I have a 20x22 detached 2x4 framed garage. I'm wanting to convert it to a finished 100% of the time heated and cooled space for my office/Man cave. I will be insulating the walls/ceiling and sheet rock or other finishing material. I'd like to leave the insulated garage door rather than removing it and walling it in so I can still bring larger things into the space. My main concern is what to do with the slab. I could put down insulation panels and cover it with OSB but the raised floor lip will cause issues when trying to bring things in through the garage door. What other options do I have? Can I get away with just leaving it and since I’ll be hearing it all winter it will warm up and stay warm? TIA
Heating MN garage
- Thread starter bigcsw
- Start date
pcmeiners
Well-known member
No slab insulation at all ?
This garage was there when I purchased the property so I don’t know if there is insulation under the slab or not
WisJim
Well-known member
You could dig out around the foundation and put some foam board insulation down a couple of feet. You can get styrofoam with a gravel or cement finish that holds up pretty well.
You don't need to insulate the slab.
My old garage (central MN) is slightly bigger than yours. It was completely unfinished 2x4 construction when I bought the place. Conventional poured slab, not insulated. First insulated ceiling with staple up batts. Later finished ceiling and insulated walls with best insulation for 2x4 construction. Worked well. Still heated and cooled year round. My renter loves it. (Cooling is just a 220v thru wall A/C unit, very effective)
My old garage (central MN) is slightly bigger than yours. It was completely unfinished 2x4 construction when I bought the place. Conventional poured slab, not insulated. First insulated ceiling with staple up batts. Later finished ceiling and insulated walls with best insulation for 2x4 construction. Worked well. Still heated and cooled year round. My renter loves it. (Cooling is just a 220v thru wall A/C unit, very effective)
I have a 24 x 24 attached garage in the Twin Cities. It's old 2x4 construction. I put fiberglass in the walls, and blow-in insulation in the ceiling. I finished the walls with 7/16 OSB. (not sheetrock) I also had a 2" thick full insulated garage door installed. That thing has been great. I keep the garage heated full time in the winter, around 60-65 degrees. We have a bathroom (toilet and urinal, no bath or shower) so I like to keep it nice in there. I don't lay on the garage floor very often but I have no problem with it ever being cold in there. I can turn the thermostat to any temperature I want and it will get there, and stay there with no problem, even when its 25-30 degrees below zero outside. If you plan to do a bunch of auto repair work while laying on the floor, it might be an issue.... but otherwise I wouldn't worry about insulating the floor. It will eventually warm up to room temp and you'll never notice a difference. Oh, by the way, I heat with a 45000btu Reznor natural gas unit heater hanging from my ceiling.
Thank you this is what I thought. I won’t be laying on the floors and there won’t be cars in the space so I should be good!
ambenz
Well-known member
I second adding hard foam insulation around the outside perimeter of the garage. The slab will retain more heat and become a heat sink....or add padding and carpet on top of the slab. They put tapestries and rugs in castles walls and floors to retain heat. I have remnant rugs I got from the dumpster on my floor to keep heat and avoid flat spots on my stored car tires. I also have a small fan connected to a Winter Watchman at the farthest point of the furnace and when the temp falls below 55F, it turns on and blows cold air towards the thermostat to cycle the furnace. You can see the different carpets on my floor...good on the knees too! The get too dirty and I toss them and go junking for more....
