Insulation for detached/unheated garage

[EchoFiveCharlie]

Hey everybody. Brace yourself, I talk a lot.

I'd like to preface this by promising that I have done a lot of reading and searching, but I guess insulation is just something I can't wrap my head around properly. Marginal pun marginally intended.

I have an older (1952) house, with a detached garage, in Georgia. The garage looks newer. If I was to wager a guess, I'd say within the last two decades. The house was built by the owner, and....let's be nice and say he was enthusiastic, if not particularly skilled. I believe the garage followed suit. The entrance door is crooked, the siding has a few gaps in it where light can shine through, etc.

Jumping to the point:

Like most folks, my budget is limited, but I'm looking to add a little insulation to the garage. Just enough to take some of the edge off the colder/hotter weather.

My mind is swimming with trying to learn about moisture barriers, vapor barriers, and the like.

I have a giant roll of 6mil plastic, that I considered covering the bare walls and maybe creating a ceiling with, to at least create an air pocket, but given that it would be a moisture barrier, I think I've read enough to decide that would not be a good idea.

I'm thinking insulation rolls in my joists would be the most cost effective, but also that I can't/shouldn't leave the paper facing outwards, due to fire code?

Or, would it really just be in my best interest to get a good sized window unit that provides heat/ac? At least until I can apply a better budget to properly doing the garage?

And yes, it does have gable vents. No other venting that I could see.

Thoughts, suggestions, criticisms, critiques?



Thank you in advance.

 

[Leaflessshadetree]

Which side the vapor barrier goes on depends on your climate.
Here (central Illinois) we put it towards the inside wall, just behind the drywall (or interior of choice).
Paper backed insulation is common on walls, but plastic can be used.

BTW: Uncovered vapor barrier and insulation in a garage (or any area that is used) is kind of temporary. I've never seen it last more than a couple months without noticeable damage.


Moisture barrier (house wrap) is different than vapor barrier, it allows some air/vapor to pass.

 

[K'ledgeBldr]

Being here in GA also I can give you some first-hand experience.

With a detached garage- and no plans to heat or cool; drywall the ceiling and have about an R-19 blown in. This is the biggest beater of the summer heat. Just adding the insulation batts will do nothing- you have to stop the convection of air and the radiant heat.

Since the winters are so mild, a simple space heater or turbo heater will take the chill off on those rare really cold days.

 

[Bretny]

Before i insulated i just stapled plastic up on the ceiling. It worked great in NY...as great as no insulation will. If your going to do this vent the attic real well as the heat wil build up in the summer.