I am about to drywall and insulate my detached garage ceiling. Instead of stapling the kraft faced pink fiberglass insulation to the ceiling joists, I was thinking I could save a step by sheetrocking the ceiling first and then dropping in the insulation (paper side down) and save myself the stapling. Will I have a vapor barrier issue, or is this a bad Idea?
this is way more work..... not to mention trying to manuver in the attic space and not putting a foot or leg through the celing.. Another alternative to think of is blown in insulation the COCOON brand (recycled paper treated) is way less exspensive than bats and you can do it yourself with a rental unit.
snipped-for-privacy@yahoo.com wrote:
I just did the very same job in my garage a few months ago with R-38 batts. You want to insulate first and then put up the sheetrock. MUCH easier and more precise than trying to maneuver in the in the attic and do it afterward.
This is a bit off topic to your question, but since you mentioned vapor barriers, I figured it an appropriate thread to inject a comment.
Is the garage going to be a "conditioned space" and have moisture sources? Will you be using the attic for storage or will it be totally isolated from the downstairs? Do you live in a hot moist environment or a cooler one?
A vapor barrier in a garage doesn't make any sense to me. Typically, a vapor barrier is to prevent moist air from getting into a cold space, condensing on the cold surfaces, and leading to moisture issues.
In a garage, there's not much of an air envelope so the inside air would appear to be no different than outside. Perhaps with the doors all closed, the garage will experience less temperature and humidity swings than the outside, but overall, it's very different from a house that is filled with moisture sources that will drive humidity through the walls/ceiling.
That said, I've not seen many garages that have air sealing between the attic space and the main garage. Hence a vapor barrier on your ceiling will do nothing since the humidity throughout the garage would be relatively uniform.
If I were in your shoes (and I sort of am because I'm just about to build a detached garage), and I wanted to use the attic space for storage (which I do), I would put a perforated radiant barrier directly under the roof deck then insulate the upper cavities so that the outer shell of the garage is insulated. It sounds like you're further ahead on the project however. In that situation, I'd still use a radiant barrier under the roof, then blow cellulose into the attic space and avoid the pink stuff altogether.
Don't be talked out of a vapor barrier. I finished my attached somewhat oversized two car garage with sheetrock after I insulated the ceiling and walls several years ago then I put in a gas heater, vented of course, to keep things from freezing with it staying around 40 in the winter. Just last month, I put in a washer dryer combo so I don't have to walk down to the basement so often. So as to not have to vent it where I didn't want to, I got an electric dryer and it vents into the garage. It gets rather humid now and I'm glad I did it right years ago.
You might get slow yourself go>> I am about to drywall and insulate my detached garage
We frequently insulate after hanging the board however we use continuous poly vapor barrier and unfaced insulation almost 100% of the time. The remainder is blown with continuous poly vapor. The end result is a job
10 times that of a paper faced job.If you do go with insulating after you hang the ceiling just install a continuous poly vapor barrier, hang the ceiling, then either drop in unfaced attic batts from above or use blown. Dropping the faced batts in from the top will leave large leaks in the vapor barrier. This could become an issue in the event the space is ever heated which is I am sure why you are insulating in the first place.
Mark
He would not need a vapor retarder if the space is not heated. There's a huge amount of infiltration around the overhead door, and any moisture buildup would dissipate in that manor (path of least resistance.)
If it were me, I would insulate with unfaced batts (support with plastic strapping until the drywall is installed.
I agree. Considering the almost negligible cost of poly and labor, why would anyone NOT bother to install a poly vapor barrier before installing the drywall? The fact the it will help to hold the (probably cheaper, I have not seen faced fiberglass for many years) unfaced fiberglass bats in place is just a bonus.
Most of us seem to have pink and poly in the garage for years before we get around to putting up the drywall. It often seems to take several more years to get the taping and mudding done.
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