Mighty! Productions studio design and construction

Thanks for moving the thread Steve. The existing floor above is comprised of 2x10 joists (Douglas Fir Grade 2 I presume from the stamp on them) 24"oc, topped with 3/4" tongue and groove decking, topped with carpet and padding. The span is 15' from the edge of the steel beam to the concrete wall. My intention is to beef up with 2 layers of 5/8" drywall. The inner ceiling will be supported on new joists supported by the inner walls, interleaved between the current joists. I have 7'8" of clearance to the existing joists, so Im fairly confident I can keep the room ceiling height at 7' or greater. Yes, I believe I have modeled the room with stud's on 16" centers - I didnt bother changing the wall tool parameter in Sketchup to 24". My plan is for 24" oc everywhere. I believe I need to consult a structural engineer on my current joist situation. By my calculations, the current construction is already insufficient (without adding any beef). I highly doubt a major builder would make this sort of mistake, so I assume I am not calculating things correctly. Does anyone know what the going rate for a consult like this should be? If I do need to sister my joists, is it an option to do this below the beef layers of drywall (sister the current 2x10 with a new 2x8)? I would hate to rip down the beef that I have already (perhaps prematurely) hung.

MightyM wrote:

I believe I need to consult a structural engineer on my current joist situation.

Agreed... I was just going to say that, but you beat me to it. ;-)

MightyM wrote:

By my calculations, the current construction is already insufficient (without adding any beef). I highly doubt a major builder would make this sort of mistake, so I assume I am not calculating things correctly.

It's possible. There are a lot of variables -- species of lumber is one of them. Deflection allowed in the codes is another.

MightyM wrote:

If I do need to sister my joists, is it an option to do this below the beef layers of drywall (sister the current 2x10 with a new 2x8)? I would hate to rip down the beef that I have already (perhaps prematurely) hung.

I'll defer to the structural engineer, and/or to Rod, on that question. --Keith :mrgreen:

I was able to consult(via email) with a structural engineer on my issue. He felt my joists were a bit over spanned, and would benefit by sistering them with either 2x10 or 2x8 lumber. I've attached the pics that I sent him to describe my situation. I've elected to go with 2x8 lumber so that I dont need to pull down my beef up sheet rock. I am planning on nailing the joists together, as well as bolting them together every 36" or so. Given the extra strength, is it safe to say that I would be ok addinng my inner dry wall using resilient channel instead of building a independant inner ceiling? Since I will need to span about 14.5', I'm afraid using 2x6 joists wont cut it, and going any bigger will really cut into my headroom. What about the engineered laminated joists. I understand those are quite a bit stronger. Is there a span calcutator for that stuff?

kendale wrote:

• Monitor height – woofer at ear level (avoid mid point of floor to ceiling measurement – either sit higher or lower if necessary)

I thought it was more important to have the tweeter at ear level than the woofer . . .

I'm just about done with the beef up work, so I'm mentally moving on to the inner ceiling construction. Because my joists were over spanned to begin with, I'm not too comfortable with hanging two more layers of drywall on them with resilient channel. Because my span in the control room will be about 14.5', I need to use a 2x10 joist or larger for an independant isolated ceiling. Using that large of a joist with the traditional cross bracing (as shown in Rod's book) will eat up way too much head room. I noticed that it seems acceptable to straight block between joists when there are obstructions preventing cross bracing (such as ducts, plumbing, electrical, or in my case another joist :? ). So, I've devised this plan for my inner ceiling construction (see attached). I sketched out my plan next to the recommended construction in Rod's book. Comments are welcome......

Sistering all your joists with 2x8's should give all the strength you need to hang RC or RSIC clips and channel - you asked whether nails or screws for the sisters, the answer is nails - I would clamp them together using construction adhesive, then use 14d nails (or short 16's) and nail at different angles (toenail is one term for this) while the clamps are still in place. Nails about 8" apart, staggered along the boards so no two nails are in the same grain line. Be sure to put any edge knots UP - this puts them in compression and they won't weaken the joist (as much) Engineered lumber products - I've yet to see span tables, these seem to be proprietary. Only way I've heard of to get info is talk to a rep, tell 'em what you want to do, and ask which of their products can span it. This practice reminds me of ads that show you stuff and say "call for price" - smells like a fishing expedition. GuitarStv - yes, tweets should be either at ear level, or AIMED at them. However, you do NOT want woofers centered between ceiling and floor or they will be in a null. See my thread "are my speakers in a null", in Acoustics forum. HTH... Steve

