Correct way to do OSB ceiling

[jeepnatv4life]

I am planning to hang osb from my ceiling attached to the trusses. I am going to run 2x4's to the bottom and attach the osb to that. My question is where should the moisture barrier be? I am going to have the insulation blown in september or so.

 

[larry4406]

Why the 2x4's attached to the trusses? Can't you secure the OSB directly to the trusses?

In the houses I build in northern VA and MD we screw drywall directly to the trusses which are 24" on center in most cases. We also blow in insulation on top of the drywall without any vapor barrier to R43. This is standard practice in this area.

Harrisonburg is maybe 2 hours south of me at most so I would think the above should apply to you.

 

[Falcon67]

If you don't use the vapor barrier (unless it's going to be continually heated/cooled I don't think it's totally necessary) be sure and caulk the seams between the sheets. That will stop air movement into the attic.

 

[stonesfan68]

You should make sure that the trusses are designed to handle the extra weight of the OSB.

 

[DougWil]

If you are going to have a heated, insulated, well lit garage OSB isn't the best choice for a ceiling.

The ideal is an air barrier (penetrations sealed) and a vapor barrier at the inside face of the ceiling (painted and all seams and joints sealed).

OSB is porous, soaks up a lot of paint sealing it and it's rough surface doesn't reflect light as well as a smooth surface.

 

[jeepnatv4life]

Why the 2x4's attached to the trusses? Can't you secure the OSB directly to the trusses?

In the houses I build in northern VA and MD we screw drywall directly to the trusses which are 24" on center in most cases. We also blow in insulation on top of the drywall without any vapor barrier to R43. This is standard practice in this area.

Harrisonburg is maybe 2 hours south of me at most so I would think the above should apply to you.

My pole barn is on 4 ft centers. I would have to rip sheets to use the trusses to nail to wouldnt I?

 

[jeepnatv4life]

If you are going to have a heated, insulated, well lit garage OSB isn't the best choice for a ceiling.

The ideal is an air barrier (penetrations sealed) and a vapor barrier at the inside face of the ceiling (painted and all seams and joints sealed).

OSB is porous, soaks up a lot of paint sealing it and it's rough surface doesn't reflect light as well as a smooth surface.

Osb I thought would be the easiest to work with vs metal. I was going to staple plastic to the bottom of the trusses then run the nailers/2x4's then osb..

 

[jeepnatv4life]

You should make sure that the trusses are designed to handle the extra weight of the OSB.

My Builder said that it could handle the loads

 

[DougWil]

Osb I thought would be the easiest to work with vs metal. I was going to staple plastic to the bottom of the trusses then run the nailers/2x4's then osb..

Then your OSB with absorb moisture from the warm room and with the vapor barrier on the backside will not allow that moisture to pass through.
Trapped with the nailers and that 1-1/2 air space.

Additionally, since the plastic isn't supported by the OSB (if I understand correctly) any insulation will be supported only by stapled plastic that eventually will sag and tear negating that vapor barrier.

If you paint that OSB, then you have created multiple vapor barriers which is never a good idea.
Unpainted OSB doesn't reflect light well and the rough surface holds dirt and dust.

The ideal is that any warm, moist air is kept inside the room, not walls, ceiling or attic. And if that level of moisture is a problem (tool rusting etc... use a dehumidifier.

 

[jeepnatv4life]

Then your OSB with absorb moisture from the warm room and with the vapor barrier on the backside will not allow that moisture to pass through.
Trapped with the nailers and that 1-1/2 air space.

Additionally, since the plastic isn't supported by the OSB (if I understand correctly) any insulation will be supported only by stapled plastic that eventually will sag and tear negating that vapor barrier.

If you paint that OSB, then you have created multiple vapor barriers which is never a good idea.
Unpainted OSB doesn't reflect light well and the rough surface holds dirt and dust.

The ideal is that any warm, moist air is kept inside the room, not walls, ceiling or attic. And if that level of moisture is a problem (tool rusting etc... use a dehumidifier.

I have no idea why I thought putting the nailers up was a good idea... I can just fasten the osb to the truss... ends and center

i plan to paint the OSB

i just ran to stoneburners and priced metal sheets It gonna run me roughly $875 for the metal with no hardware 1.97 a linear foot. Cut to whatever length SO I just did an est for 3x12.

OSB ceiling is gonna be $418 plus a couple gallons of paint and hardware..

My shop is 30x40

 

[Milton Shaw]

OSB needs to be supported at max 24" centers and even then you will have some sag. Might be a good idea to use the roofing clips between the sheets to keep the edges together. You will need 2x4's to support that OSB.

 

[jeepnatv4life]

OSB needs to be supported at max 24" centers and even then you will have some sag. Might be a good idea to use the roofing clips between the sheets to keep the edges together. You will need 2x4's to support that OSB.

for a 3/8 sheet??

 

[Blk88GT]

I sheeted my 40x50 with 1/2" plywood, walls and ceiling. 24" centers, no H clips. Vapor barrier on the backside and blown in insulation (R50) on top.

