Metal Garage Insulation

[DWS91]

I'm new to the GJ but have been reading all of the threads I can about insulating an inexpensive, pre-fabbed, light gauge metal, detached garage/shop. I live in South Carolina (very humid summers). Many of you have hit all around what I'm proposing to do, but I can't find the answer I'm needing in regard to a hybrid option I am contemplating. My building is 24'x35'x9' with a vertical roof (1" hat channels screwed to 2 1/2" tube framing). I am on a small budget and want to use the Great Stuff to seal the very small crack at the ridge, the corrugations at the eaves and the corrugations at the horizontal wall panels, essentially "sealing off" all airflow. I plan to use 3/4" plastic HVAC strapping at 2' centers to hold R-13 faced fiberglass insulation in place, with the vapor retarder facing the inside of the garage. With no airflow, I want to know if I push the insulation all the way up to the metal roofing, not touching the roofing at the hat channels, will I get condensation there and will it be enough to cause problems down the road? The other option is to not use the Great Stuff foam at the ridge and eaves, and use spacers for my strapping to hold the insulation away from the metal roof, allowing the flow of air and vapor, though I don't see how much air will flow through the small opening in the ridge (1/4" maybe). This will introduce the problem of unwanted pests (wasps to name one) coming into my garage/shop. I plan to heat and cool the building for comfort all year long and I haven't found the answer about which way I should go on this.

 

[89Blazer]

I'm looking to build a very similar building this year, except I'm hoping I can get away with as big as a 28x36 and at least 10 foot walls. I'm in Aiken SC. Who did you go with for the building supplier? Your question is also something I've struggled with planning for. I'd like the building to insulated and climate controlled to an extent, although it won't be 24/7.

 

[DWS91]

I used a company called Elba Storage Bldgs, out of Elba, AL. The building came from TOL Bldgs (Top of the Line) out of NC. My guy at Elba was great and his name is Jon Isaacs. He was a great help for me.

 

[Zeke]

The only comment I have is about the plastic 'hangers'. Seems like they would work, but have you seen this done before at your proposed spans?

RE: the insulation spacing, I would call the insulation manufacturer's help line. But you should get some good answers here. Probably over 100.