Hey, everybody..

Just about to fill my riser with insulation and am wondering..

- Can I use the "Kraft" (paper) faced insulation? (I have 3 rolls that I was going to use for something else..obviously would need to buy lots more..) Or, do I need to buy the paper-free batts? (Wondering if paper might resonate/snap with big bass [one sub is on the riser])

- Does R-factor make a lick of difference, or should I buy the cheapest (eg: R-13)?

- I see a lot of 3.5'' thick batts..riser is 13'ish tall. Would 4 stacked runs of 3.5'' be enough, or do I need to "pack" this down in the joist cavities somehow?

- My riser is built on U-boat isolators, so there's about a 1/2'' gap at the bottom. Do I need to line the joist cavities with plastic or caulk around the edges to keep the insulation fibers in? (Riser will be carpeted..maybe that's all I need?)

Thanks as always!

- B

Hey, everybody..

Just about to fill my riser with insulation and am wondering..

- Can I use the "Kraft" (paper) faced insulation? (I have 3 rolls that I was going to use for something else..obviously would need to buy lots more..) Or, do I need to buy the paper-free batts? (Wondering if paper might resonate/snap with big bass [one sub is on the riser])

- Does R-factor make a lick of difference, or should I buy the cheapest (eg: R-13)?

- I see a lot of 3.5'' thick batts..riser is 13'ish tall. Would 4 stacked runs of 3.5'' be enough, or do I need to "pack" this down in the joist cavities somehow?

- My riser is built on U-boat isolators, so there's about a 1/2'' gap at the bottom. Do I need to line the joist cavities with plastic or caulk around the edges to keep the insulation fibers in? (Riser will be carpeted..maybe that's all I need?)

Thanks as always!

- B

FYI:
I've seen countless posts here/other forums regarding "Fill it with sand" if you will have speakers or subs sitting on your riser.
Vibrations, vibrations.

I filled my riser with R38. I removed the kraft facing on it just in case it would ever vibrate.

For the stage I would definitely agree that sand filled is the way to go. However, for the riser, insulation is fine. I used a combination of r-13 and r-30. It's just what I had laying around. You could peel the paper off the r-13 but I don't think it would make a difference. My riser is made with 2 X8's.

http://i134.photobucket.com/albums/q113/judsonp/Home%20Theater%20Construction/Fallwinterchristmas2007229.jpg

Packed mine with R-19 faced (easy to staple.) No vibration issues.

FYI:
I've seen countless posts here/other forums regarding "Fill it with sand" if you will have speakers or subs sitting on your riser.
Vibrations, vibrations.

Ya know, that's a really good point..

Assuming you have Subs on BOTH the Stage and Riser..

Why would we use Insulation in the Riser, and Sand in the Stage?

Same logic should follow for the Riser as the Stage (sand reduces vibration via mass), right?

- B

Ya know, that's a really good point..

Assuming you have Subs on BOTH the Stage and Riser..

Why would we use Insulation in the Riser, and Sand in the Stage?

Same logic should follow for the Riser as the Stage (sand reduces vibration via mass), right?

- B

I agree, if your putting a sub on the riser you should fill it with sand - at least where the sub is sitting. No gear - insulation is fine.

One reason you would use insulation in riser with a sub on it and NOT sand is if you are using that Sub as an additional Tactile transducer.
That is what I do I have one of my subs on the riser sitting on the same support as my seats, it supplements the Bass Shakers that are mounted IN the riser very, very nicely.

Anyway as to what kind of insulation in a riser, just regular unfaced mostly filling the space is great. Loose stuff is not so good since it both settles and if your riser is isolated from the floor you might get some leakage from underneath.

I'm in the process of doing this right now. My joists are at 12" centers. Does that mean I have to cut every peace to width??? what a pain.

I just had to do just that, cut the batts down in width. I was using R-30 to fill a 2x8 stage. I found the easiest way to do it was to first cut through the kraft paper with large shears or scissors. Then slice through the rest of the insulaton with a really big, really sharp kitchen knife (12" long) worked great, was actually pretty easy to do. Just be sure to cut on top of some plywood.

Plus if you cut them down to about 11 inches wide, two of the narrow scraps will perfectly fill another cavity. No waste!

Good luck.

the easiest way to cut faced or unfaced insulation is to squeeze/smush it with a 2x4 that is lined up with your cut line. Just use a utility knife and run it along the 2x4 and it cuts like butter. If it's faced, keep the face down. One pass with a moderately sharp knife and you have a perfect cut.