isulating a steel building

[Farmallgray]

This is my first post here. I found this site a few weeks ago and it looks like there is lots of good info here.

I collect and restore antique farm and garden tractors. I built a 50'X72' building for storage and workshop space about 6 years ago. This is an ongoing (as the budget allows) project. 2 years ago I ran 200A electric service to it and this fall I concreted 1/3 of it (24'X50') to be my workshop. I put pex tubing in the concrete for radiant heat.
My next step is to start insulating and sheeting the work shop area and building a partition between it and the storage section. I'm including a pic from when we poured the concrete. You can see how the girts and purlins are layed out in the pic. It is a web truss building similar to miracle truss brand. It uses horizontal 2x6 girts and verticle 2x6 purlins all on 2' centers. So I have 5-1/2" of space for insulation. My initial plan was to use 6" fiberglass bats or rolls in the walls (sheeting with OSB) and that plus 1" foil faced foam board in the ceiling. That would give me R19 for walls and R26 for the ceiling. That is a liitle light for a house, but should be satisfactory for a shop. I am open to other suggestions for insulation. I'm wondering is I should use insulation with the paper facing, and should it be toward the inside of the building? I'm concerned about condensation behind the isulation. I'm also wondering if I should look into the foil/bubble insulation either instead of or in addition to the fiberglass. Sorry for such a long post.

 

[rodnok1]

There is a chance of condensation against the steel that's for sure. I would use the faced and it should be fine. Without the facing it would let moisture through and condensate on the steel. I've thought about using foam everwhere and covering it inside with poly the wallboard over that.

 

[mhoffm911]

Faced insulation is normally installed towards the interior (heated) space.

 

[kbs2244]

They sell a fiberglass with a white poly face on it just for steel walls.
I belive you get a roll of wide tape to seal the edges.

 

[D KRAGER]

I'm working on insulating my pole building right now. I was also concered about moisture getting trapped in the wall. So i decided for now to put cheap styrofoam between the perlins against the tin. Later I'm studding out the walls and will use fiberglass or cellulose don't know witch to finish it off. This way the fiberglass or cellulose will not come into contact with the tin, and I don't think condensation will be a problem.

In your case you could lay foam against the tin, then you still have enough space to use r-13 fiberglass to finish the void.

 

[Palf]

I had my shop insulated with the industrial spray in stuff. No moisture will build up between the outer panel with it. It cost a bit more than the sheet or fiberglass roles, but I liked how it owrked in my friends shop, so I went with it also.

 

[sctattooer]

The better your vapor barrier is on the INSIDE, the less chance of moisture in the wall. I'd recommend unfaced fiberglass, then cover the whole thing on the inside with plastic sheeting, and make sure to tape the seams and overlap them a bit.

 

[Farmallgray]

I'm working on insulating my pole building right now. I was also concered about moisture getting trapped in the wall. So i decided for now to put cheap styrofoam between the perlins against the tin. Later I'm studding out the walls and will use fiberglass or cellulose don't know witch to finish it off. This way the fiberglass or cellulose will not come into contact with the tin, and I don't think condensation will be a problem.

In your case you could lay foam against the tin, then you still have enough space to use r-13 fiberglass to finish the void.

What type of styrofoam did you use?

 

[Farmallgray]

The better your vapor barrier is on the INSIDE, the less chance of moisture in the wall. I'd recommend unfaced fiberglass, then cover the whole thing on the inside with plastic sheeting, and make sure to tape the seams and overlap them a bit.

So the warm moist air on the inside can't get through the vapor barrier to condense on the tin. That makes sense now.

 

[D KRAGER]

I Just Used The Expanded Styrofoam (white Cheap Stuff). Also Yes I Will Put A Vapor Barrier On The Inside When I Get Done Studding It Out, But For Now The Budget Only Allows The Styrofoam.

Even If You Put A Vapor Barrier On The Inside, I Was Still Worried That The Tin May Condensate, Maybe It Won't. Another Reason I'm Doing It This Way Is What I Said Above, Budget Right Now Is Tight.

You Know I've Been Asking Around About How To Properly Insulate A Pole Building, I've Gotten All Different Kinds Of Ideas From Different People. I Don't Know If There Is A Perfect Way. The Reason I Say This Is Because A House Can Breath Somewhat To The Outside Thru The Plywood, And Even House Wrap Is Made To Let Water Molecules Out. With Metal Siding No Moisture Can Pass Thru The Tin, Thus If You Get Moisure In The Wall It Can't Get Out. So I Guess We Need To Keep All Moisture Out Of The Wall!!

 

[locoman]

Do a google for p2000 insulation. It's a little expensive but very good stuff. I just toured 1 mil house build that was done with it.

 

[Farmallgray]

Do a google for p2000 insulation. It's a little expensive but very good stuff. I just toured 1 mil house build that was done with it.

That is interesting stuff. If it does what they say it would be great. It looks like it would be really easy to install in my application. Does anyone else have any experience with it?

 

[kxmotox247]

The better your vapor barrier is on the INSIDE, the less chance of moisture in the wall. I'd recommend unfaced fiberglass, then cover the whole thing on the inside with plastic sheeting, and make sure to tape the seams and overlap them a bit.

This is how they built my polebarn. And they gave me a heck of a warranty too so they must have some confidence in this technique. R-19 blankets 6" thick - 8' wide. Covered with visqueen and sheeted in white ribbed steel.