whoops! insulation not in contact with 1st layer

I think I did a bad thing. :shock: I know, big surprise. After not finding this forum until too late, I made a few mistakes. Hopefully they are not too critical. First, I used insulation with paper vapor barrier instead of unfaced. The paper barrier toward the room. No big deal... I think. Second: I wanted to glue the first layer to the studs, so I stapled the paper inside the studs to leave the stud faces exposed for glue. Most of that is okay, however there are places where the insulation is not going to contact the first layer. I am thinking this is a problem since the insulation is the dampening agent for the walls. Correct? The wall that is the biggest problem is an outside wall. I am in N. Central Texas in an area where vapor barriers are not much of an issue, assuming that whole global warming thing doesn't happen any time soon. :mrgreen: The first layer will be 3/4" OSB, the second wil be 5/8 drywall. Questions are: 1. How much of a problem is this? 2. Rather than rip all the insulation down and start over, can I use something to fill in the gap between the 1st layer and the insulation? I have a couple of ideas (more insulation glued to the paper, etc.), but I'm very open to suggestions. Thanks! Scott

If you continue you'll likely build "bass traps" that have one obvious and one (not so) obvious resonance - the paper being the (not so) one. Need to know the current status of your project - what's done, what's planned. Pix or sketches would help... Steve

Steve, Not that bass traps would be so bad if they were the ones I need, but I think I'd rather avoid it if I can. :D Sorry, I have posted elsewhere on the forum about the studio progress. Was it poor form to post here? Should I have posted this on the other thread? I was thinking this was a different topic, that needed a different subject line. Sorry if I confused things. That being said, here is the breakdown of the studio. I am building a control room for my own, commercial, use. I am not looking for perfection, but I want to do as much as I can afford and is also practical for the space. Most of my recording is done on location, so this is primarily a mixdown space. I am in the country in N Central Texas, so it's pretty quiet out here most of the time anyway. I just have the occasional tractor, car with a boom box going by at 70 mph and a train about 3 miles away that I can hear on the quiet nights. The building is about 100' off the road. This is a box in a box design. The floor is approx 16'x13' with a sloped ceiling, 8' at one end and 10' at the other. Floors are 2x6 joists on U-boats with glass insul., stringers, 3/4" MDF subfloor and 5/8 plywood in layers. There will later be a hardwood floor. The floating floor is resting on a concrete foundation that's fairly thick, and dense (sinking anchors is rough). They used to run forklifts around in here. :) What I am working with now are the walls. It is an industrial steel building with 3 1/2" of glass insul. attached to the outer walls and ceiling. The inner walls are resting on sheetblock, then the floating floor (additional U-boats around the edges as suggested by Auralex). They are 2x4 studs on 16" centers with glass insul. The CR wall nearest the exterior is 7" from the building's exterior wall due to the steel supports for the walls. Sorry, I don't know how to post graphics without using a link, and I'm not real sure this will work. But here is a sketch of what I hope will be the final room. http://img352.imageshack.us/my.php?image=studioig2.png The red areas in the front corners are hollow areas I plan to fill for bass trapping. The blue areas on the side walls are glass. One on the right is a window, the one on the left is a sliding glass door that leads to a living/recording area. Most of those will eventually be covered with absorption of some sort when necessary. The ceiling is 2"x6: joists with a 1/2" plywood 1st layer and 5/8" gypsum face. The gypsum has been left with a gap around the edge to allow for the first layer of wall sheeting to be slid behind. Right now, the walls are open. They are simply 2"x4" studs with insulation attached as described earlier. Of course, the necessary AC, telephone, etc. have been installed. I had thought that the insulation would expand enough to overcome this issue, which for the most part it has, but there are several places where it didn't. I am guessing altogether in the range of about 50 square ft. (scattered throughout the room), mostly on the side walls where the glass is, which means much of it will be covered with the additional of the bass trapping (in red) or likely have 703/705 attached directly to the face. The problem exists because there is nothing but air behind the insulation. On the right wall, next to the exterior, there is a gap caused by the 7" wall girt that holds the steel together. On the left wall there is an unfinished room. So there is nothing pushing against the back of the insul. That will likely remedy itself, or is easily enough remedied when I finish the other room. Thank you very much for your patience and help. I know everyone here appreciates your time. Scott

Do you have access to at least one side of the insulation at this time? If so, I'd get some UN-faced batts and cut some strips to add to each stud bay; then look for some pallet strapping (the fiberglass or polyester kind) and some 1-1/4" or 1-1/2" roofing tacks (big heads) and nail this strapping across your studs horizontally at about 24" intervals, to hold the insulation in contact with your wallboard.... Steve

I have access to one wall easily. Another, I can with a little effort, so those are pretty workable, but there are two that I do not have access to. :( Pardon my ignorance, but how much effect is the paper going to have if I get some unfaced insulation and put it between the paper and the OSB first layer? I can get faced insulation and strip the facing off if necessary. One reason I had used the faced insulation is that I've been working on this room a little at a time (I have a place to mix/edit in another room) and I needed to be able to buy whatever I need locally without having to order it. My best supplier Home Depot/Lowes. The other reason is that I knew there was nothing behind it to hold it up in places and needed the facing to hold it in place. I know you're incredibly busy, so thank you so much for your help. Scott

