isolation, so I'd suggest adding the extra mass in two layers, each offset all around by a margin that is the width of the seal plus a little extra clearance.


Like this:
Attachment:
Both Doors Hung.jpg


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So to make sure I have more mass than that I will go with 3/4in. laminated glass on exterior leaf and 1/2in. laminated glass on inner leaf. ... Or should I go 1/2in. on exterior and 3/4in.
Same rule applies here: the surface density of each pane must be AT LEAST the same as the surface density of the leaf it is in, and preferably higher, plus the air gap must be AT LEAST the same, and preferably high. Considering that there is no insulation in the cavity between the panes, in reality you need to compensate for that by having more mass and/or greater depth of the air cavity, or both.


The mass for the exterior wall is 5psf (2x 3/4OSB) and inner wall is 5.25psf (5/8 drywall and 3/4 OSB). According to igamerica.com, 1/2" thick glass = 6.46psf. 3/4" = 10psf. The gap between would be 8" - 5/4 = 6"-3/4. Plus it is laminated. In your experience, what glass sizing would you use on this wall? 3/4" and 1"?

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LG AHU max airflow rate = 547cfm = 547/300 = 1.8sq.ft. = 259 sq. in.

So working backwards, the duct size at supply register could be 22x12, 18x16, 20x14, 26x10. I choose the 22x12. Adding 1" duct liner all around comes to 24"x14" duct with a Nailor 24x12" diffusor.

The silencer boxes would need to be large. The silencer would have 3 baffles inside each with the same cross sectional area of 14x24. Plus 1” duct lining added and 1.5” OSB for shell. Thus the outer dimensions of box would be 19”x 27". The space between baffles would be 14". Baffles would be 1" plus 1" duct liner = 3". So length would be (4x14) + (3x3) = 65" plus 3" OSB = 68”. So total dimensions would be 19”x 27"x68”. Plus ideally a sleeve leading to register of 42".


Can you please check my silencer dimensions? Did I do this right?

Thank you again! I really don't want to screw anything up prior to building.


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PostPosted: Thu May 31, 2018 3:50 pm 
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Location: Arcata, California USA
Spoke with my HVAC person today. He said that LG requires installers to go through a certification before installing AHU and ERV's. Because we are only using one room, the certification was not required but by not being certified the warranty drops from 10 years to 5 years. The closest certification is in Sacramento which is 200 miles away and takes all day to complete. So he will install it without certification. The good news is he understands that studio HVAC is unique and he is listening to me and the advice I have gotten on this forum!

Tomorrow we will plan where everything will go in the building. Any feedback from my last post would be great.

Thank you!

Howie


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PostPosted: Wed Jun 06, 2018 2:45 pm 
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Followed over here from viewtopic.php?f=2&t=21546&start=60 All I can say is that it looks like you have put good planning in place!

On a personal note my wife's grandmother lived in Ferndale until she passed several years ago. We LOVED visiting her and the beautiful area she lived in. Lovely place and very inspirational... "hey honey, I'm going out for a walk." ..."Oh, where are you going?" ..."Just for a stroll in the Redwood forest...." :yahoo:


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PostPosted: Wed Jun 06, 2018 3:58 pm 
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Location: Arcata, California USA
Hi RickLee,

I am pretty happy with the planning. Thanks. I was glad to find this forum one year ago. I still have much to learn. It is getting closer to a reality. I should be submitting a plan to the building dept. in the next couple of weeks! If all goes well I should be breaking ground in August.

On the personal note, it's funny you mention Ferndale because I was there last week on a hike through the redwoods and the old cemetery. It had been a few years.

Howie


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