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Title: Textured paint for sound absorption or defusion.
Post by: Gary Creely on November 14, 2010, 02:51:55 PM

I am woking with a church that is building a multi purpose space and really would like to drywall the ceiling. Is there any sort of textured paint product out there that could give the ceiling a NRC .60 or even just improve on the drywall?

I am looking to reduce the reverberation.

Title: Re: Textured paint for sound absorption or defusion.
Post by: Brad Weber on November 14, 2010, 10:36:04 PM

There are spray-on products that are often used for absorption, however you're talking 1", 2" or even thicker products applied by specially trained installers and not just a standard paint product.

NRC is simply the average of the 250Hz, 500Hz, 1000Hz and 2000Hz absorption coefficients, which makes it of relatively little value in defining the actual acoustical properties. I suggest avoiding looking at NRC numbers and instead make sure that any products uses actually address the appropriate frequencies.  And any diffusion offered by textured paint would likely be limited to very high frequencies.

Title: Re: Textured paint for sound absorption or defusion.
Post by: Gary Creely on November 14, 2010, 11:05:53 PM

Thanks Brad, that confirms what I was thinking. Just trying to figure out the most cost effective way to tame this room, and I am leaning more towards panels.

Title: Re: Textured paint for sound absorption or defusion.
Post by: Brad Weber on November 15, 2010, 07:27:41 AM

Especially when being applied in a space where you have a clear floor space and don't have to worry about existing finishes, the spray-on ceiling treatments can be a very cost effective option.  These materials can also provide additional thermal insulation and can usually be tinted different colors, which may save costs in other areas.

However, typically selecting the best acoustical treatments is based on looking at not just reverberation but other acoustical issues such as room modes and discrete reflections as well as functional issues such as congregational interaction and the sound system.  So there are typically factors other than simply the effect on reverberation time that lead to particular choices in the materials used and their location.

Title: Re: Textured paint for sound absorption or defusion.
Post by: Brian Ehlers on November 15, 2010, 12:52:50 PM

Gary, whatever you decide, don't let anyone talk you out of doing something.  My church built a multi-purpose room (for gatherings, not sports).  I'm kicking myself for not reviewing the architect's plans and saying something about the application of drywall not only on every wall but also on the vaulted ceiling.  The room is irregular enough that there are no major problems with modes or slap echo.  But the room met with immediate complaints regarding the noise level of hundreds of conversations.  We have applied thick, absorptive, acoustic panels to some of the wall surfaces, but the ceiling remains bare sheetrock.  The panels helped, but the room is still way too live.

Title: Re: Textured paint for sound absorption or defusion.
Post by: Brad Weber on November 15, 2010, 03:34:25 PM

A common thing to overlook in many multipurpose spaces is simply the surface area involved.  Look at the square footage of the available ceiling surface versus the square footage of the available wall surfaces.  In some cases it can take a lot of treatment on a smaller square footage of wall surface to provide the same absorption as would have been provided by something on the larger ceiling surface area.  So when someone changes a ceiling from acoustical tile to sheetrock and plans to make up for it in terms of overall absorption by treating the walls, they may end up with a lot of absorptive treatment on a lot of wall surface.  And that's just looking at the difference in overall absorption in the space.

Title: Re: Textured paint for sound absorption or defusion.
Post by: Arnold B. Krueger on November 15, 2010, 04:06:11 PM

Quote:

So when someone changes a ceiling from acoustical tile to sheetrock and plans to make up for it in terms of overall absorption by treating the walls, they may end up with a lot of absorptive treatment on a lot of wall surface.  And that's just looking at the difference in overall absorption in the space.

Under all this is economics. Acoustical ceiling tile usually has a low cost per square feet, while wall treatments are usually far more costly.

Title: Re: Textured paint for sound absorption or defusion.
Post by: Gary Creely on November 17, 2010, 08:58:23 AM

Brad Weber wrote on Mon, 15 November 2010 15:34

A common thing to overlook in many multipurpose spaces is simply the surface area involved.  Look at the square footage of the available ceiling surface versus the square footage of the available wall surfaces.  In some cases it can take a lot of treatment on a smaller square footage of wall surface to provide the same absorption as would have been provided by something on the larger ceiling surface area.  So when someone changes a ceiling from acoustical tile to sheetrock and plans to make up for it in terms of overall absorption by treating the walls, they may end up with a lot of absorptive treatment on a lot of wall surface.  And that's just looking at the difference in overall absorption in the space.

As with most church project there are indeed other factors. For instance there are some strong negative opinions on the durability of drop ceiling in a gym among the leadership.

I already have a solid ring of treatment going around the room between 4 and 8 feet. I am more concerned about the vertical energy. If I did panels I would put them straight onto the ceiling.

Brad: What is the name of some of these spray on products.

Title: Re: Textured paint for sound absorption or defusion.
Post by: Brad Weber on November 17, 2010, 09:30:58 AM

International Cellulose offers several different products based on the specific balance of acoustical absorption, durability, thermal insulation, light reflectance, installation conditions, etc. involved, http://www.ada-noisesolutions.com/products.html.  They can work with you to help assess which specific product would be best for your application.  Sonakrete is another option, http://www.sonakrete.com/index.html, and this is one I have heard of but am not personally familiar with, http://www.monoglass.com/a-noise-reduc.html.