# Is drywall required under tongue & groove ceiling?



## Msradell (Sep 1, 2011)

There are a lot of variables that could affect the answer to your question. Your best bet would be used to discuss the issue with the building inspector you are working with. He's more familiar with what codes are used in your area and how they are interpreted locally.


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## Mingledtrash (Nov 27, 2015)

Msradell said:


> There are a lot of variables that could affect the answer to your question. Your best bet would be used to discuss the issue with the building inspector you are working with. He's more familiar with what codes are used in your area and how they are interpreted locally.


Msradell is correct talk to your local building inspector. You will have to replace and patch the gypsum board to get proper fire rating. keep in mind you have a bedroom directly above one of the highest fire risk areas in your house.


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## oh'mike (Sep 18, 2009)

In any area that I have worked in, drywall was required behind a flammable surface--

So my guess is yes---fire taped drywall will be required.


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## ryansdiydad (Aug 16, 2015)

3/4" T&G has a sufficient fire rating to be used in place of drywall in areas where a minimum fire rating is required... like in my case when it came to covering foam board insulation... 

That has little to do with your situation just something I learned as I was exploring my options where I used the foam boards to insulate a T&G cathedral ceiling... 

With a kitchen below a bedroom I would do the drywall.. with fire taping as Oh'mike suggested..


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## Gary in WA (Mar 11, 2009)

Under the IRC; 1/4" thick is the minimum without drywall; http://publicecodes.cyberregs.com/icod/irc/2009/icod_irc_2009_7_sec002_par017.htm

You are under the IBC; http://www.cmdgroup.com/building-codes/arizona/
Enjoy; http://publicecodes.cyberregs.com/icod/ibc/index.htm

Gary


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## Mingledtrash (Nov 27, 2015)

Gary in WA said:


> Under the IRC; 1/4" thick is the minimum without drywall; http://publicecodes.cyberregs.com/icod/irc/2009/icod_irc_2009_7_sec002_par017.htm
> 
> You are under the IBC; http://www.cmdgroup.com/building-codes/arizona/
> Enjoy; http://publicecodes.cyberregs.com/icod/ibc/index.htm
> ...


I think you may have missed the bedroom above.

202 Definitions
SLEEPING UNIT.- A room or space in which people sleep, which can
also include permanent provisions for living, eating, and either 
sanitation or kitchen facilities but not both. Such rooms and spaces 
that are also part of a dwelling unit are not sleeping units.

420.3 Horizontal seperation.
Floor assemblies seperating dwelling units in the same buildings, 
floor assemblies seperating sleeping units in the same building and 
floor assemblies separating dwelling or sleeping units from other 
occupancies contiguous to them in the same builing shall be 
constructed as horzontal assemblies in accordance with section 711

711.2.4 Fire-resistance rating.
The fire-resistance rating of horizontal assemblies shall comply with 
Sections 711.2.4.1 through 711.2.4.6 but shall be not less than that 
required by the building type of construction.

711.2.4.3 Dwelling units and sleeping units.
Horizontal assemblies serving as dwelling or sleeping unit seperations in accordance with Section 420.3 *shall be not less than 1-hour fire-resistance-rated *
construction.


after all of that you go to Table 721.1(3) item 13. specifically 13-1.4 be sure to read foot notes _m_, _n_
I cant post the table here but it calls out 19/32 wood structural panel t&g on top(a few other options are available this is the most common) and 1/2" type-x gypsum (among a few other plaster options) to get your 1 hour fire rating. 

http://codes.iccsafe.org/app/book/content/2015-I-Codes/2015 IBC HTML/Chapter 7.html


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## firehawkmph (Dec 12, 2009)

Irregardless of whether or not you can get away without it, it would make for a better installation with drywall under it. Tape the drywall to seal it up against air infiltration. The T&G wood by itself has a tendency to shrink a bit across the width over time. Sometimes you'll end up with a slight gap or loose fitting tongue and groove. Without the drywall, you may get some cold air coming through. 
Mike Hawkins:smile:


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## ZZZZZ (Oct 1, 2014)

Thanks for the feedback guys, I'll go ahead and put up the drywall. I will be getting to work on this sometime next month.

Just to clarify, I understand that I would need to tape and mud the drywall joints. (No need to worry about the nail or screw heads, right?) Should the drywall be primed for some reason?


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## oh'mike (Sep 18, 2009)

No need to prime---just paper tape --this will stop drafts---


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