Detached garage insulation question....

[simpsoap]

We have a 24x48 detached garage that I'm turning into my workspace, and I have a question about insulation. the attic has no insulation, and I've read mixed inputs on using a vapor barrier or not. I'd like to do the work myself, and want to do it right. I'm trying to find out if I should buy faced insulation, or if unfaced will be fine. The garage is already drywalled and there is currently no vapor barrier on the back of the drywall. I'm not planning on putting a floor in the attic space or using it for storage.

TIA!

Andy

 

[ODIS]

We have a 24x48 detached garage that I'm turning into my workspace, and I have a question about insulation. the attic has no insulation, and I've read mixed inputs on using a vapor barrier or not. I'd like to do the work myself, and want to do it right. I'm trying to find out if I should buy faced insulation, or if unfaced will be fine. The garage is already drywalled and there is currently no vapor barrier on the back of the drywall. I'm not planning on putting a floor in the attic space or using it for storage.

TIA!

Andy

In my attached and detached garage spaces, there is no vapor barrier in the attic. Both have insulation that was blown in.

Hope this helps.

Ody.

 

[Steevo]

Even the living space in my house, built in 2009, has no vapor barrier above the ceiling sheet rock. Just blown-in insulation.
This is how I did my shop as well.

This may be because properly vented attic spaces breathe, whereas closed in walls do not.

 

[Gary S]

When in doubt, use insulation with a vapor barrier. If you don't heat the garage full time, you likely won't notice the difference, but if you omit the vapor barrier and just once have a water problem, you will wish you put it in.

 

[rsa]

Depends on the climate zone you're in.

Here's an earlier post, with references, that could answer your questions.

 

[fourjeepin]

I used faced in the walls of my detached garage, formerly a carport. I was going to do the same thing in the attic, but the insulation guys all recommended blown in. Their reasoning was you don't get gaps between the pieces. This made sense and seems like it would be cheaper and quicker. I plan to do it in the fall. Wish I had done it in the spring as it gets ****** hot in there this time of year.

 

[kbs2244]

Ideally you would not need a vapor barrier.

BUT, and that is a big but, that would require a well vented attic.
Roof and soffit vents.
That lets the vapor escape.
I doubt you have either kind of vents.

But if you use a vented heater and do not wash the cars in the garage you should not being making as much vapor as you do in a house cooking and showering.

In your case, I would put in at least two roof vents, paint the walls and ceiling with a vapor proof oil based paint and wash the car outside.
And use a vented heater.

That will minimize vapor production and give some way out for what you do make.