I for one am not comfortable with this... First of all, my understanding of "sistering" being used to strengthen a joist is only effective if the bearing edges are equal to the joist being sistered. That drawing makes it appear that the sistered piece is higher than, and therefore not bearing upon, the top plates at each end of the joists. And you should always use nails for framing... Nails kick screws for shear strength, and you're going to need shear strength in that application (I would think)... :roll: --Keith :mrgreen:

I had the same feeling originally. Adding in more joists that bear on the foundation and I-beam will effectively reduce the load per joist, thus accomplishing the task. Doing what I have done does not reduce the load per joist, but does increase the strength of each joist, allowing it to carry more load. I havent done the calculations to compare the two methods, but my gut says the results would be near equivalent. The structural engineer seemed ok with this approach, so I went with it.

When it comes to (over)loading joists, I don't trust guts. ;-) I also don't trust structural engineers seeming to be OK with something. Unless someone with a collection of letters after their name says otherwise, I'm going to stick with my "I don't like it" stance. --Keith :mrgreen:

Given my uncertainty over exactly how much load those joists can take, I am leaning toward building the inner ceiling independant from the outer (as I sketched earlier). I feel there is also less of a chance of screwing up and mechanically shorting out my isolation this way as well. And, if my living room floor should collapse, at least I'll have another load bearing structure to break or slow down the fall! :shock:

I'm getting close to beginning framing, and I wanted make sure my plan looks sound (as I have never framed anything before). The first pic shows a top view of all the base plates with full length (floor to ceiling)studs. In particular, I'd like to know if I've planned the corners properly. Im a bit short on space between the tiolet flange and the planned wall. I know there is a minimum dimension for this to meet code, but I'm not sure what it is. I want to be sure I've alotted the proper gap in my base plates for my yet to be purchased doors. Can anyone tell me how much space over the nominal door width (32" and 36") I'll need? The second pic is an iso view of my plan thus far, including door and window cripples and headers. I've been using Solidworks to design this. If anyone has 3D CAD capability, I'd be glad to send them my file (stp or igs) to review. Its currently about 3MB.

Generally speaking, you'll need to have a rough opening that is 2 inches wider than the width of the door (e.g., a 36" doorway requires a 38" rough opening). I'm with you on doing the separately framed inner leaf walls and ceiling, assuming you have the overhead clearance to do that. What is your existing floor-to-bottom-of-ceiling-joist clearance? You'll want to come up with a floorplan that avoids having parallel walls. Perhaps you can/should start a thread in the design forum, following all of the guidelines there of course. --Keith :mrgreen:

Will two inches over the size of the door account for the 5/4 jams that Rod recommends in his book? So the idea is to leaving the opening a little large, and take up the slop with shims between the framing and the jams? Doing the seperate ceiling as I described earlier should leave me with a 7'2" ceiling if I did my numbers correctly. I'll be double checking that more thoroughly soon. The floorplan that I decided on is on the 2nd page of posts. I will be building bass traps and slot resonators within the rectangular room to break up the parallel surfaces. Any idea on the minimum distance between the toilet and the wall? Also, I have been going crazy trying to find a source for solid wood flat panel doors. I thought I could find a salvage building supply place that would have used doors, but no luck so far. My office is full of doors exactly like what I'm looking for. I wonder if they'd miss the doors to the conference room?......

MightyM wrote:

Will two inches over the size of the door account for the 5/4 jams that Rod recommends in his book? So the idea is to leaving the opening a little large, and take up the slop with shims between the framing and the jams?

Oops... :oops: No. I'm basing that on very old data that I got prior to his book being published. :roll: I'm thinking (guessing) you'd need to add 3½" to the width of the door. But I wouldn't take my word for it! :oops:

MightyM wrote:

Doing the seperate ceiling as I described earlier should leave me with a 7'2" ceiling if I did my numbers correctly. I'll be double checking that more thoroughly soon.

