# Spray-On Fiberglass Drop Ceiling



## MaxS (Aug 9, 2010)

Is this a common acoustic treatment for theatre spaces? This particular venue has a steel mesh drop ceiling with several layers of spray-on fiberglass. It is my understanding that the room was deemed "too live" acoustically, and this was used as a solution during a renovation. However, the space is now completely dead from the stage to the house. Sound reinforcement becomes straight amplification because nothing projects. However, from the house to the stage, sound echoes erratically.

If this type of treatment is intended for sound dampening and absorption, is there a logical reason why it was chosen? Or was this a matter of "The hell with it, let's let the general architect fix the 'loudness problem' in the theatre"?


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## llecount (Aug 10, 2010)

You sure that's fiberglass? Looks exactly similar to the asbestos acoustic treatment we have in one of our large convention rooms on campus.


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## sk8rsdad (Aug 10, 2010)

I suspect it is K-13 or Sonaspray, which is a cellulose fibre product from International Cellulose Corporation. If the treatment was done after 1980 it is highly unlikely that they used an asbestos product.


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## TheLightmaster (Sep 26, 2010)

sk8rsdad said:


> I suspect it is K-13 or Sonaspray, which is a cellulose fibre product from International Cellulose Corporation. If the treatment was done after 1980 it is highly unlikely that they used an asbestos product.


Looks like Sonaspray over lath and plaster.


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## museav (Sep 27, 2010)

I agree as far as the material, however I question covering the entire ceiling as ceilings are often used to provide some beneficial early reflections to the seating. That also represents a huge area directly opposite what is probably already the most absorptive surface, the audience, meaning lots of added absorption but perhaps not most effectively applied. If that is all that was done acoustically you may end up with a room that makes the audience feel separated from the stage and one another, relies heavily on the sound system for any live events and yet still has reflection problems from some of the wall surfaces.

Do you know if anybody made any measurements of the existing conditions or performed any analysis before deciding what was an appropriate approach?


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