I used a framing nailer with 2.5" ring nails. It was a hell of a job.

1 coat of oil based primer and 2 coats of semi gloss white on top of it.

 

[koondog]

I did my ceiling with OSB about 12 years ago. 2 foot on center, sprayed it with white paint and used rolled insulation in the attic above. Garage is heated in the winter. I am still very happy with it.

 

[Falcon67]

OSB needs to be supported at max 24" centers and even then you will have some sag. Might be a good idea to use the roofing clips between the sheets to keep the edges together. You will need 2x4's to support that OSB.

Mine is on 24" center, 7/16" OSB, no sag. No discoloration, no moisture problems, didn't paint, plenty of light to work, only R13 in the ceiling, no vapor barrier. Did it all wrong, easy to heat and cool even when the roof deck is 160F. Place is nice and comfy year around

 

[barks]

The correct way to hang OSB on the ceiling is to use 5/8 gypsum board.

 

[DougWil]

Mine is on 24" center, 7/16" OSB, no sag. No discoloration, no moisture problems, didn't paint, plenty of light to work, only R13 in the ceiling, no vapor barrier. Did it all wrong, easy to heat and cool even when the roof deck is 160F. Place is nice and comfy year around

Yes you did, but you can get away with it in a moderate climate.

Where it is colder, the meter would be spinning with R13, moisture would be condensing and dripping in your attic space, creating black mold or freezing and causing ice dams.

 

[DougWil]

for a 3/8 sheet??

Yes, attached only at 3 points per sheet will be saggy, especially with time.

Put the nailers between and perpendicular to the trusses, flush with the bottom.

With the fire hazard, off gassing of formaldehyde, taping issues, etc.... suggest you just use sheetrock.

 

[Evilunclegrimace]

Yes, attached only at 3 points per sheet will be saggy, especially with time.

Put the nailers between and perpendicular to the trusses, flush with the bottom.

With the fire hazard, off gassing of formaldehyde, taping issues, etc.... suggest you just use sheetrock.

According to the SBA and the CPA the Formaldehyde emissions in OSB are nearly nonexistent.

 

[zendriver]

I just finished 2/3 my garage ceiling in 7/16 OSB (1/3 already done by previous owner.

looks fine and does not sag at all. I'll use kraft faced insulation.

IMO, I would not go any thinner than 7/16, which might sag. It is lighter than drywall anyway.

Rent a panel lift to do the job.

 

[ZRX61]

I don't think there is a correct way to do anything with the stuff, can't stand the way it looks.

 

[DougWil]

According to the SBA and the CPA the Formaldehyde emissions in OSB are nearly nonexistent.

Whatever is in the glue NEW OSB gives me a mild headache in confined areas.
Aged OSB doesn't.

 

[Falcon67]

Fwiw, we did not have any issues with outgassing. My wife can smell a trucker smoking a cig driving a cattle truck a half mile up the road. Maybe we were lucky, not sure.

 

[csp]

looks fine and does not sag at all

Are your framing members at 4' centers like the OP has?

 

[jeepnatv4life]

im gonna take my chances Im gonna run 2x4's inside the trusses to nail the seams to and the the ends and middle will be nailed to the truss's

 

[Firebird 1]

Funny how easy it is to spend someone else's money. For a pole barn, garage, an osb ceiling is fine. I would use 7/16 though instead of 3/8. With 3/8 I would put strapping on the bottom of the trusses 16" oc, 24" oc is ok for 7/16. Put the strapping on the bottom of the truss then staple plastic to that. That way the plastic will be against the ceiling board. I had one customer have me put 1/2" foil faced foam board for his pole barn that he used as a lawn mower workshop. It added a bit of insulation, was simple to install and reflected heat and light back into the work area. If budget is not an issue then metal would be nice or if the space is conditioned properly 5/8 gwb is good as well.

 

[Falcon67]

im gonna take my chances Im gonna run 2x4's inside the trusses to nail the seams to and the the ends and middle will be nailed to the truss's

Probably not much of an issue - I figure about 2.15 lb sq/ft of load on the lower chord using 2x4s and 7/16" OSB.

2 ea 2x4x8' - 22 lbs
1 ea 4x8x7/16 - 47 lbs

http://osbguide.tecotested.com/pdfs/en/tm420.pdf

 

[DougWil]

Funny how easy it is to spend someone else's money. For a pole barn, garage, an osb ceiling is fine. I would use 7/16 though instead of 3/8. With 3/8 I would put strapping on the bottom of the trusses 16" oc, 24" oc is ok for 7/16. Put the strapping on the bottom of the truss then staple plastic to that. That way the plastic will be against the ceiling board. I had one customer have me put 1/2" foil faced foam board for his pole barn that he used as a lawn mower workshop. It added a bit of insulation, was simple to install and reflected heat and light back into the work area. If budget is not an issue then metal would be nice or if the space is conditioned properly 5/8 gwb is good as well.

Whereas I think it is funny that people spend 90% of the money or time required to do it right or far better and don't..... like putting wood posts in the ground vs concrete.
Or my neighbor that installed ribbed steel siding on his garage and made zero effort to line up any of the screws. Looks like he sprayed them out of a machine gun.