What is your clearance right now? --Keith :mrgreen:

I've finally got some framing done (will post pics soon). Its nice to see some visible progress. Before I get much further, I need to tackle my HVAC silencer boxes. I'm having a hard time finding a source for acoustic duct liner or board. The internet seems full of info about it, but no where to get it, and the local big box stores dont seem to carry it. Also, I'm having a hard time finding good solid wood doors. Where do used office doors go to die? Any tips for sourcing these materials is greatly appreciated. Just to follow up on a previous question: My clearance from concrete to inside joist is 7'8". I figure with flooring and drywall, I'll be around 7'5".

I special ordered my doors from Lowe's. They are Jeld-Wen flush doors with the ProCore core. The ProCore had a bit higher STC than other cores. They are super heavy! I think they cost me about $80 a piece.

There's a place here in Cinci that has all sorts of old building materials including TONS of doors, steel, solid core, hollow core, you name it. I think a 36"x83" solid core door runs $35. Plus they have hinges, locksets, etc.... I use this place all the time for rental property and such. I salvaged my future studio doors this way and have them stored for now, including Schlage hardware.... :D I'm sure Chi-town has something like it. -ashley

Summer has been busy, and progress is slow. Here are those pics I promised a couple months back.....

I'm working out the design of the HVAC returns. I'm planning on running a plywood return chamber from the return in each room. These will be fixed to the inner walls. Both will run to a central return chamber fixed to the outer wall. I will couple these with 6" dia. flexible rubber couplings. The chambers will be caulked and lined with duct liner. I am planniing on mounting a variable speed centrifigul in line fan in the central return chamber to provide control over flow. The fan will be accessible from the storage closet under the stairs to facilitate repair. Take a look at the attached images to get a sense of what I working on. I would appreciate any feedback to avoid pitfalls, or make things easier.

Very little progress was made over the summer, but I finally got back down in the basement and completed the main HVAC return silencer box/exhaust fan install. Also framed up the isolation booth. All my door and window openings are yet to be framed because I havent got the doors and windows fabricated yet, and dont know what the final sizes will be.

I have found new motivation to pick up the pace on my studio construction - I need to clear out the bedroom where my "studio" is currently set up to make way for a nursery! The baby is coming in October - the clock is ticking. I've gotten back to work framing, working out the details for my doors, window, and HVAC soffits.

Great to see you back in action, mighty!

Thanks for the ecouragement Ro. I ordered my automatic door bottoms (3) yesterday. I chose the Zero International 368 for my application (no threshhold, finished concrete floor). I ordered direct from Zero, and got a lot of good advice from Dave Crocco there at Zero. Dave gave me 20% off list price ($105), so they ended up being $84 each plus shipping. Just like every other materials decision I face for this studio project, this started out as a mental puzzle to me. Trying to figure out what type (brand and model) I needed, and where to get it without getting robbed seems like the constant challenge. I settled on Zero because their product seemed to be well regarded, and the cost didnt seem too out of line with other equivalent product (Pemko), and I think its worth paying a bit more when you get good service (as I did speaking with Dave). The 368 was recommended because it has a double seal, which is ideal for me becuase I will have to threshhold to seal against. Next task - find the appropriate door closers. There are a butt-load of variations out there!

After having sealed up my main HVAC return silencer box months ago, I've become paranoid that a) fiberglass will get blown through the rest of my house, and b) that the lining will come loose over time and create a blockage. I saw somewhere that cheese cloth could be staple over the top of the liner to keep stray fibers from getting blown out. I started trying to staple in the cheese cloth, and am less than happy with the quality of my work. I also noted that the insulation pulls off the staples fairly easily. I tried to insure the insulation would stay in place by tieing string across it. Again, I am less than happy with the quality of my work. If anybody has any suggestions to do a neater job with this, I'm all ears! Did I mention I really dislike working with fiberglass insulation!

I've got the first of my supply boxes put together. I skimped on mass here, only using 1/2" OSB, so I suspect I may have some isolation leakage related to my boxes. I'm not looking for perfection, and I feel that this construction should do the job with my time and budget constraints. All inside surfaces were lined with acoustic duct liner, and then covered with cheese cloth to (hopefully) ensure that none of the fiberglass gets into the air. Once the box was screwed together, all the joints were caulked and sealed with acoustic caulk. Now I just need to finish the electrical and HVAC runs that will go behind it before I mount it into the soffit.