1" ductboard with foil back/should I remove?

[John White]

Marc,

I believe the problem with leaving the foil/fsk on the duct board when "stacking" the panels is not knowing exactly how the material as such will perform. Certainly there will be greater reflection at some and multiple frequencies.

It's really not difficult to peel away the scrim if you want to. Yes, you will lose some of the fiberglass as it is glued to the kraft paper, but it shouldn't be significant. Better yet is you can use the duct board only as the faces of your panels/traps (in conjunction or not with spray glued fabric or whatever) and use less expensive insulation as the meat of the unit. I realize you say you have "quite a lot", but not really sure to what the equates.

[LSP]

Originally Posted by John White

Marc,

I believe the problem with leaving the foil/fsk on the duct board when "stacking" the panels is not knowing exactly how the material as such will perform. Certainly there will be greater reflection at some and multiple frequencies.

It's really not difficult to peel away the scrim if you want to. Yes, you will lose some of the fiberglass as it is glued to the kraft paper, but it shouldn't be significant. Better yet is you can use the duct board only as the faces of your panels/traps (in conjunction or not with spray glued fabric or whatever) and use less expensive insulation as the meat of the unit. I realize you say you have "quite a lot", but not really sure to what the equates.

The "quite a lot" translated into 10, four inch thick traps, WITH the foil left on all of them. If I peeled off the foil, I may have to use more panels to make sure I stay at least 4" thick.

What "less expensive" material did you have in mind?

[John White]

Just about any insulation is less expensive than duct board per cubic area. As panels get thicker, the cost per unit goes down relative to the area. In addition, duct board has both the fsk and the duct liner on the opposite side. The same applies to regular batt insulation. Kraft facing is quite a bit more money than unfaced batts. Likewise for batt insulation, cubic area has a similar price relationship. For example; 10 square feet of 12 inch R38 is of coarse more expensive than 10 square feet of 6" R19, but no where near double.

Since you already have the duct board, I guess it doesn't really matter. Sorry for the confusion subsequently.

If you have to use more than 4" then use more. *Why not use more? However, removing the foil firmly and quickly should yield decent results.

[Jamman]

Hey LSP -

I asked a similar question a while back in this thread:

To FRK or not to FRK - That's my question.

You might want to scope out what people said there... Ethan (and others) provided a nice response to my question that might help with yours.

-Jamman

[LSP]

Originally Posted by Jamman

Hey LSP -

I asked a similar question a while back in this thread:

To FRK or not to FRK - That's my question.

You might want to scope out what people said there... Ethan (and others) provided a nice response to my question that might help with yours.

-Jamman

Thanks, just saw your link... I'll check it out.

[GIK Acoustics]

I would peel it off. Unfortunately, some manufacturer's like CertainTeed's bonding is insanely strong and makes peeling the foil off extensively difficult. Much more difficult than it is on OC703.