If I'm trying to insulate a detached garage in the Midwest, would it be better to use a rating higher than R13?
I don't really know too much about this kind of stuff. Would it be better to use a rating higher than R13 (recommended) since it's detached rather than part of the house? Or am I overthinking the detached garage being surrounded by the outdoor temps during the winter as opposed to the walls bordering a heated house? My goal is to use the garage as my at home gym. I don't expect it to stay warm 24/7, just insulated enough to maintain heat while working out and running a space heater.
2021-04-03T00:08:20Z
I don't know if you want to call it an attic. I guess it has the potential to possess one, but no ceiling was ever put in, just framework beneath the roof.
2021-04-03T00:09:31Z
Insulating that was also part of the plan, just not at the moment. Focusing on the walls first. I don't even have a ladder to reach that high.
NickD2021-04-04T04:02:36Z
R-13 will fit perfectly in a standard 2x4 framed wall. That's exactly what it is made for and that's what most builders in the Midwest use on exterior walls.
But most of your heat will escape up through the roof. If you get the foil backed Styrofoam sheets that come in 4x8 pieces you can easily nail them across the bottom of your rafters with the foil facing down into the garage area to reflect the radiant heat back into your garage. Most of that is not a really high r factor but it will make a big difference over having nothing. One caution, styrofoam has a very very low ignition point and if you have a fire the smoke from the Styrofoam is very toxic.If you have room, can you build an exercise room in your detached garage that can be enclosed with a door? that way you only have to heat inside of that room, and you can build something that can be easily insulated, both the ceiling and the walls.
As others have said the more the better for both heating and cooling. I had my inside roof insulated because I converted the upper part of my garage to an office. They used ventilation baffles in between the rafters and insulated with I think r19 then drywalled it, it’s my office man cave.
The Rating for the garage doesn't need to exceed the R rating for exterior walls of the main building. In point of fact, exterior walls are exterior walls. For MOST garages, at least 2 walls are exterior even if it is attached.
More insulation is always better than less. And the roof or ceiling loses more heat than the walls do, because heat rises. That would be the best part to start with. Buy a ladder. If you have no plans to create an 'attic' space, then install a ceiling and insulate on top of that. If you don't have a ceiling, then a good deal of any heat in the place will be up near the roof, not down near the floor where you are.