Questions on the correct way to close a ceiling.

[Maineiacmoose]

Hey all

I am working on closing up my ceiling in the garage and I have a couple of questions.

First can I use a giant single piece of 9 mil Plastic as a vapor barrier? Its fairly inexpensive $70 and will cover the whole of the garage in one sheet. 30x50

Second I am using OSB for the ceiling and I am wondering if there is a certain way to run the pieces? Do I put them up across the trusses or do I go with the trusses?

Thanks for any help!

Maineiac

 

[matt_i]

I think using the air barrier will work, BUT, its going to be a pain to hang, stretch tight and keep straight the entire large single plastic sheet. A group of helpers would be good (plus extra ladders, scaffolds, etc). You might find it necessary to cut it and seam it back with tape just for reasons of handling it. Not sure how you're planning to attach it. Staples are appropriate but always underwhelming unless you have a pneumatic tool. I've never had good luck with hand held staple guns. A hammer tacker might be more appropriate but then there's the issue of a staple pulling thru. Squares of cardboard or milk jug cutouts can help to be washers but holding those in place while swinging a staple hammer could get interesting!

As far as hanging the sheets, for strength bridging as many chords as you can is best in my opinion, so perpendicular to the long way is best. Prepare to cut a few tapers or belt sand a few edges as buildings are rarely perfectly square. (When drywalling) I like to do the taper work on the leading edge (starting at a wall) and leave the factory edge on the trailing end. Seems like it makes the next sheet easier to put up.

Also don't forget you might need some "nailers" at the endwalls. Your endwall truss will likely be on the outside face of the wall and so there's nothing on the inside-face-top of the wall to land the panel edge on.

 

[Maineiacmoose]

Yes the size could be cumbersome but the shop is two large rooms. So two large pieces would be going up. I never thought about the end trusses I will have to put up some nailers for sure.

I have been using a air staple gun so far for the insulation and it has been a god send so far so good.

 

[NUTTSGT]

How far apart are the trusses ? If they are more than 24" OC, you're going to have to bridge that gap for the OSB.

Have you even considered ribbed metal ?

 

[Maineiacmoose]

How far apart are the trusses ? If they are more than 24" OC, you're going to have to bridge that gap for the OSB.

Have you even considered ribbed metal ?

I have actually. But I ended up buying a whole flat of OSB way back. The trusses are 24" and they are load bearing so the weight should not be a factor. Kind of on a tight budget these days so I need to use what I have all ready purchased for this.

 

[chinboys]

I would cut up small squares or rectangular pieces of cardboard to staple through as you are hanging and fastening the vapor barrier.
These cardboard pieces act like washers to spread the staple concentrated load out to prevent tearing of the vapor barrier.

 

[stm317]

Button cap nails might work too instead of taking the time to cut up a bunch of cardboard and trying to hold plastic, cardboard, and whatever you're fastening it with at the same time.

 

[machsnell]

I wish I had known to put up strapping for my drywall. I think that's the right terminology.

Basically running 1x 3 or 3/4x3 strips perpendicular to 24 oc trusses on 16" centers.

Gives more support and gobs easier to screw into your mark.

You could use the strapping to hold the plastic down even if temporarily without pulling through the staples.

Even if you had a few pieces of scrap screwed up every so often it would hold the plastic in place and you could staple between your scrap helper pieces

Sent from my SM-G960U using Tapatalk

 

[Maineiacmoose]

I would cut up small squares or rectangular pieces of cardboard to staple through as you are hanging and fastening the vapor barrier.
These cardboard pieces act like washers to spread the staple concentrated load out to prevent tearing of the vapor barrier.

Button cap nails might work too instead of taking the time to cut up a bunch of cardboard and trying to hold plastic, cardboard, and whatever you're fastening it with at the same time.

I wish I had known to put up strapping for my drywall. I think that's the right terminology.
Basically running 1x 3 or 3/4x3 strips perpendicular to 24 oc trusses on 16" centers.
Gives more support and gobs easier to screw into your mark.
You could use the strapping to hold the plastic down even if temporarily without pulling through the staples.
Even if you had a few pieces of scrap screwed up every so often it would hold the plastic in place and you could staple between your scrap helper pieces
Sent from my SM-G960U using Tapatalk

Would there be any benefit to the 1X3 strapping if I am putting up OSB? I plan on using some slats to temporally hold the plastic up while I staple it.

I have ordered some 6MIL 100' By 10' for $27 so I don't have to worry about the huge piece.

I have been thinking about putting sheets of hard insulation between the OSB and plastic since I only used R-19 on the celling. but i am not sure it would be worth the headache.