Best way to insulate an existing attached garage?

[Pony_Driver]

Op you doin this or writing a check, seems like you are doing it.

If I do it I’ll do it myself. I am pretty sure it’s all vapor wrapped, but I would have to make sure I have the styrofoam soffit vent things in place so I don’t screw up the airflow.

 

[Talon2006]

Sprayfoam the inside of the T11/studs, put in 3/4" to 1" of closed cell, then put your batts inside of that.

Aaron Z

wouldnt that 3/4-1” compress the Batts just enough to hinder the insulating abilities?

 

[Benny]

wouldnt that 3/4-1” compress the Batts just enough to hinder the insulating abilities?

Compressing it that much won't hurt it. You won't get full R value, but you will get the same R value per inch of actual wall thickness. Of course, that 1" of closed foam will add a lot.

 

[FleshEater]

The real question is... do you have a vapor/water barrier around the outside?

My garage is T1-11 directly on the studs on two walls, and tar paper on the other two walls. Everything I have read suggest if I throw insulation in there i am going to get into wood rot issues...

Is your T1-11 painted?

 

[FleshEater]

I feel like vapor barriers aren’t as essential on finished out buildings, unless they’re constantly being climate controlled inside.

My garage is only heated when I’m out there. So unless I wrap the inside and outside, the vapor barrier is useless as the building is not air tight like my house and it has a concrete floor that just radiates cold damp air. Plus the doors are open most of the summer.

Also, painting with acrylic is pretty much the same as a thin layered mil plastic. Each coat of paint is a mil or more of protection, depending on how thickly it’s rolled out.

 

[Talon2006]

Is your T1-11 painted?

Yes.... But I still see trouble running ac inside here in Houston.

 

[Seubs070]

I would just blow insulation in the attic and leave the walls alone. It's really only one wall that won't be insulated. You have the two walls that adjoin the house and then the third wall is garage doors. The attic will give you the most bang for the buck.

I insulated my detached garage a few years ago. The walls were mostly insulated with fiberglass batts, and I blew R60 into the attic. R60 was only like $300 and lowes gave you the blower for free. Took me and my dad a few hours and it was done. The difference was noticeable as soon as the attic was finished. Much cooler in the summer and warmer in the winter.

 

[Pony_Driver]

I would just blow insulation in the attic and leave the walls alone. It's really only one wall that won't be insulated. You have the two walls that adjoin the house and then the third wall is garage doors. The attic will give you the most bang for the buck.

I insulated my detached garage a few years ago. The walls were mostly insulated with fiberglass batts, and I blew R60 into the attic. R60 was only like $300 and lowes gave you the blower for free. Took me and my dad a few hours and it was done. The difference was noticeable as soon as the attic was finished. Much cooler in the summer and warmer in the winter.

Good to know, thanks. Did you insulate the garage doors?

 

[Seubs070]

Good to know, thanks. Did you insulate the garage doors?

I think it is insulated. It's double-sided with metal a metal back so I assume it is insulated. If I had the normal uninsulated one I would buy a kit to insulated or just cut up some rigid foam to fit.

 

[Stuck]

I would just blow insulation in the attic and leave the walls alone. It's really only one wall that won't be insulated. You have the two walls that adjoin the house and then the third wall is garage doors. The attic will give you the most bang for the buck.

I insulated my detached garage a few years ago. The walls were mostly insulated with fiberglass batts, and I blew R60 into the attic. R60 was only like $300 and lowes gave you the blower for free. Took me and my dad a few hours and it was done. The difference was noticeable as soon as the attic was finished. Much cooler in the summer and warmer in the winter.

If youre going to blow the attic you might as well drill and blow the walls. Its the same insulation and machine. You just stick a nozzle on the end of it. If they dont have a nozzle you can make one out of a funnel.