Metal Building - Blow in insulation question

[Deude_Mann]

So I have a metal building with horizontal girts (beams) on the walls and purlins on the roof. The center-to-center spacing on the wall girts is roughly 4 feet, and for the roof it is roughly 5 feet. The girts/purlins are 6" deep so this would be an R-19 thickness of insulation.

I want to use blow-in insulation to fill the space in the purlins, and then cover that with metal panels, like R-Paneling, screwed into the girts and purlins, just like the exterior. So I am thinking I would use the usual mesh to cover the girts and purlins to hold the insulation in place until I get the metal panels screwed on. I would like to attach the mesh to the purlins and girts with double-sided tape or the like.

So the question is, can the mesh deal with that much span between support points until I get the panels on?

If the fiberglass bulges a bit, and I end up using extra, then no big deal as long as I can still get the metal panels on. I would like to avoid adding intermediate blocks/studs.

I know I can also get wide batt and go that way rather than blow in, it's just blow-in is another option I can consider.

Before anyone brings it up, I am completely sealing the exterior panels and am in a region where I don't need an additional vapor barrier.

Thanks

 

[Deude_Mann]

This is what I mean by mesh and blown-in insulation. This is what was used in my house. It would be fiberglass, not rock wool or cellulose.

 

[purediesel]

why not spray foam?

 

[930dreamer]

I'd try to do spray foam if you can. My friend had his shop in Amarillo done and I couldn't believe the temperature difference inside.

 

[readhead]

Use the mesh and then banding to support the mesh. It is a great option that a lot more people should consider.

 

[MetalBuildingFun]

Before anyone brings it up, I am completely sealing the exterior panels and am in a region where I don't need an additional vapor barrier.
Thanks

Why do you not need a vapor barrier? Your metal building will sweat with the temp changes from day to night. Your insulation will get wet and you don't want that.

I went down the rabbit hole on insulation for a metal building before we had ours built. I am quite happy with what we have used and I am not going to try to sway you one way or the other. What I will do though is to ask you to do some more research regarding the radiant barrier to protect whichever insulation you do decide to go with.

One thing I would encourage you to do though. Even if you think you don't need the radiant barrier, get it anyway. Why? Because you put that in before you add any spray in insulation and when you need to do any repairs to your outside metal parts you can easily remove them.

 

[Deude_Mann]

why not spray foam?

Too expensive per board foot, 3X-4X for what equivalent R-value custom cut and covered batt insulation costs.

 

[Deude_Mann]

Use the mesh and then banding to support the mesh. It is a great option that a lot more people should consider.

I seriously considered it but went with lined custom cut batt insulation from Bay Insulation.

 

[Deude_Mann]

Why do you not need a vapor barrier?

The metal building exterior is sealed up, and the inside is (will be) climate controlled. In fact Bay Insulation (big company) advised me to x-cut the material that they cover their batts with so it could breathe to the interior. Otherwise I'll have a double vapor barrier (exterior and interior).

 

[readhead]

Good choice. It should work out well.

 

[86turbodsl]

If you can at all swing it, do spray foam. Anything else is a lot of screwing around for little benefit.

 

[86turbodsl]

Too expensive per board foot, 3X-4X for what equivalent R-value custom cut and covered batt insulation costs.

Batt insulation has convection currents in it that makes it significantly less actual real R value than the alternatives. I have a house with spray foam. It's 3000+ square feet. I heat/cool with a 36000 btu heat pump. the ROI is pretty quick on that kind of efficiency.

 

[misterfixit]

Too expensive per board foot, 3X-4X for what equivalent R-value custom cut and covered batt insulation costs.

I'm in the process of building metal shop building myself near DFW. I've talked to several insulation folks and I understand you don't need the same R-value with foam that you would need with fiberglass. From what research I have done, R-value in foam is pretty meaningless.

I'm planning on 1.5" of closed cell foam in my building, which should be about R-7 on the scale. However I have several friends with buildings and the same insulation who will swear the value is equivalent to at least double or triple.

 

[Deude_Mann]

Rock on with your closed cell foam guys. I'm going with the batt.