Attached Garage Insulation ? (WI)

[Badger05]

Looking to insulate the walls in my garage (and ceiling eventually) before I hang osb on the walls. My garage is attached to my house and the common wall is insulated/drywalled. The outside garage walls are currently open 2x4 16" OC. It gets pretty cold here in WI with plenty of nights in single and negative temps.

I have no plans to install heat in the garage, just want to get the proper insulation in there before I close off the walls with sheeting.

Would I be okay using rolls of R13 with the kraft faced side on the inside and stapled to the studs? Or should I just use insulation with no paper side and put up poly for my vapor barrier. Price is pretty insignificant between those two options I assume. Or is vapor barrier not going to be very important since I'm not actually heating the garage?

My garage ceiling has drywall hung but is not insulated. Would I be ok laying rolls of insulation down with the kraft side down, then laying another layer of insulation (with no kraft) perpendicular?

I've been doing alot of reading here to learn as much as I can, just wanted to run it by some of the great minds here before I do anything! thanks!

 

[DRMay]

Four mil poly is the best bet with standard batt fiberglass insulation. Caulk with accoustical sealant at all seams. If your studs and the lower cords of the roof trusses are bare make sure your poly forms a continuous barrier. Assuming your wall plate sits on a concrete floor, terminate the vapor barrier at the bottom wall plate but do not seal it to the floor. The bottom plate may be subject to moisture so it should be able to 'breathe'. Make sure you have access through a hatch to the ceiling. If you use blown-in insulation it will make things easier. Do your wiring first, of course.
A warm car engine should be enough to maintain some heat overnight. We've had -48 degrees C with the wind chill here, and I never have to plug in the vehicles. An insulated garage door is a definite plus.
Make sure the 'attic space' above your garage is ventilated to the outside as well. This will prevent the collection of moisture in the form of frost on your rafters. It ends up puddling on your ceiling and may damage your drywall or OSB.
Hope this helps.
p.s. Try doubling the ceiling insulation to R20. Amazing difference!

 

[HomeBrewA4]

We do kraft paper towards the drywall. In our zones latest code, it says you can even do unfaced and use a latex paint on the walls and by code, would be considered the vapor barrier. We have yet to meet an inspector that will look at paint in a house, they'd rather have it done in kraft. If you want the most out of the 2x4 on a fiberglass budget, call around to some insulation companies and get priced r15.

Depending how your housing market is, most of the time you can get insulation installed and done by a company for less then you buying it at lowes/hd, let alone your time of installing it. I know we are considerably cheaper then the box stores and that is our price out the door.

Ceiling material. If you are hanging the ceiling like a normal ceiling but only in OSB and not drywall. I would batt it with a r38 kraft.. paper against what would be the OSB when hung.

 

[Badger05]

Thanks for the comments.

The ceiling already has drywall hung. Garage attic is shared with the house and is also vented properly through soffit vents and ridge vents at the top of roof line.

Good suggestion to see what a local company could do it for. Wouldn't take them an hour even I bet and they probably get the product for better costs than I could. Plus I wouldn't have to waste a saturday messing around with it.

 

[ShumanSS6.0]

I just blew in cellulose this past Saturday into the garage attic. I went through 65 bags @ 6.55ea plus the rental for $50. It took 3.5hrs to get through it all and my garage is 28x22. You need 3 guys but could get by with two. I added some poly foam to the back of the access door and closed her up. I'm doing it once and wanted to put more than enough up there. Thickness ended up being 16-20" throughout. You definitely want a vapor barrier on the walls, doesn't matter if you get the rolls with or without facing. I would suggest 6mil, little more expensive but worth it in my opinion.

 

[James-W]

I used the paper faced insulation on the new garage and stapled it to the studs. I have 2X6 walls and a 2X10 ceiling so I have R-19 in the walls and R-30 in the ceiling. I had originally planned of having the foam insulation sprayed in before putting up the drywall, but when I checked on the cost to have that done it was triple the cost of the pink rolls of insulation. So I decided against the spray foam insulation, although from everything I have read the foam type insulation is the better way to go. I just couldn't see spending three times the amount to insulate the garage.

 

[skelrad]

Badger05 - I'm interested in hearing what you end up doing. Your setup sounds identical to mine (and I'm also in WI). I'm in the process of running additional wiring to the garage, but will be ready to insulate pretty soon. Curious if you end up getting a quote that is cheaper than installing it yourself.

 

[Badger05]

Badger05 - I'm interested in hearing what you end up doing. Your setup sounds identical to mine (and I'm also in WI). I'm in the process of running additional wiring to the garage, but will be ready to insulate pretty soon. Curious if you end up getting a quote that is cheaper than installing it yourself.

Honestly it's pretty low on my priority list at the moment since we're not in the dead of winter anymore. I will probably get around to it this summer and use paper faced bats in the wall cavities so that I can get the walls sheeted and start hanging cabinets, workbench, etc. Although I will make some calls to see what it costs to get contracted out just in case it's comparable to doing it myself. Let me know what you end up doing as well.

 

[gabe2365]

I'm in Madison WI just finished my attached 3 car garage. I did unfaced r11 ,r13 would be better, with poly vapor barrier over it and taped all of the joints then osb on the walls. For the ceiling if you don't want to drop the drywall to install poly saving hours upon hours of work get a closed cell spray foam kit and spray about about 1/2 inch on the studs and drywall ceiling from the attic to provide the vapor barrier then blow in either fiberglass or cellulose on top of the foam. Menards lets you use the machine if you buy the insulation from them. Good luck.