No Insulation in finished garage

Our walls are up already in the attached garage….. I always assumed they were insulated. No such luck.

Just had a garage heater installed and found that the wall voids are empty. I’ve got osb on 3 walls. T-111 siding on the outside.

My ?’s –

what’s the quick, yet best way to insulate?

Must I remove all the osb walls, fill with rolled R? & replace ?

Must I put a vapor barrier up before replacing the osb?

Remove OSB, insulate w/ R13 (or R19 if they are 2×6 walls), poly vapor barrier, reinstall OSB or drywall.

If you do not have insulation in the garage attic you are wasting your time insulating the walls however. Your heat is going out the lid long before the walls help anything.

I would say remove osb and put r-15 or r- 21 in depending on if it’s 2×4 or 2×6. Up to you on vapor barrier, what is the ceiling or your plan?

Ceiling is batted insulation (r value unknown) – plastic – osb

Once everything is done if you really want to help your heat bill, put chute vents in and blow in another 6-12″ in the attic, really helps filling all of the gaps.

That’s a great idea. Starting to wonder if I have time to get it ready for heat before winter smacks us.

If you’re like me and have high amounts of shelves, cabinets, and larger items hanging from these walls, or maybe the OSB is just too difficult to remove you can drill holes in each stud cavity and blow the insulation in. Not the greatest at times as it will not always get every location especially if there is blocking in some areas, but for a garage it would be more than adequate. And definitely the quickest option.

I work in the field of weatherization,so this is right up my alley.
since your osb is up already,i would look at densepacking the walls with blow in,as mentioned above.
snap a chalk line near the top of the cavity and drill 3″ holes in center of cavity,you can buy 3″ tapered plugs to drive into the holes,or chalk a line 6″ below cieling and remove osb plug cavity with a piece of foam and blow it full,replacing the strip when your done.
we have done vertical from the outside,snapping a line and covering holes with a trim board,usually blowing up and down from the center of the wall or where ever trim would look best.
This can be done with the blowing machines from the lumberyard,but will be slower than with the blowers I use.
Less on the product and more on the air will give you a denser pack,voids shouldnt really be a problem if you blow this way,of course I use a thermal camera to check progress while we blow to spot any voids.
I prefer to use cellulose over fiberglass,in this situation I think you will get a denser pack with the cellulose.As far as vepor barrier goes I think a good humidistat fan will take care of any moisture issues.
Hope this helps,Good Luck!!

It’s officially a mess but I’ve decided to strip everything down to the studs, insulate it properly & assure that it’s done right.

We got 3/4 of the walls we have to do opened up today already. Luckily I have fantastic neighbors.

I bought the R15 kraft faced stuff from menards tonight ($251). I’ll prolly add a few outlets while the walls are open.

Can’t wait to have a heated man cave/ garage this winter.

Thanks so much for all of your input and advise.

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Good choice on insulation.
Now throw the osb away and use something else.

MnPat1 wrote:

Good choice on insulation.
Now throw the osb away and use something else.

What is the something else? I will be in the same position in the near future. Thanks.

I had 7/16 osb in my last garage and it was awesome.

I had OSB in a previous house. Nice that you can hang most items anywhere without worrying about studs and it’s very inexpensive. Drawbacks outweighed that though. Was very dark and you couldn’t add enough lighting to offset it. Trying to paint it was horrible, it soaked up gallons of paint and no matter how many coats of primer and paint you put on it the glues just bleed through and you get brown streaks everywhere. If I used OSB again I’d likely put polebarn tin over it.
My current house has knockdown textured drywall on the walls and ceiling and so far of all my past houses it’s my favorite.

I’d use OSB in a heartbeat.
I wouldn’t use kraft faced insulation though. I’d use 6 mil poly and seal it at the plates for my VB.

I’d go with steel or sheetrock myself, they look so much better than osb.

Still chugging along on this nightmare of a project. Sweat like a mule today out there and thankfully made some headway. I’m gonna need more Busch Light tomorrow but I’ll be out there again every day this week, winter is coming.so far I’m sticking with the plan of osb. Going to get everything insulated & closed up, then painted right away. Then I can get the heater vented and supplied with propane from the main tank.