Cyeazel's project studio...... planning and preparing

Hey cyeazel, you're really going places now. 8) I think you're getting really close to drawing up some detailed plans and specs. Feels good to be dislodged, huh? --Keith :mrgreen:

Thanks guys. I'll be posting drawings asap. Steve, I wish the stupid Skp files (sketchup files) that I sent you a few months ago weren't so hard to navigate thru. I drew every possible detail/flanking path possible. Oh well. Oh and in terms of thinking about all possible sound paths into and out, that has been on my mind for the last year now. The only NON 2 leaf walls will be the block walls because they are hollow. This actually isn't that big of a problem though because any intruding sound or sound leaving thru the block walls will go out into a factory or an area of the building with no one in it anyways. All intruding factory noises coming in the rooms are higher frequencies too so I won't need to worry about the compromise in low end performance. I still want to beaf up the block walls though with at least one more layer of 5/8" to further negate the three leaf affect brought on by newly framed walls. As for the ceiling system, I'm hoping that the existing outer leaf (steel layer w/ 3in rubber on top) in conjuction with a 2ft airgap w/insulation and a newly framed inner leaf (2 layers 5/8" drywall w/ green glue b/w) on kinetics hangers will offer an appropriate MAM resonance to match the floor. I'm also fortunate that my exising HVAC system has very minimal flanking issues between floors. The ducts are already insulated and most of them have 4 or more 90 degree turns. My HVAC guy told me that any new ductwork that I'd need to add would not pose a problem for the system meaning that it is plenty powerful enough to supply more airflow. Alright, I'm rambling out of excitement. I'm done with this post.

Just got off the phone with Kinetics and have been informed that going with 4 inch pads on the rim system would not be cost affective for my goals. The increase in price far outweighs the benefit the extra inches give me. Looks like I'm gonna go with the 2inch.

So what they're saying is that there isn't a "sliding scale" to their pricing? (meaning, 4" costs about twice as much as 2"?) Still, their test results aren't shabby at all, although I'd still do the extra drywall layers between plywood. As far as your block walls causing 3-leaf effects, I had a small conversation with the god of isolation (Eric Desart) a few months ago on this subject, and although I thought it was Eric who told me a hollow block wall would act as two leaves, he claimshe never said that and that the block are stiff enough NOT to cause this, just treat them as a single leaf of mass. This is NOT to say that sand-filled ones wouldn't be BETTER, if that were an option. (Not saying Eric changed his mind on this, odds are it's MY mind that "interpolated" something :oops: ) I too am sorry your skp files took so long to move around in with my system, I know how much time it must have taken to draw all that detail - mainly, I'm just concerned about flanking or multi-leaf paths; but it sounds like you're all over that one. Speaking of which, have you and Kinetics decided it's OK to float your inner walls on the floated floor? I think this could be a fairly important step, since those walls would otherwise be a direct flank thru the existing concrete floor... Steve

Haven't gotten to the point of figuring out how many pads and what spacing I'll need on the RIM flooring to support walls. As far as load capacity goes, I'm good, but haven't gotten to the point of figuring how many extra pads etc.etc I'll need for the RIM flooring. I'll for sure be talking with someone at Kinetics about that. Sand filled would be awesome but it's just not practical in my situation. Some of the block walls are 20 or more feet high and if they "pretty much" act as one mass, I'd rather leave them as they are. 1) So should I not bother with beefing up innerside of block walls then, at least in terms of reducing 3 leaf affects? 2) One more question before I forget. The plan is to have a new suspended ceiling on Kinetics hangers which will be just over 8 ft in height. My question is although just the sprinkler heads will be exposed, should I still go ahead and wrap the rest of the sprinkler pipe with the butyl rope above the ceiling, or will proper sealing around the ceiling penetrations and insulation above be enough?

As far as your block walls causing 3-leaf effects, I had a small conversation with the god of isolation (Eric Desart) a few months ago on this subject, and although I thought it was Eric who told me a hollow block wall would act as two leaves, he claimshe never said that and that the block are stiff enough NOT to cause this, just treat them as a single leaf of mass. This is NOT to say that sand-filled ones wouldn't be BETTER, if that were an option.

