Insulating a Metal Garage

[ncgarage]

Hello everyone.

I am in the process of building a 40x52 metal garage from Alans Factory Outlet. I have been doing alot of research on the insulating of the building(diy options). In my opinion it seems that one of the optimal solutions might be to take one of the diy spray foam kits and do all the crevices and come back with either foam board or fiberglass insulation? I'm in central North Carolina and I only plan on heating and cooling sporadically so I do not need "super insulation". It doesn't seem like very many people have done this? Any thoughts?

 

[StefanNH]

I’m using fiber glass rolls in mine. When I finish it I may put a layer of rigid insulation behind the walls.

 

[gimpyrobb]

I have a 30x40 metal building. If you really want it insulated, its kinda a PITA. I put 2 inch thick foam against the sheet metal to fill in-between the metal structural tubes. Then I put up 2x4 framing to use fiberglass batt insulation. If I just put the foam up, the tubes would be uninsulated.

 

[charlie101]

I have an 18x45 from Alan's and did spray foam (not DIY) with 2.5" on the walls and 3" on the ceiling. I covered the walls with OSB and have been happy with it.

 

[ncgarage]

If I was going to use it more often I would definitely go all the way with spray foam. My house is spray foamed and we love it. However, since my usage will be sporadic, i'm trying to keep the cost down. Sealing all the seams and crevices where the building comes together with a diy kit would stop the air intrusion and since NC is a pretty mild climate most of the year I am thinking I could get away with using 1" foam boards. I know the metal tubes have quite a bit of thermal bridging but if that ends up being a problem I could cover them in the future. Thanks for your comments.

 

[DaChev]

People generally don't go with the DIY spray foam because it doesn't work well and is very expensive. Once you look at getting a professional crew out to seal the cracks you will likely find that having them spray 2" layer on all surfaces is close enough in price and then you don't really need to spend more on insulation.

Metal buildings get HOT HOT HOT in the sun. Mine would commonly be 10°F higher than the outside temperature in the summer until I got the spray foam in. Consider that amount of heat transfer getting into the space between the metal and the foam board, or fiberglass batt. That small space will see significant temperature and humidity changes that will either leak into your space, and/or cause damage to the metal skin.

Buy once, cry once.

 

[My Old Tools]

Whatever you do, double it on the roof. I used roll fiberglass on the frame of my red iron building, then had 8" fiberglass strapped on the roof. It makes a huge difference in heat gain.

 

[ncgarage]

I found this guy who used Kraken diy spray foam in cans. After watching dozens of canned-kit videos, this one applies the most evenly by far. Still leaning towards my original idea. In another video on his channel he ends up putting foam boards on his ceiling. Thanks again for the comments.

 

[Mike65]

We also did spray foam on our 24'x25' shop/garage. I usually spend a couple hours a day out there so having it well insulated was necessary since right now it is not heated or cooled.

 

[ncgarage]

That looks like a nice job, nice and even application. Did you paint it white for lighting purposes?

 

[dcg9381]

People generally don't go with the DIY spray foam because it doesn't work well and is very expensive. Once you look at getting a professional crew out to seal the cracks you will likely find that having them spray 2" layer on all surfaces is close enough in price and then you don't really need to spend more on insulation.

I don't do DIY spray foam because it costs me more to do it than it does to have it professionally done. There are good kits out there with quality form, but I wouldn't use them for anything other than limited areas and repairs....

In my opinion it seems that one of the optimal solutions might be to take one of the diy spray foam kits and do all the crevices and come back with either foam board or fiberglass insulation? I'm in central North Carolina and I only plan on heating and cooling sporadically so I do not need "super insulation". It doesn't seem like very many people have done this? Any thoughts?

We've done hybrid insulation before and I think it's a good plan.. Probably the only economical way to "DIY spray foam". I assume as most of your insulation is "traditional" that you'd vent the roof and soffits? I assume no attic.... For a 40x50, the roof deck is going to be a PITA.

 

[ncgarage]

I'm planning on it being wide open on the inside. Venting the roof and soffits is an area I'm still not sure about. Definitely don't want condensation. I would love to seal up the building nice and tight to prevent bugs and anything else from getting in. This is why I was thinking about diy sprayfoam for all the creases, including the roof peak and soffits. I'm somewhat worried about condensation between the foam boards and the roof and walls but it seems for most people this has not been a problem. I'm also still not sure which tape I'm going to use. Some people have had problems with certain tapes coming off after a few weeks.