A friend of mine in MI says his AHJ wants double 5/8" type X drywall on the ceiling of his garage with a bedroom above.
Does anyone know of an equal thinner alternative? Space is limited in his specific situation on the remodel.
Thanks in advance.
Is this for a single family home? Can’t say I have ever heard of that for a single family structure. You can see if Type C wallboard or another higher fire resistant board is available in your area.
Non-combustible materials… (aka. concrete)… BUT… if the AHJ want’s 2 sheets of X, there may be no other choice than 2 sheets of X. He may need to change the plans to a “game room” vs a “bedroom”.
Thanks, guys.
He’s checking into the type “C” and other commercial and industrial possibilities.
Just curious Larry, why does an extra layer of sheetrock affect the plans?
Must be a critical clearance issue to worry about 5/8"
My experience is to cover over the butt joints… tape & mudd alone isn’t good enough, especially with vapor/fumes. Just think how often you see failed T&M on joints.
That’s why best practice is to caulk the joints and fasteners before, or in place of, tape and mud. Though few do it that way.
Yes but that doesn’t answer the question.
Frank has it. The remodel is really tight in certain areas.
I’m just looking for something to equal 2 layers of 5/8" type X drywall but is not as thick…that is it.
Thanks all. 
Larry, if the intent is to achieve a 1-hour rated construction, there are multiple ways of achieving it without the use of two layers of 5/8" gypsum.
Look at the ceiling and floor construction here and chose the 1-hour protection that applies and required.
Thank you, Marcel.
It was good talking to you.
You are welcome Larry, and glad to help. 
If you’re looking for sound separation between a garage and upstairs bedroom, check out QuitetRock.
It’s more expensive, but you can get the characteristics of multiple layers of drywall in a single sheet, assuming it’s installed correctly.