Question On Insulation

[FlyBy]

Sorry for in advance for no pictures, I'll have to shoot some later.

Buddies garage in question, 3 car (double door, single door) from previous owner. Was never insulated, so we decided for building cars in the winter (Volkswagens), we had to insulate it. A couple questions for all of you:

First Question:

A couple weeks ago, we insulated all the walls with R-13 (10 foot tall, 15" spread framing) that has a paper backing. Now the question is, we're not sure if we are going to sheetrock the walls or put plywood over them, but should we install a plastic vapor barrier over the insulation?

Second Question:

The ceiling is open trusses, and I know we can't insulate the actual roof because with the ridge vent, the heat would be lost. So should we just plywood the ceiling and throw R-13 (or higher) insulation on top of the plywood in between the rafters/trusses (we will be building an attic door).

Third question:

Should we pull the garage door track feet and openers from the ceiling and plywood in between them and the trusses, or should we just cut around them?

 

[Red Green]

First Question: The paper should have a plastic back that is your vapor barrier

Second Question: Yes or you could use pole barn steel for the celing to save some weight

Third question: I don't know

 

[rcozzo]

Second Question: Yes or you could use pole barn steel for the celing to save some weight

Menard's sells an interior steel lining. I had it put in my pole building for a ceiling. Mine is spanning trusses 4ft on center. Has R38 blown in on top of it. I stapled a vapor barrier to the trusses before installing the ceiling. It turned out really nice. I wouldn't change a thing.

 

[hidollartoys]

You can use plastic over the paper backed batts, it will help with air infiltration.

I would comsider what rcozzo did to hie ceiling. be sure that you use the vapor barrier like he described.

I would remove the track and opener to install the ceiling.

 

[timgr]

...I would remove the track and opener to install the ceiling.

I guess the issue is whether you can seal the holes you cut in the plywood well enough to prevent air infiltration. Removing the track solves that problem - no holes! You could fill the gaps around any holes with expanding foam, silicone sealer or aluminum tape: depends on which you think is easier, neater and/or faster.

 

[FlyBy]

First Question: The paper should have a plastic back that is your vapor barrier

Like a waxish looking coating? I'll have to pull some back and look at it.

Second Question: Yes or you could use pole barn steel for the celing to save some weight

That's a good idea, I'll have to look locally to check on prices.

 

[FlyBy]

I would remove the track and opener to install the ceiling.

I'm leaning more towards that too, and it wouldn't be that hard to re-hang the opener motor on the plywood, and the side supports can still be put back onto the studs that they're currently mounted too.

I'll make sure to get barrier plastic for the ceiling. What thickness would be sufficient you think? I'm most likely just going to go to Home Depot.

 

[hidollartoys]

I would suggest 4 or 6 mil. I have used 4 mil before and worked fine.

 

[jklingel]

I would not rely on the "paper" on your batts to be a vapor barrier. There are just too many little slits, etc, for me to be confident w/ it. VB is dirt cheap and fast to install. I would not even question its use. Too, run a bead of Tremco Acoustical Sealant around the perimeter of the wall/ceiling (over you insulation ears/tabs on the studs) before applying the visqueen (6 mil. I am too hurried/clumsy for that wimpy 4 mil stuff). That helps seal under the visqueen. Are you using Tyvek on the outside, or do you not have much wind?

 

[FlyBy]

We started the ceiling last night, 4 mil vapor barrier, 1/2" plywood. It's moving along nicely. Not sure what we're going to do with the walls yet, so we haven't put a vapor barrier on those yet.

The outside of the garage was finished before my buddy bought the house, but we found out that it has Tyvek behind the siding. Once we get the first row all set we're going to lay in 24" wide R13 between the trusses