I also find it funny that many here say insulating and finishing a pole barn is no harder or expensive that a conventional stick frame.
But here we are trying to hang a ceiling on 4 ft truss spacing.

 

[NUTTSGT]

Osb I thought would be the easiest to work with vs metal. I was going to staple plastic to the bottom of the trusses then run the nailers/2x4's then osb..

I hung OSB in my garage and metal in the house garage. I thought the metal was easier and faster to do. Once it's up, you're done. No priming, painting or caulking.

I have no idea why I thought putting the nailers up was a good idea... I can just fasten the osb to the truss... ends and center

i plan to paint the OSB

i just ran to stoneburners and priced metal sheets It gonna run me roughly $875 for the metal with no hardware 1.97 a linear foot. Cut to whatever length SO I just did an est for 3x12.

OSB ceiling is gonna be $418 plus a couple gallons of paint and hardware..

My shop is 30x40

OSB tends to soak up alot when it's finished. I've used 2 coats of Kilz primer which took more than 5 gals/$75, tubes of caulk and top coated with Kilz latex Pro-X paint. It might be a little bit cheaper but it's more labor intensive.

for a 3/8 sheet??

If you still want to do OSB, use atleast 7/16", it's more readily available and probably cheaper than the 3/8" sheets.


In the end, the next time I do a ceiling, it'll be metal with OSB on the walls.

 

[ExxWhy]

I have no idea why I thought putting the nailers up was a good idea... I can just fasten the osb to the truss... ends and center

i plan to paint the OSB

i just ran to stoneburners and priced metal sheets It gonna run me roughly $875 for the metal with no hardware 1.97 a linear foot. Cut to whatever length SO I just did an est for 3x12.

OSB ceiling is gonna be $418 plus a couple gallons of paint and hardware..

My shop is 30x40

I just did the inside of my shop, 40X44. I used metal on the ceilings and OSB on the walls. The metal is a LOT easier to work with (and looks nicer), plus when you are done hanging it, you are done with the job. Material was under $1100 with J-channel and screws. I screwed mine every 4' and it doesn't sag, so you should be good to go even with your 4' truss spacing. (mine are 24" OC)

The walls took 45 sheets of OSB. I have 13 gallons of paint on it, and it wouldn't hurt to put another coat on, though I am going to do without. Don't underestimate the labor to paint it, plus the cost of a lot of paint!

I am positive that all things considered, you would be happier with metal in the end even if the cost is a bit more.

 

[jeepnatv4life]

Thank you everyone!!! Im gonna frame out a grid every 2 feet with 2x4's to prevent sag. It will be the grid then 6 mil vapor barrier plastic and then 7/16 osb nailed to that. I will try and post some pics once its up Hopefully get thru it this weekend....

 

[Rod N]

I really think metal is the way to go. In the end they might be the same price and the install is so much easier.
1,200 sq. ft. you'll need at least 3 coats of primer/paint. I'm guessing 10 gallons @ $30.00/gallon.
Mine is OSB and I caulked the joints and then 3 coats and this was after the original owner painted it. Just the painting and I was up and down my scaffolding hundreds of times.

 

[jask]

The correct way to hang OSB on the ceiling is to use 5/8 gypsum board.

For the win!!

I am assuming that if you are insulating you will be heating as well? you really need to think about that fire rating of your materials.

 

[jeepnatv4life]

For the win!!

I am assuming that if you are insulating you will be heating as well? you really need to think about that fire rating of your materials.

Im not using a woodstove

 

[DekeT]

The correct way to hang OSB on the ceiling is to use 5/8 gypsum board.

This is the correct answer.

 

[larry4406]

In detached structures/garages, 5/8" gypsum board is not required. At least not in the detached garages my company builds in VA and MD provided no living space above.

 

[jeepnatv4life]

This is the correct answer.

drywalls not happenin

 

[OccupantRJ]

My trusses are 24" apart, so I installed osb with screws and used free 1x4 to back up the unsupported joints from behind. I would install a sheet, attach the 1x4, then install the next sheet. This gave me a 2x2 grid of joint support.

 

[strutaeng]

OP: consider 2x4 or 1x4 furring strips at 24" o.c. (furring running perpendicular to 4' trusses. For added strength, consider "blocking" all perimeter OSB joints. For even more strength, stagger your joints. Use 6" ring-shank nails on the perimeter and 12" in the field. There's information on the internet on these diagrams.

The weight of a wood panel is slightly less than the weight of a gypsum board per unit thickness, so I don't think weight is a problem.

There's a lot of hate by some folks for hanging wood panels in a garage/pole barn.

I did a bedroom with 15/32 plywood walls and ceilings before hanging gyp. board and I'm really happy the way it turned out. Properly detailed, wood panels have higher shear strength than gyp. board. Another advantage is that one can walk on the top of the plywood or OSB.

PM me if you have any questions.

Good Luck!

 

[zendriver]

Are your framing members at 4' centers like the OP has?

No, I missed that part, mine are 24".