Thread: OSB at Garage Ceiling?

OSB at garage walls and ceilings with no gypsum board? Acceptable or not?

Paperbacking on drywall, yes it is already noted on report.

Opinions welcome.

rick

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Originally Posted by Rick Hurst

OSB at garage walls and ceilings with no gypsum board? Acceptable or not?

Paper backing on drywall, yes it is already noted on report.

Opinions welcome.

rick

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Bump.

Rick,

As far as I got Dallas County TX currently uses ( with some exceptions) 2006 Residential Code.

My money would be not allowed as OSB is not a fire rated material.
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Nope......at least not here. This came up a couple of weeks ago for me on a garage addition. Building inspector told me I could put the drywall on the wall between the house and garage all the way to the roof sheathing and then install the plywood/osb over the drywall (on the wall), ceiling could then be left unfinished or plywood/osb installed.

Must have ceiling and common walls with gypsum board for separation.

Funny how we have answers to this but Rick didn't say what's above the garage or on the other side of the walls. And no, I'm not in the habit of assuming things.

Eric, only attic space above the garage and a family room opposite the front garage wall.

Rick

Originally Posted by Rick Hurst

Eric, only attic space above the garage and a family room opposite the front garage wall.

Rick

Wall kindling. I write it up and explain it to my clients all of the time.

Many times (many) cars are pulled into garage only to catch fire after everyone has gone into the home.

Originally Posted by Rick Hurst

OSB at garage walls and ceilings with no gypsum board? Acceptable or not?

Paperbacking on drywall, yes it is already noted on report.

Opinions welcome.

rick

Interesting question really. I think that OSB would be more of a fire resistive material than drywall, even if it was 5/8 fire stop. But the seams between the sheets, whether they are drywall or OSB, needs to be taped on the common walls and ceiling with common attic like Jim L pointed out. So the tapping is the real issue. And since nobody tapes OSB, drywall is the product to use.


If the garage is detached from the house then it doesn't matter what you do to the walls and ceiling.

Originally Posted by Jeff Langhorn

Interesting question really. I think that OSB would be more of a fire resistive material than drywall, even if it was 5/8 fire stop. But the seams between the sheets, whether they are drywall or OSB, needs to be taped on the common walls and ceiling with common attic like Jim L pointed out. So the tapping is the real issue. And since nobody tapes OSB, drywall is the product to use.


If the garage is detached from the house then it doesn't matter what you do to the walls and ceiling.

I'm not sure why you would think OSB would be more fire resistive than gypsum, but here are some flame spread ratings for the two:

gypsum is Class I with a flame spread of 10-15
OSB is Class III with a flame spread of 150

Most solid woods would be better than OSB at flame spread.

Originally Posted by Jeff Langhorn

Interesting question really. I think that OSB would be more of a fire resistive material than drywall, even if it was 5/8 fire stop. But the seams between the sheets, whether they are drywall or OSB, needs to be taped on the common walls and ceiling with common attic like Jim L pointed out. So the tapping is the real issue. And since nobody tapes OSB, drywall is the product to use.


If the garage is detached from the house then it doesn't matter what you do to the walls and ceiling.

After posting that I though OSB was a better fire stop than drywall I searched the web and found the opposite. OSB will go up ln flames like a roman candle. Drywall needs to be used on common walls and ceilings, all seams and holes need to be taped.

Originally Posted by JB Thompson

Many times (many) cars are pulled into garage only to catch fire after everyone has gone into the home.

I'll be Rick could expound a little for us on that subject

Still another question --- if the garage wall against the conditioned area of the home were drywalled and taped, from garage floor to the roof line whereby the attic over the conditioned area was sealed off from the garage, why would some of you still be expecting the underside or the garage's roof framing to have a sealed surface?

Sorry to be anal (something I'm quite proficient at), but I think that there has been a tendency to answer Rick's question without a full understanding of the conditions. A bad habit for any inspector.

Originally Posted by Eric Barker

Still another question --- if the garage wall against the conditioned area of the home were drywalled and taped, from garage floor to the roof line whereby the attic over the conditioned area was sealed off from the garage, why would some of you still be expecting the underside or the garage's roof framing to have a sealed surface?

Sorry to be anal (something I'm quite proficient at), but I think that there has been a tendency to answer Rick's question without a full understanding of the conditions. A bad habit for any inspector.

That is the point of my question, it was not done as such.

rick

Originally Posted by Eric Barker

Still another question --- if the garage wall against the conditioned area of the home were drywalled and taped, from garage floor to the roof line whereby the attic over the conditioned area was sealed off from the garage, why would some of you still be expecting the underside or the garage's roof framing to have a sealed surface?

Sorry to be anal (something I'm quite proficient at), but I think that there has been a tendency to answer Rick's question without a full understanding of the conditions. A bad habit for any inspector.

I re-read the original post. Not sure I'm following.

If you are saying that the sheetrock covers the common wall of the garage and the living space (not a bedroom) and extends all of the way to the roof rafters effectively sealing off the home and there are no poke-thrus or holes. Then this is considered a firewall and is OK.

I don't believe there is a requirement for the garage ceiling to be "sealed" if there is no common attic.

I'll go double-check the codes.

I know in Dallas, commerical wood construction such as a cockloft, parallel-chord trussed area between floors or attic space is supposed to be firewalled every 1000 sqft.

Here is the separation vs. material requirement in the 2009 IRC

R302.6 Dwelling/garage fire separation.
The garage shall be separated as required by Table R302.6. Openings in garage walls shall comply with Section R302.5. This provision does not apply to garage walls that are perpendicular to the adjacent dwelling unit wall.

TABLE R302.6
DWELLING/GARAGE SEPARATION

From the residence and attics: Not less than 1/2-inch gypsum board or equivalent applied to the garage side


Is this what you're saying/asking? I'm fairly thick-headed and like Eric said, I'm sometimes anal. Not sure which is better.

If the fire separation wall is in place between the house and the garage, then they can put up the OSB over everything else. Including the fire separation wall, covering the sheetrock.

How's this for a garage ceiling! This was a drive in under the home garage at that!! I found this on an inspection yesterday.

Originally Posted by Jim Luttrall

Must have ceiling and common walls with gypsum board for separation.

Gypsum board is not required to be on the ceiling if this is done:

Originally Posted by chris mcintyre

Building inspector told me I could put the drywall on the wall between the house and garage all the way to the roof sheathing

Do that and you can leave the garage ceiling open.

Originally Posted by Scott Patterson

How's this for a garage ceiling! This was a drive in under the home garage at that!! I found this on an inspection yesterday.

Unfortunately, I believe it wouldn't dawn on most people until you mention it at the inspection. Then the little light comes on

I would also call out the exposed Kraft Faced insulation as being a fire hazard. It needs covered (by something with a better fire rating than plastic sheeting). Burns like gas!

Originally Posted by Rick Hurst

OSB at garage walls and ceilings with no gypsum board? Acceptable or not?

Paperbacking on drywall, yes it is already noted on report.

Opinions welcome.

rick

Originally Posted by Larry Morrison

I would also call out the exposed Kraft Faced insulation as being a fire hazard. It needs covered (by something with a better fire rating than plastic sheeting). Burns like gas!

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