I'm still not clear on what you have so far; you mention outer steel walls and inner 2-layer walls. Is that it? Is the steel well-sealed, or just so-so? How much sound isolation do you need? The paper is probably going to be the LEAST of your problems, but would have some measurable effect on isolation IF the rest of your construction would comprise an actual mass-air-mass system; just not MUCH of an effect. However, a lack of DAMPING of your wall panels (from medium contact with the insulation) WILL be noticeable. We probably also need to discuss ceilings; apparently your wall frames rest on the main floor instead of on the inner floated one - but a more detailed sketch would sure help visualize what's going on here. Posting pix - not too tricky. DRaw something in Paint, save it as .jpg so it's small enough file size, click the Browse... button, navigate to your file and double-click it - then click the Preview button to see if it's what you expected. For multiple pix, navigate to the LAST one you want and work your way back to the FIRST one (5 maximum) - Browse to each, select it, then click the Add Attachment button and repeat... Steve

Steve,

knightfly wrote:

I'm still not clear on what you have so far; you mention outer steel walls and inner 2-layer walls. Is that it? Is the steel well-sealed, or just so-so? How much sound isolation do you need?

Yes that is correct. The steel is well sealed. It is a typical industrial steel building. As far as "how much" isolation I need, it's is pretty quiet out here in the country anyway. My biggest noisemakers are the tractors going by occasionally and car stereos booming as they go by. The building is about 100 ft off the road. Other than that there's only a train about 3 miles away. I am mostly concerned with keeping outside noise out. There is never noise inside louder my monitors. I'm just trying to get as much isolation as I can without spending a fortune. And what I am doing, I want to do right (or as right as I can) to get as much bang for the buck.

knightfly wrote:

The paper is probably going to be the LEAST of your problems, but would have some measurable effect on isolation IF the rest of your construction would comprise an actual mass-air-mass system; just not MUCH of an effect. However, a lack of DAMPING of your wall panels (from medium contact with the insulation) WILL be noticeable.

That's what I was thinking and trying to find the easiest fix for. The damping problem, I mean.

knightfly wrote:

We probably also need to discuss ceilings; apparently your wall frames rest on the main floor instead of on the inner floated one - but a more detailed sketch would sure help visualize what's going on here.

No, the walls are resting on the floated floor. There is sheetblock between the wall plates and the floor Sorry for the confusion. The ceiling is 2"x6" joists with 1/2" plywood 1st layer and 5/8" gypsum second layer. The attic hasn't been insulated yet, but I have R-30 for that so far. The roof is the same industrial steel construction as the walls with 3 1/2" insul attached directly to the roof. >> An additional note. I am curruently working in a room inside the same building that is typical wood stud with 1/2" gypsum walls and about the only things I hear are the above loud tractors and car stereos and they are pretty faint. - If that helps - :) << Posting isn't so much the problem as drawing the pic. I'm a pretty awful artist, but I'll do the best I can and post it later tonight. Thanks again, Scott

If you're just using Paint, here are a few tips - Pick a color scheme and stick with it - I use the light brown for framing, light blue for gypsum, black for rubber (and borders of solids), light or dark gray for concrete or steel, green for fasteners or rebar, red for pointer lines, usually black for text, light or dark brown for dirt... You can build bordered solids by choosing the middle option in rectangle, ellipse, etc - then right click on the color you want for the fill, left click on the color you want for the border. IF you pick the LINE first, you can thicken your borders if you want. Then choose rectangle, and you'll get a thicker bordered, filled rectangle. Holding the Shift key while drawing a line forces it to be horizontal, vertical, or 45 degrees; useful in a long line to make it accurate. I usually set the background "soft" - click on the "A" or on the dotted rectangle, then choose the lower of the two colored block images that appear on the left. IF you want several items all alike, just draw ONE - then select it with the dotted rectangle tool, then [ctrl]c (for copy), [ctrl]v (paste) - while it's still got the dotted line around it you can move it anywhere on the drawing. IF you watch the coordinate display on the lower right, you can line up with another item and note the coordinates - then move to where you want, and one or the other coordinates will be the same when you're in the right position; then unclick the object and you're done. Note that these numbers will change each time you copy, pick up and "deliver" an object. There's a lot more, but I gotta go dig in my back yard... Steve

Steve, Here's the very basic floor plan. ( I hope. ) The exterior walls are corrugated steel. Pretty normal stuff. The brown lines are interior walls. Dark blue are windows. Green lines are doors. Obviously it doesn't show double walls, etc. I'm working on detail drawings. I just wanted to give you an idea of the space. Thanks for your patience. Scott

Here is the floor detail and part of the wall. The sheetblock is only under the floor plate, not on the entire floor. And also the exterior wall detail. Only the inner layers are not shown. They are not up yet. Interior walls are virually the same, except for the width of air space and the steel. It's very typical double wall construction. I'll get a detail on that tomorrow. Let me know if you need anything else Scott

Steve I didn't indicate on the drawings, but as previously stated, the insulation is faced. Thanks again! Scott