I recently installed R13 (4-inch) mineral wool insulation in my unfinished garage, where I've got 2x6 studs. This setup leaves about a 2-inch air gap between the insulation and the future drywall or plywood I plan to put up once I finish the garage. I've heard mixed opinions on whether this is a problem—some say it's fine while others insist that I should just remove the batts and get 6-inch batts instead. However, when I asked for details on the risks of having that gap, I was told simply that 'it just doesn't work,' which wasn't very helpful. I'm not too worried about local codes but I'm trying to figure out if this gap could cause major moisture issues or if there's something else I might be missing.
1 Answer
Having that air gap can create stagnant air, which is a concern. Moisture can build up in that cavity due to temperature changes, potentially leading to condensation on the inside of the drywall. This could weaken the drywall over time or even lead to mold. It might not be an issue if your garage isn’t conditioned, but if you ever heat it, you could be setting yourself up for problems. I’d recommend filling those gaps with more insulation to avoid these risks, especially since you haven’t installed the drywall yet. Better safe than sorry!
Thanks for the insight! I’m planning on heating it during the winter, so it’s good to know that I should be cautious.