Pole Barn Insulation -- Foil and Fiberglass

[therick34]

I'm new to the forum and have a question that a few hours of searching the archives hasn't been able to answer.

With any luck, I'll be getting close to putting a new roof and slab in an existing pole barn this summer. I'm settled on the choices for those two things, but need to decide what to do for insulation in the walls. I know that condensation is a concern with pole barn insulation and I also know that spray foam is a solution. That said, spray foam isn't in the budget.

I was researching solutions and found this for a retrofit solution: http://www.insulationstop.com/post-frame-pole-barn-retrofit-wall
Obviously that's not enough insulation here in Michigan, but would an acceptable solution be to use the double bubble foil over the purlins, taped and sealed, with a layer of fiberglass bats (vapor barrier or not?) and then finished to the interior with OSB, plywood or sheetrock? Seems that the foil should combat the condensation issue, but I know that vapor barrier on the cold side is opposite of standard practice in a cold climate like mine.

I'm still a few months away from having to decide, but figured someone here might have an answer.

Thanks in advance!

Rick

 

[Highbeam]

Skip the bubble wrap.

Regular fiberglass is standard and just fine in this application. There is no reason that the FG can not touch the metal. Once you insulate and then install the vapor barrier on the warm side, the moist indoor air will not be exposed to the cold metal siding which is where the condensation comes from.

Do it like a house.

Have you framed between the posts yet? I'm doing the framing right now and it takes a long time.

 

[bullnerd]

Try finding some of the 8' wide rolls of insulation in your area.Then you dont have to frame out between the posts.Johns Manville is who Morton uses.

 

[BadgerBoilerMN]

The main reason for employing a vapor barrier is to protect the performance value of the insulation by keep moisture from wicking heat from within. The second reason is to prevent mold from growing.

All vapor issues result from the particular environment the building is in and the environment within. In cold climates we have to focus on vapor permeation and install the vapor barrier on the warm side of the interior walls for home construction. With humans showering, cooking and so on, too much moisture can lead to issues mentioned above. Most shops do not create a much humidity, so a vapor barrier on the inside is a questionable asset. Moisture permeation from the outside, especially through vapor tight steel siding is not the issue so much as airflow.

First, control the moisture from without with good gutters and drains, then rain screed exterior walls and try to keep the insulation you have from getting wet while avoiding a double vapor barrier that will not allow cycle drying between rain or wet weather events.

In most steel buildings the most common source of unwanted moisture, not to mention Radon, is through a slab. This is the most important place to install a proper vapor barrier to 0.10 perm.

Unless you have some source of moisture in your garage e.g. you forgot to insulate or at least place a vapor barrier below the slab, it is unlikely that you will need a vapor barrier per se. You want to keep vapor from condensing in the wall. This is a matter of your particular climate and the building's intended use.

You will note from the picture of the bubble-foil product that the foil was applied between steel and framing. This perhaps the the best way to make the building air/tight but there are cheaper ways that are every bit as effective. Attributing any meaningful R-value to bubble foil is a financial and engineering mistake all at once.

 

[winmck]

I used regular fiberglass and it made a huge difference. Pain in the booty to install but well worth the extra work.

 

[BadgerBoilerMN]

Try finding some of the 8' wide rolls of insulation in your area.Then you dont have to frame out between the posts.Johns Manville is who Morton uses.

This is a good tip. The Morton guy was out and showed me pictures.

I suspect it is a three man job to hang those big puppies...