Any advice/input on my strategy for insulating a cold rolled building?

[zippyslug31]

I've been thinking about how best to insulate the interior space of a cold rolled "kit" building. I'm mainly trying to avoid all the condensation problems I've read far too much about. I'd love to hear some feedback on my current plan.

The building:
30x26x8, cold rolled steel, ceiling to remain open/vaulted, fully open interior/ no interior walls. This building will be a workspace for the wife; nobody living in it full time. Heating and cooling via a minisplit or something similar. Yes, we get hot in the summer and cold (and snow) in the winter.

Insulation strategy:
I'd be insulating the exterior tin away from the frame structure, basically taking what I learned from this site. This information shows the following detail for exterior tin insulation:

View media item 110089
Once the metal work is complete, I'd frame out the interior walls for:
(1) support of un-face, primary insulation layer, then (2) gives me a stapling surface for vapor barrier to cover the insulated walls, and lastly (3) I'd likely panel over this vapor barrier for the completed interior wall surface.

The ceiling would not framed but to support the batts I'd use banding/webbing attached to the roof structure (trusses, purlins, whatever I can attach it to). Over that, vapor barrier. There would be no real reason to cover the ceiling for any "finished" look.
As an alternative, I might just insulate with faced batts (supported using the same band strategy, of course) and call it good.

Does my strategy hold water? If so, maybe I need a better vapor barrier!

 

[readhead]

Thermal blocks are only used with SSR roofing. You are way overthinking this. Have you talked to any metal building insulation companies? There are a couple of common insulation systems that will work for you. If you place girts at 2' on center there will be no or very little need for framing inside.

 

[hilld]

Why not closed cell spray foam? Worked great on my pole barn tin.

 

[zippyslug31]

Thermal blocks are only used with SSR roofing.

Not according to the link I posted.

If you place girts at 2' on center there will be no or very little need for framing inside.

The point I was trying to make regarding the framing is that it's not only for the insulation, but as much to create the structure for the internal walls. Nothing crazy; probably 24"OC. Just something to hang panels and/or support for shelving. The design of the kit provides a good plane in which to attach the external tin, but not for internal sheeting material.

 

[zippyslug31]

Why not closed cell spray foam? Worked great on my pole barn tin.

A few reasons:
- I'd like to keep it DIY as much as possible.
- Most say that if you ever need to remove/replace an exterior tin panel, you're in for a world of hurt since the spray foam doesn't allow the tin to release without a fight, and you're generally left with having to redo the foam in that space.
- Assembling the building with metal-to-metal (skin to columns) contact and then spraying in the foam in the voids does nothing to counter the transfer of the outside temp into the conditioned space. If you have a traditional wood pole barn, you don't have this to contend with as much since the wood poles aren't good heat exchangers. I also have a wood pole barn and wouldn't worry much about insulating it this way, but this metal kit has a different set of problems to deal with.