:roll: :roll: :roll: :roll: :roll: :roll: How much time I've spent pondering about how I'm going to fill my CB wall... and suggested this to others on this forum. Hmmm wondering how much gain would be had filling a CB wall with sand (at least in my circumstance). Maybe the subject is worthy of it's own thread :twisted: Marc

Concrete weighs about 150 PCF, dry sand weighs about 100 PCF; if your block are 8" thick and 1" each side is concrete (these are typically NOT made of the same density concrete as poured, but less) then filling with sand would increase mass by (allowing for webs) maybe close to DOUBLE - so the mass of this leaf would be nearly twice, plus sand has quite a bit of damping properties (ask the GG man about damping) Sooo, strictly from a mass law standpoint I'd say (for that particular leaf, NOT the entire 2-leaf wall assembly) it'd improve TL within the mass law range by AT LEAST 6 dB; however, memory may not serve too well so here's a link http://irc.nrc-cnrc.gc.ca/pubs/ctus/13_e.html HTH... Steve

Here's my non-expert take on the hollow concrete block wall thing. Since the jury has reached its verdict in favor of aquitting on the charge of third leaf in the first degree... (Or is that first leaf in the third degree? :roll:) ...and the intent of filling them with sand was twofold -- increase in mass and bridging of what was thought to be two leaves into one -- given one of those goals is unnecessary, I would think there are far easier methods for achieving the other "still legitimate" goal. In other words, yes, adding mass is good and you should do so, in a method that is much easier and more practical than filling the blocks woth sand in a retrofit sitution. If there are no concerns about moisture wicking from the other side of the blocks, then I think perhaps ¾" plywood as a base using Tapcons, then one or two layers of 5/8" drywall with screws that will penetrate all ¾" of the plywood, would be a winning plan. Throwing Green Glue at it also would, I think, pay off big. If moisture is a concern, then maybe... cement board...? At the very least, moisture resistant drywall (the green stuff). Then, of course, there'd be (ideally) a separately framed inner leaf assembly. --Keith :mrgreen:

According to the article it does seem to agree that hollow block walls (50% solid blocks as the article calls them) act as one mass because of the fact that the it says the best way to mount gypsum is on resilient channels or separate framing all together.

Yup; that terminology is part of what threw me for a while too... Steve

Okay so here's my current floor plan where new inner leaf wood frames team up with existing outer leaf block walls.

Only mistake I see is that your sketch is 1082 pixels wide; if you just trim the black it should be fine. Other than that, you're there... Steve

Sorry bout that. I know the rules and I tried to trim it down. Obvioulsy not near enough though. I'll fix that right now.

Steve. after looking at the drawing again, I realized I don't have the floated floor in contact with the perimeter iso board. Should I? Oh, and I forgot to include mineral wool insulation for the inner leaf frame but I for sure am going to use it.

PIB is mainly to keep retrofit floors from touching the walls - in your case, you have other ways to keep this from happening (the rim system with a surrounding "spacer" - I'd keep the PIB where it's at because it's somewhat softer, which will minimise any flanking between your inner floor/wall and the outer, but I doubt it'll make much difference in this case. Thanks for the trim job... Steve

This is my plan for the ceiling. There will be insulation above the inner leaf as well. I just couldn't find a good way to draw it. Is this lookin alright?

Hey cyeazel. Curious, on your floor-ceilingplan_edited.jpg 1st post on this page you have "existing 8x8x16 hollow block wall w/ one layer of 5/8" drywall" Is the 5/8" drywall existing or are you planning to add it to CB wall (CB = Cinder Block, Concrete Block). Sorry if I missed this skimming your thread. Marc

Good observation Marc, I actually forgot to include it in the second drawing. The drywall on the concrete block is already existing. It ( the drywall) only covers the block wall up to 8 ft. The remaining 2 ft of the block wall is bare. In other words, the block walls are 10 ft high with drywall mounted up to 8ft. That actually raises another question. Is it important that I cover the remaining 2 ft of bare block with drywall to keep the mass consistent or will this not be that big an issue if left the way it is?

