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small town
Finishing garage ceiling 2 part question

I have a 30'x32'garage that is attached to my home only by a roof.
The garage is constructed with commercial 2x4 trusses 16" on center. I am planning on all the wiring to be inside exposed conduit installed after all my walls are completed. I will use it for parking and a workshop area

Although there is no code I beleive that I should install 5/8 fire resistant sheetrock at least on the ceiling. Since the trusses are 2x4 I thought I should install a plastic vapor barrier then sheetrock and rollout unfaced 4" deep insulation between the trusses. I would then add more insulation perpindicular to the first, but am not sure what happens when I bump up against the truss "X" framing? Do I cut it and snug it in as much as possible?

My second part is do I need to install strapping to the garage ceiling? I was thinking I had to and thought 12" about on center. A rescent vist to my local big box was quite a surprise when I priced 1x3 strapping. I have searched the web: some say strap others are just screwing the sheetrock to the bottom of the trusses.
I wonder if I will have enough nailing surface for sheetrock without strapping?

Appreciate any information.
Thanks in advance.

ed21
Re: Finishing garage ceiling 2 part question

The fire rated gyp board should be against the house, only 1/2" is usually required. Most 5/8" gyp board sold is fire rated. It's not required on the ceiling if no living space above. Local codes may vary.
Strapping is not required. Regular 1/2" or high strength board can be used. 5/8" works too, just heavier and costs more. Use screws, not nails.
The insulation installation method sounds right.

A. Spruce
Re: Finishing garage ceiling 2 part question

I concur with most of what Ed suggests, except the sheetrock - sort of.

Code requires a fire rating between the garage and attached living space, which is met by the 5/8 rock. Also, 5/8 rock is more resistant to sagging than even reinforce 1/2" rock is, so I'd recommend sticking with 5/8 on the ceiling. Using it on the house facing wall would not be a bad idea either, though with the space between the house and garage it's not a necessity. All other walls can be 1/2", no problem. If you're going to be hard on the walls, then I'd suggest sticking with 5/8 throughout. Definitely use screws to hang the rock, it will prevent nail pops in the future and gives a much stronger hold than nails. A few nails to tack a sheet into place is perfectly acceptable.

I'd also recommend either running the wiring before the drywall to save the time and expense of all that conduit OR run the conduit in the walls before installing the drywall for a much cleaner look and feel. With the conduit in the wall you can still change your wiring as requirements dictate. You can also run additional conduit on the surface if necessary, but it would be minimized. Again, this is more for aesthetics than anything else.

small town
Re: Finishing garage ceiling 2 part question

Thanks to both of you for the information. Now if the heat and humidity would just ease up a little maybe I could get something done!

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