Sanity Check on Metal Pole Barn Insulation Plan

[americanspirit]

Hello Garage Journal,

I have spent the last week reading through all nine pages of search results for "pole barn insulation" discussion.
I would like to solicit feedback from this group on my plan to insulate my 48'x35' metal pole barn based on that research. My buddy and I are going to tag team this install. The goal before freezing weather hits is to have the ceiling insulated so that I can slowly chip away at the walls.

I will be using the shop to work on vehicles and also prefer to keep it above freezing when I am not there.

Here is the building I am working with (I am in northern Pennsylvania):


48' long x 35' wide
10' from concrete floor to top of header
Joists are 4' on center
Existing ventilation is provided by soffit+ridge vents the length of the building on both sides, no gable vents exist today

The only existing insulation:

• (I believe) poly-iso boards attached behind the roof purlins
• an insulated 16' garage door

The existing 'holes' to the outside:

• 16' insulated garage door
• 3' service door
• 2x non-insulated glass windows

The plan:

Ceiling

1. Build/install walkway access along the length of ceiling
2. Build/install 30"x30" access hatch
3. Install 6 mil plastic sheeting across entire ceiling
4. Install 28g steel liner panel (white) across entire ceiling
5. Figure out how to guard the soffits from loose cellulose, 4' on center (foam board?)
6. Blow in many bags of cellulose insulation (14" thick? R-as much as is practical)

Walls

1. Spray foam all cracks between walls and footer
2. Install 1.5" foam board between girts to match thickness of girt boards
3. Metal tape or spray foam all foam board seams
4. Frame out walls 2' on center
5. Install non-faced rockwool insulation batts
6. Cover walls with plywood or drywall

Am I on point with this design or are there areas for improvement? I would prefer to overdo it than cut a corner on this project. Many people have suggested spray foam but I am leaning closer to rockwool because of costs and I can DIY the install without having to learn a specialized skill (spray foam application).

 

[1wook]

I think you have a good plan and it's similar to what I did. A few tips:

1. Don't waste time overbuilding your walkway, you won't use it often!
2. Make the access hatch the width of your liner panel, and build it when you reach that point of installing the panels.
3. I found that 8' wide plastic was easier to install than 12'
4. Use foam board or cardboard to block off the soffits and wall cavities.
5. Get scaffolding for all the ceiling work, so much more efficient than ladders. I had my kids push me around and pass me supplies so I didn't have to go up and down as often!
6. Make a plan for how you're going to keep your lights powered and your electrical for the garage door opener.
7. I used a drywall lift with a piece of foam board taped to it to install the steel sheets. I assume you're running your steel lengthwise and aren't using 48' long panels. Either stager the seams/overlap or use J trim to make a nice transitions. 16' long panels are easy to instal with a drywall lift.
8. Spray foam between the lowest girth board and the steel can cause the steel to push out and result in trimming spray foam.
9. I installed foam sheets in the wall cavity instead of between the girths for a faster install and spray foamed around the perimeter. But if I would have done it the way install the foam with a 1/2" gap on the top and bottom sides and spray foam the gap, don't waste time cutting it perfect and trying to press it into place.
10. I also framed out horizontally instead of vertically and it worked well.

 

[FMB4]

I failed the sanity check, so I can't answer your Qs (1wook above nails it tho). But, that is one a heck of great building you've got there, er... sanity check... pole barn. Good luck, and we're all looking forward to seeing what you park/place in it.

 

[jack stand]

Sounds like a good plan.
To separate the soffits, a lot of contractors will...
1. staple up the cheapo styrofoam baffles to the roof purlins into the soffit space
2. run a lengths of as thick as you can get f/g batts (r-30 = 12" r-49 = 15.5) filling in between the trusses and outward away from the soffit and the top corner of the batt up against the baffle. This is your "block" and insulation for the top of the wall and close to 4' of the ceiling.
Then blow in the rest of it.

 

[americanspirit]

Thank you for the replies. They have got me thinking through to the end of the plan. There is a lot of stuff I hadnt considered.

From the explanation above I now understand the 'block' using an insulation bat and foam baffle to prevent the blown insulation from falling down into the soffitt/wall cavity.


1. This is a good point and the less "extra" weight on the joists the better
2. NOTED. My panels are 36" wide. It's my first time doing this and wrong sizing the hatch would be an easy mistake to make
3. I am used to working with 8' sheets of material, it makes sense to try 8' wide plastic
4. PA can get wet, foam it is
5. I have 1 scaffolding setup on wheels in there now, I could borrow another if it made sense
6. Fortunately it's wired for 110 all around. All the wiring is above the ceiling (flexible metal conduit). I will have to figure out a way to keep cellulose off of the top of the lights
7 I can and will borrow a panel lift on this advice
8. I foamed 1 eight foot floor area at the back of the building to test what I was up against. I learned the hard way the foam seeps outside of the metal. I was considering alternatives to prevent it from oozing out... Like using gaffers tape temporarily on the outside until the foam cured. Or maybe finding another way to air seal the floor seam.
9. It might be cheaper (less material) and easier (less time) to install in front of the girts instead of in between them. I had planned on doing exactly what you say NOT to do -> cut them to exact size and try to force them in. Then foam around the seams. I like the idea of leaving clearance and then foaming the seams.
10. I had never considered horizontal framing as an option.. maybe even less wood.. Do you have cabinets or anything hung to the walls?