Good observation Marc, I actually forgot to include it in the second drawing. The drywall on the concrete block is already existing. It ( the drywall) only covers the block wall up to 8 ft. The remaining 2 ft of the block wall is bare. In other words, the block walls are 10 ft high with drywall mounted up to 8ft. That actually raises another question. Is it important that I cover the remaining 2 ft of bare block with drywall to keep the mass consistent or will this not be that big an issue if left the way it is?

I don't think it'll make a big dif to not cover the other 2ft with drywall. Only concerns there would be as the IRC article stated... Whats the finish on the other side of wall? The finish will help tighen the seal of CB's increasing ISO, but the CB wall STC and TL with out finish should already be above your goal. You may want to double check and see if that drywall is furred out from the CB wall. (Drywall attached to furring strips not directly to CB) If it is then there is a 3/4" to 1" space inbetween the drywall and CB... 3 leaf. Marc

The drywall is glued and not furred off the blocks. I do have another block wall on the other side of the room with 2 layers of 5/8" on furring strips. I hope I can remove those 2 layers that are on furring channels without messing them up too much. I'd like to reuse the drywall if possible.

Will you be adding blocking between your new ceiling joists? The "staggering new joists between existing joists" (or, in your case, trusses) concept is a good one, but I noticed Rod calls for the use of steel braces in an "X" formation in his book in order to keep the joists upright. As a result, the vertical clearance is reduced by a few inches, since the intersection of the "X" has to be under the existing joist (or bottom chord of truss). Also, since you won't be tying your new ceiling joists to your inner leaf wall frames, you'll need to use resilient sway braces to keep your walls upright. Finally, you'll want to install drywall in this sequence:

• 1 layer on the ceiling
• 1 layer on the walls
• 1 layer on the ceiling
• 1 layer on the walls

This makes for a better seal, and it helps to support the outer edges of the ceiling layers. --Keith :mrgreen:

Keith, what's your opinion on these sway braces for the walls?http://kineticsnoise.com/arch/kwsb.html Also, are these sway braces absolutely neccesary? Would I have structurall failure without using them?

Those are cool... Similar to the ones that Rod points out in his book as I recall. How else will you get the wall to stand up straight? --Keith :mrgreen:

I thought that firmly fastened soleplates plus wall-ceiling perimeter sealing would be enough once the whole "inner" box is completed. But if this is way off, then I'll for sure do what needs to be done. I just know that the sway braces will cost a lot that's all. If there's any other way, let me know.

If you were planning to firmly attach your inner leaf ceiling joists to your inner leaf wall frames, you wouldn't need sway braces or anything special. However, since you don't have that luxury, you need a way to maintain the structural integrity of your inner leaf wall frames. The fact that they'll be softly touching your inner leaf ceiling via a resilient seal does not address this need. You need something to keep the tops of your walls from leaning. (The anti-sway braces to which you linked are, I think, meant to make the walls less likely to bow when pressure is applied...? :roll: What you really need is something to keep the tops from moving.) Take it from me -- even with my wall frames tightly secured to the floor with 5/8" steel bolts, they definitely wanted to tip if I put any pressure on them. The leverage that 8' to 10' studs have on soleplates is extreme -- perhaps enough to break the soleplates if I had been so inclined. Once I tied the walls to the new ceiling joists with my seismic ties, that issue went away. Well, they still give a little, but that's because I have no sheathing or drywall on the framing yet. Once that's attached, I'm sure the box won't hardly give at all. And I must confess that I have a couple of temporary braces that tie outer and inner leaf framing together, just to keep things more stable until the sheathing goes up. Are you following Andy Eade's Rotten Basement Conversion Thread? He faced this issue last week and opted to fabricate his own solution, partly to save money and partly to save time, as he had framers due on site in less time than he'd be able to get the real McCoy delivered. :roll: I don't have Rod's book in front of me, but you may want to do some more studying on this subject. I'm pretty sure he covers it. --Keith :mrgreen: