Piano room over slab

Steve...brilliant. F***in' brilliant. Let me see if I understand the air space concept...it sounds like you're saying I should fill the entire cavity with regular insulation if I can? Correct? Every answer gives me another hour of sleep! Thanks a million for all your work. Best, Phil

Yup, that's what I'm saying - also, if you use kraft-faced insulation for this, acoustically it won't make any difference inside the wall which way the paper goes - moisture-wise, though, if you already have moisture barrier taken care of with your outer materials, you should get UN-faced fiberglass to avoid trapping moisture within the insulation cavity and the mold that will result... Steve

Steve, Thanks again. It's actually easier to fill that space with blown-in cellulose, and about the same price, so we were wondering which one (fiberglass or cellulose) would be better. I haven't seen them compared in the forum, but I'll check again. Thanks. Phil

Depends on the method - the spray cellulose that gets hard works good for heat, but bridges inner and outer leaf too much for sound isolation. IF the blown in stuff will not settle too much and doesn't "set up", it's about the same performance as fiberglass for sound. How would you blow the stuff in when you already had the 703 in place - over the top? seems kind of "iffy" for full coverage that way... Steve

Steve, You must be from the big city, boy. It's a grain bin...we haven't sealed the opening in the top yet. Most grain bins, maybe all, have a hatch on top to put grain through. Since we're blowing in the cellulose, we can just do it either as we put the 703 and sheetrock on, or just blow it through the hatch. I found a quote on insulation. Seems like if the cost is equivalent, and the low frequency blocking is equivalent, then blown in loose cellulose would be the way to go. Thanks for the answers! Here it is: Quote: IRC 02-108 Adding a sound absorptive material inside the cavity of a single stud partition (wood with resilient furrings or steel) or a staggered wood stud partition increases the STC rating by 5 to 9 points depending on the type of sound absorptive material used. For double stud partitions, an increase of 10 to 13 points was obtained depending on the amount of glass fiber insulation added to the cavity. Generally, at low frequencies, the increase in the transmission loss of a partition obtained by adding a sound absorptive material inside its cavity is equivalent regardless of the material used. Above 250 Hz, mineral fiber and blown cellulose give the best results; mineral fiber insulation provides slightly better transmission losses than glass fiber, especially around the critical frequency. Also, in the case of glass fiber, a greater transmission loss can be achieved by using denser batts. With the exception of sprayed cellulose, the best transmission losses were obtained when the entire cavity of the partitions were filled with a sound absorptive material. When the entire cavity is filled, caution must be taken not to use a material that is too dense, otherwise a mechanical coupling could occur between the two sides of the partition which could result in a degradation of the sound isolating performance of the partition, as was observed in the case of a partition whose cavity was filled with sprayed-on cellulose.

Not from even a SMALL city, live on 10 acres 15 miles from the nearest small town; if it moves on 4 legs (or two, with feathers) I've probably killed it, gutted it, cut and wrapped it, beheaded it, eaten it, usually raised it... I just didn't remember or check how far along you were on that part of the construction... Steve

Just joshin' witcha, Steve. I lived in Oakland for 27 years.

You poor bastard :( sounds like you're all better now though :D

Yeah...I'm doing better, but I'm a little worried about you. You're starting to look like a German Shepherd.

Yeah, place has been goin' to the dogs lately - although that's a pic of an Akita - we lost ours last year, still hurts. That dog was smarter than most of the people I work with, and NOBODY was ever dumb enough to challenge him - 150 pounds, jaw power that would make a pit bull envious, and knew who belonged here and who didn't within 24 hours of when we got him at 4 months old - prob'ly get another one as soon as our male dobie's gone... Steve

Steve, Just got back from playing at Big Sky, Montana, camping, and playing at Asilomar on Monterey Bay. That's the life. Sounds like a great dog. Ours is a 110 pound black lab. I don't know...I always thought it was unfair that those great beasts live such a short life. Then, I decided that they're just teaching us about dying. Studio is getting closer to done. Had to hire some new rockers, (my other one is a shop teacher and just started school) and hope they didn't mess up too much. All the best, Phil

Sounds like a fun time - we used to live in Santa Cruz, til the idiots moved San Jose into it - then we knew it was time to leave... Steve