#1873479 - 01/15/08 06:06 PM
DIY LArge Room - Spray-On Cellulose Insulation- Work?
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dennisc
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Registered: 03/22/06
Posts: 12
Loc: Knoxville, TN
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Ethan,
>
> I am trying to help my church with our awful sounding youth building. It
> is a basic box of about 115 feet long by ~50 feet wide and 18 feet - 20
> feet tall ceiling (roof is slanted). There is a stage at one of the short
> ends about 3 feet off the floor which is only about 30 feet wide x ~15
> feet deep, such that two small storage rooms are on either side. All four
> walls of the interior of this box are covered with architectural wood
> panels with the exception that one of the 90 foot long walls has all glass
> from floor to 6 feet with the wood panels above.
>
> There are some 4'x8' acoustic panels hanging from the ceiling. Other than
> that, nothing. Floor is single layer carpet over concrete. This room
> sounds SO bad. Feedback on stage, booming bass, etc.
>
> We can not afford commercial treatment. My idea is to do the following
> using cellulose insulation that is ~3 lbs/cu.ft. density and is typically
> either blown loose in an attic or is sprayed into newly framed walls in a
> mixture that sticks and fills the cavity solid before drywall is applied:
>
> Here's a link of one brand:
> http://www.insultechnology.com/cellulose_insulation.html
>
> For Bass Traping we could frame-out the six corners of the room floor to
> ceiling with 1x2 or 2x4 edges such that when we sprayed the cellulose into
> the corner it forms a triangle, much like a "tri-trap" type thing. Then
> we could cover this with cloth.
>
> For absortion on the wooden walls we could "frame" what looks like a wall
> section on the existing wall, then spray in the cellulose and cover with
> cloth.
>
> What do you think of this idea?
>
> How deep should the wall frames be?
>
> The application method typically relies upon a scraping device which uses
> the studs in a typical wall as resting points for the scraper which
> results in the cavities being perfrectly full/level with the stud
> dimensions. The link above shows this pretty well. Do you see the studs inside our wall-on-the-wall as a
> problem?
>
> I realize there would likely be more benefit if in the bass area if the
> wall-on-the-wall were not touching the wall, but I am blending three
> objectives: treatment, cost, DIY process that is doable by volunteers.
>
> I also think that we could augment the existing acoustic panels hanging up
> by layering some 703/705 batts on the top side.
>
> Thoughts?
>
> Thanks so much,
> Dennis Corley
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#1873519 - 01/15/08 07:36 PM
Re: DIY LArge Room - Spray-On Cellulose Insulation- Work?
[Re: dennisc]
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Rod Gervais
Senior Member
Registered: 10/08/03
Posts: 497
Loc: Central Village, CT
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I don't know about this approach - I have never seen reported results for this material used in this manner - and (based on what hands on experience I've had with it) I don't think it's really the right material to get the desired result.
You would be much better off sticking with what is tried - true and tested.
Rod
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#1873890 - 01/16/08 10:15 AM
Re: DIY LArge Room - Spray-On Cellulose Insulation- Work?
[Re: Rod Gervais]
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Ethan Winer
MP Hall of Fame Member
Registered: 06/12/00
Posts: 5383
Loc: New Milford, CT, USA
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Dennis,
I agree with Rod's assessment. If a material manufacturer doesn't offer absorption data in third octave bands, that alone tells you something.
--Ethan
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#1873905 - 01/16/08 10:35 AM
Re: DIY LArge Room - Spray-On Cellulose Insulation- Work?
[Re: Ethan Winer]
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dennisc
Member
Registered: 03/22/06
Posts: 12
Loc: Knoxville, TN
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Rod/Ethan,
I guess I am a little surprised at your responses. Here is why: In my readings on Ethan's sites about acoustics and OC703/705 etc. I have seen references like:
"When assessing rigid fiberglass, it is important to know its density so you can compare equivalent products. Owens-Corning 703 has a density of about three pounds per cubic foot (45 kilograms per cubic meter), and 705 is about six pounds per cubic foot (90 kilograms per cubic meter). Therefore, products from other companies that have a similar density will have similar absorption characteristics at the same frequencies. Note that some companies call their products mineral wool, mineral fiber, or rock wool, but acoustically they are equivalent to fiberglass."
From this I would infer that another insulation product, in this case cellulose which looks very similar to mineral wool, with a similar density per cubic foot would behave simlarly to fiberglass insulation, have similar absorption characteristics.
What I am missing or where is my thinking going astray?
Thanks,
Dennis
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#1874366 - 01/17/08 02:09 AM
Re: DIY LArge Room - Spray-On Cellulose Insulation- Work?
[Re: dennisc]
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Rod Gervais
Senior Member
Registered: 10/08/03
Posts: 497
Loc: Central Village, CT
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What you are missing is that you then began to add things to our list.......
You are specifically told to look at mineral wool - fiberglass - rockwool (which mean fiberglass or slag glass) and suddenly you pop up with something of totally different nature.
We did not say that everything in the world that has those same densities will give the same value.
I can find solid plastics that are 3pcf - but they won't work at all - the same goes for rigid foam insulation.
I hope that helped to put you on the right track.
One thing I do know for a fact - is that the spray on insulation companies performed their testing in such a manner that they got much better numbers for isolation (from an STC perspective) than what was acheived in the test data published in IR-761...... which I why I won't even allow them to bid on my projects.
Sincerely,
Rod
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#1874945 - 01/17/08 07:34 PM
Re: DIY LArge Room - Spray-On Cellulose Insulation- Work?
[Re: Rod Gervais]
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dennisc
Member
Registered: 03/22/06
Posts: 12
Loc: Knoxville, TN
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Rod,
Thank you for the clarification. I hope you weren't offended by my clarifying question. I was thinking that the cellulose and roockwool looked similar but that was a bad assumption. It also appears you have had some interaction with the cellulose situation. I appreciate your sharing your experience.
Thanks,
Dennis
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