How many inches does fire drywall need to be from wall out on ceiling?

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    It's not clear what you're asking here. What gave you the impression that there's a required gap? – isherwood Jan 14 '16 at 20:35
  • I think i understand now. At one time in my area garage ceilings only needed to be rocked out maybe 8 or 10 feet from common walls with an attached dwelling. Is that the question? – isherwood Jan 16 '16 at 0:21
  • If he's talking about firewall in a garage - every local code is different. In my area, the entire ceiling, adjoining heated wall, plus a double layer, between adjoining attic space, is required. But like you said - the question really isn't that clear. – tahwos Jan 16 '16 at 2:11

Drywall (or sheetrock) on the ceiling is installed tight against the wall framing with hopefully less than 1/2" gap. Any gap larger than this removes the support you'll provide later.

The drywall installed on the walls is next installed on the top half of the wall pressed against the ceiling drywall which gives it support. Then the bottom half of the drywall on the walls is install tight against the board above with joints offset. Any gap at the floor is covered with trim.

  • It's a myth that the wall panels support the ceiling panels. If that was true, the sheets in the field would also need support. The primary reason is that it's more difficult to get good edge fitment on ceilings, so the larger gaps are covered by the wall panels. – isherwood Jan 14 '16 at 20:36
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    There's "gives it support" and "the only thing holding it up", I'm referring to the former. There are countless examples of drywall ceilings collapsing, and I've personally witnessed some where the only thing preventing a full collapse were the sides and the wiring to a light fixture. E.g. nachi.org/forum/attachments/f18/… – BMitch Jan 14 '16 at 20:42
  • Another minor reason the top panels are installed on the walls first is that it's easier to fiddle with the bottom panels (mark, cut, hold up to the wall) than it is to do the same thing while holding the top panels up in the air. – Craig Jan 14 '16 at 21:42

Fire rated drywall, if the ceiling is required to have this installed, must be installed for the entire ceiling of the given room. This helps provide a means of slowing a fire from reaching the room above it. Make sure you understand, by no means will this stop a fire from advancing it will only slow its progress in order to give occupants more time to exit the building.

  • Eddie, how does this answer the OP's question about whether (and how much ) a gap is required between the edge of the drywall on the ceiling, and the wall? – Craig Jan 14 '16 at 23:41
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    I read his question as how far out from the wall does fire drywall need to be installed. Since the wording of his question is somewhat unclear and this interpretation hasn't been answered yet I answered it. – Eddie Studer Jan 14 '16 at 23:48
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    His question doesn't mention a gap in any way – Eddie Studer Jan 14 '16 at 23:49
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    The OP is asking how many inches fire drywall.... Okay, I see. It MIGHT be the case that the OP is asking if he can put a thin strip of fire-rated drywall around the edges of the room and fill in with "regular" drywall. The thing is that "fire rated" is basically a matter of the drywall being 5/8" thick or thicker, so the question doesn't feel right in that sense because you'd end up with two different thicknesses of drywall on your ceiling... – Craig Jan 15 '16 at 0:02
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    They make fire rated drywall and yes it is 5/8" thick, but still, all house plans I have ever seen in my 17 years in construction have never had a ceiling or Fire Marshal allow a thin ring of fire rated drywall around the edge of the room. It is either the whole ceiling or its not required. The logic behind a thin strip doesn't make sense anyways. A fire is not going to halt or be slowed just because it can't get past a 2 foot wide or so barrier. It will find the weak point and make its way through. The OP clearly needs to edit his question in order for it to be answered properly. – Eddie Studer Jan 15 '16 at 0:18

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