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If the MLV was not bonded to the joists, then there is no value in gluing the sheetrock to the MLV. Add extra screws if you like, but a standard screw pattern of 6 screws per joist will suffice. I know it is not part of your question, but RC-1 channel is a really cost effective way to add a lot of sound deadening to the ceiling in addition to the MLV, if it ...


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I am going to point out that I do not approve the additional layer of drywall for ceiling. I just answered a question here - Should I use 1/4" drywall to cover ceiling texture or imperfections? - that addresses my concerns with an extra layer of drywall on ceilings. I love doubleing up drywalls on wall (vs furring out) so I am definitely "liberal" ...


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Yes, both sets of screws are required. Two layers of gypsum board is generally used for two hour fire wall protection. The protection (and rating) comes from the proper installation, including proper nailing for both layers. If a fire develops and causes the top layer to fall, then the second layer would not have approved fastening to develop the two hour ...


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