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Knauf with foil backing or no backing?
Old 22nd October 2017
  #1
Knauf with foil backing or no backing?

Wanting to build some early reflection acoustic panels using Knauf rigid insulation. The guy at the store ask if I wanted foil backing. Anyone know? I assume foil would backing would not be the way to go but I really have no idea.
Old 22nd October 2017
  #2
Gear Guru
No Harm

Presuming a reasonable thickness HF will not get to the Foil if it is at the back. In which case it should have a slightly beneficial effect at lower frequencies.
DD
Old 25th October 2017
  #3
Thank you DanDan. Would two inch be enough or 4?
Old 25th October 2017
  #4
Gear Guru
Quadruple

You are welcome. I often quip, whatever amount of treatment you have in your mind, multiply it by four. And so it is here. You ask about 2". We often recommend 4" fibre plus a 4" airgap as a minimum worth while absorber.
DD
Old 2nd September 2020
  #5
Do you think this stuff
https://www.knaufnorthamerica.com/en...d-plenum-liner
is as good as Owen Corning 703?
Old 2nd September 2020
  #6
Quote:
Originally Posted by pjarrett View Post
Do you think this stuff
https://www.knaufnorthamerica.com/en...d-plenum-liner
is as good as Owen Corning 703?
Rockboard 40 is the equivalent.
https://www.rockwool.com/siteassets/...20180718142515
Old 2nd September 2020
  #7
So the Rockboard 40 is better than Knauf Plenum or the same you think?
Old 2nd September 2020
  #8
Lives for gear
 
avare's Avatar
 

Quote:
Originally Posted by thethrillfactor View Post
This is a fun addition..Rockboard 40 is superior to 703.
Old 2nd September 2020
  #9
Well I had bought this Knauf Rigid plenum by mistake.

https://www.knaufnorthamerica.com/en...plenum-linernd

I just wondering if I can still use it. Its 2". If I put two together would it work as well as the Rockboard 40 you suggest?
Old 2nd September 2020
  #10
Lives for gear
 
Jason Foi's Avatar
 

Quote:
Originally Posted by pjarrett View Post
Do you think this stuff
https://www.knaufnorthamerica.com/en...d-plenum-liner
is as good as Owen Corning 703?
Thats duct liner, and WAY more expensive than regular rigid fiberglass if my memory serves me correctly. I would return/cancel your order and go with an alternative product. If still treating first reflection points i would opt for safe n sound @ 9" thick or fluffy fiber at 12" thick..
Old 2nd September 2020
  #11
Thank you for the suggestion. I can't really go that thick but it sounds like the the stuff I got I'll try to return.
Old 2nd September 2020
  #12
Lives for gear
 
avare's Avatar
 

Quote:
Originally Posted by pjarrett View Post
Well I had bought this Knauf Rigid plenum by mistake.

https://www.knaufnorthamerica.com/en...plenum-linernd

I just wondering if I can still use it. Its 2". If I put two together would it work as well as the Rockboard 40 you suggest?
Not in any shape or form.
Old 2nd September 2020
  #13
Thank you Avare. If I can only go 4" will Knauf insulation Earthwool board be the thing to get?
Old 2nd September 2020
  #14
I can only get Rockboard 80. Is that as good as the 40?
Old 2nd September 2020
  #15
Lives for gear
 
Jason Foi's Avatar
 

Quote:
Originally Posted by pjarrett View Post
I can only get Rockboard 80. Is that as good as the 40?
Where do you live?
Old 2nd September 2020
  #16
Thanks Jason, I just found some Rockboard 40.
Old 2nd September 2020
  #17
Lives for gear
 
avare's Avatar
 

Quote:
Originally Posted by pjarrett View Post
Thank you Avare. If I can only go 4" will Knauf insulation Earthwool board be the thing to get?
Rockboard 40.
Old 2nd September 2020
  #18
Thank you Avare,
So what you are saying is Rockboard 40
is better than Knauf earthwool 3lb?
Old 2nd September 2020
  #19
Lives for gear
 
avare's Avatar
 

Quote:
Originally Posted by pjarrett View Post
Thank you Avare,
So what you are saying is Rockboard 40
is better than Knauf earthwool 3lb?
I replied to your generic Earthwool question with a specific material. What is not clear? Yes Rockboatd 40 at 1oo mm thickness is better than Earthwool 3 lb/ft³.
Old 2nd September 2020
  #20
Thank you again,
Sorry I just wanted to double check. And I very much appreciate your input.
Paul
Old 3rd September 2020
  #21
Is there any Knauf insulation board that can be an alternative to Rockboard 40 ?
Old 3rd September 2020
  #22
Lives for gear
 
avare's Avatar
 

Quote:
Originally Posted by pjarrett View Post
Is there any Knauf insulation board that can be an alternative to Rockboard 40 ?
What are you asking? You have consistently been"pushing" Knauf even after you posted that you found some Rockboard 40. Rockboard 40 is the best in 100 mm range. 703 is less than half as absorbent @ 125 Hz. I am awaiting a reply from Knauf about absorption coefficients of their products at greater than 50 mm thickness.

You can use anything you want.
Old 3rd September 2020
  #23
Thank you Avare,
Yes I was hoping to use a Knauf product because they don’t use formaldehyde . And because you suggested 40 Rockboard I was hoping Knauf might have something similar. When I bought the Knauf rigid plenum the salesman said that product was very good for absorption but I trust you’re expertise more.
Old 3rd September 2020
  #24
Lives for gear
 
avare's Avatar
 

vI just had a phone call with Knauff. The closest product is the 3.0 lb/ft³ Knauf Earthwool Insulation Board.
Attached Files
Old 3rd September 2020
  #25
Thank you very much Avare,
Very much appreciate it, Sir.
Old 4th September 2020
  #26
Lives for gear
 
Kyle P. Gushue's Avatar
Quote:
Originally Posted by avare View Post
vI just had a phone call with Knauff. The closest product is the 3.0 lb/ft³ Knauf Earthwool Insulation Board.
Thank you.
Old 4th September 2020
  #27
Lives for gear
 
avare's Avatar
 

Quote:
Originally Posted by Kyle P. Gushue View Post
Thank you.
You are welcome.
Attached Files
Old 4th September 2020
  #28
Lives for gear
 
Starlight's Avatar
 

Quote:
Originally Posted by avare View Post
vI just had a phone call with Knauff. The closest product is the 3.0 lb/ft³ Knauf Earthwool Insulation Board.
Andre, you are a star!
Old 9th September 2020
  #29
After looking around on this site and others it seems that Roxul Safe and Sound 3 inch might be better to use with a piece of the 2 inch knauf glass board in front?

Or would it be better to get 6 inch Safe and Sound for side wall reflections with a 3 inch air gap behind it?
Old 9th September 2020
  #30
Quote:
Originally Posted by pjarrett View Post
Or would it be better to get 6 inch Safe and Sound for side wall reflections with a 3 inch air gap behind it?
If you are thinking about going 9" deep, its better to go to a full fill then leaving a gap.
Attached Thumbnails
Knauf with foil backing or no backing?-screen-shot-2020-09-09-2.35.24-pm.jpg  
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