Insulating My Pole Barn - need help

[JerryK]

Don't know about a vapor barrier. A pole barn has a lot of moisture in the winter with vehicles/tractors/people tracking in and out/etc. There is probably not many pole buildings that don't leak a little water thru their lifetime. The moisture has to go somewhere, so I would not try to make it too tight.. In my barn, when the roof has a foot of snow on it, the moisture forms as frost on the bottom side of the sheetmetal roof, then when the snow slides off, the frost melts and rains down a little onto the top of the foam panels. The only way you can stop that is to insulate directly onto the roof sheetmetal bottom. But you would still have to have a false ceiling insulated to keep the heat closer to the floor. The under the roof insulation would make it hard to locate leaks in the metal roof, if you ever got any. You can spray foam under the roof, but that isn't cheap either. You can get frost on the bare walls, too. But it does not take much of a barrier to keep that from happening. The foam or even a sheet of chipboard would probably stop that.

 

[steveessie]

I recently insulated and finished my pole barn. You didn't mention what you are doing with the ceiling, but the ceiling insulation is more important that the walls. I put a vapor barrier under the trusses, followed by metal liner plate, then blew over 6 inches of celllulose in the ceiling.

For the walls I bought some used polyiso (high performance foam insulation) from a roofing company and fit that into the walls. Styrofoam is not great insulation. If I had it do over and didn't have the polyiso available, I would put cellulose in the walls. Put tyvek or some other building wrap against the girts, put a vapor barrier over the inside of the poles, add drywall/OSB/Metal panels/etc on the inside, leaving a gap at the top that can be closed after blowing the cellulose into the wall cavity.

Cellulose is the most cost effective insulation out there and it's super easy to blow in.

I am in the process of making a drop ceiling at 9ft (originally ceiling is 15 feet - so there will be a space between the original ceiling and my drop ceiling). I studed between the joists for my ceiling and am in the process of laying kraft-faced fiberglass insulation R11 - it is cheap and will at least hold in some of the heat. I am more concerned about the walls and if I need a vapor barrier. I will use the polystyrene, simply because it is cheap and pretty hassle free. Do I need a vapor barrier with polystyrene?

Half of the garage is going to be uninsulated (30x30) where I park my cars, trucks, toys, etc. The "heated" part (the other 30x30 I am insulating) will be used for the kids to play in and to do regular vehicle maintenance when it is too cold in the winter.

So, do I still need a vapor barrier in the walls of the insulated part if I use polystyrene between drywall and metal?

 

[JerryK]

I would say no... you want the insulation and everything to breathe as much as possible.... You have a lot more moisture in that barn than a normal house... [ but, then again, I am just an old uninformed retired furt... ]

 

[KennyG]

I'm going to say use the vapor barrier. I've never seen an effective insulation system without a vapor barrier. The vapor barrier should go next to the heated space. I doubt you will get the styrofoam to ever seal well enough to form a barrier and that pretty well ruins the insulation value.

Being as far north as you are, condensation won't be much of a problem since the siding will be naturally ventilated anyway. I never saw condensation in my pole barn before I finished it. Be sure you have roof vents and a way to get air above the finished ceiling. In any event, I wouldn't put the foam directly against the metal because it won't be really against it. There will be all kinds of spaces to trap air/moisture.

I don't mean to start an argument (although that happens to me often) but I think you need to look carefully at the cost and results you will get. Cellulose almost has to be cheaper than styrofoam. I put about 6 inches of cellulose in my 40x48 pole barn attic for about $300.

How did you do the drop ceiling? I'm having trouble seeing this. How are the new joists supported?

 

[Murfster3]

I have a 32 x 40 pole barn that I installed a metal ceiling and I put blown in fiberglass insulation in the attic around 2'. The walls I installed a plastic vapor barrier then used blown in fiberglass insulation. The thing was I picked up bags of it at lowes in the summer for $9.99 a bag. It's usually priced at $30 something a bag plus you can use there machine for free. I have 2 vent free furnaces that heat it and it stays 50 degrees on the lowest setting

 

[steveessie]

I have a 32 x 40 pole barn that I installed a metal ceiling and I put blown in fiberglass insulation in the attic around 2'. The walls I installed a plastic vapor barrier then used blown in fiberglass insulation. The thing was I picked up bags of it at lowes in the summer for $9.99 a bag. It's usually priced at $30 something a bag plus you can use there machine for free. I have 2 vent free furnaces that heat it and it stays 50 degrees on the lowest setting

Did you install the vapor barrier closest to the metal or did you attach it against the framing you would hang drywall from? Which order was it:
metal, plastic, blown insulation, plastic, drywall (or OSB)
or
Metal, blown insulation, plastic, drywall (or OSB)

 

[Murfster3]

Did you install the vapor barrier closest to the metal or did you attach it against the framing you would hang drywall from? Which order was it:
metal, plastic, blown insulation, plastic, drywall (or OSB)
or
Metal, blown insulation, plastic, drywall (or OSB)

It was metal, insulation, plastic and then osb.

 

[Aquamoose]

I am very intrigued by the feedback left as I'm in a very similar position with my 36 x 48 shop. Thus far, I've got the ceiling covered with OSB and already have radiant floor heating in place but not hooked up yet. My plan was to blow in insulation at the top (nothing else up there) but with air dams/gaps at the ends to allow cold air in the attic space. Originally I was going to stuff "Brillo pads" (for the life of me, I don't know what else it's called) in the inside gaps at the bottom where the outside steel panels and the base caps meet to deter critters. My plan after that was to put up bat insulation but reading some of your comments, I'm surprised to see suggestions of cellulose as insulation as a cheaper alternate.

 

[Gunny]

I can't see how putting some Tyvek house wrap could hurt anything, since it would be a both a vapor barrier and cut down on air movement, but I don't think I would want cellulose up against the metal. I would think it wouldn't take too long for condensation to soak it through. Ideally, in that case, you would put the Tyvek wrap on first, but then you'd have to frame up a stud wall and cover that to be able to blow in the cellulose and that's getting expensive and a lot more work.
The house wrap could be stapled up then the Styrofoam placed directly over that and seal the seams with tape for more airflow control. I would also recommend that you at least cover the bottom 4 feet of Styrofoam with some OSB to keep from getting holes knocked in it.

Like said above, the ceiling is the most important thing to worry about when keeping heat in, the walls would be pretty much good to go with less insulation as long as you block the airflow.

 

[mehig]

I've seen insulation for use in metal pole building that looks like/is bubble wrap. You put it up first and then put the metal over it.

 

[srs]

Steve, here is a link to the Morton Building website, some info here as to how they insulate their buildings.


Our Features - Energy Performer® Package by Morton Buildings, Inc.

 

[BuilderML]

Hi Steve,
The moisture in the air you are worried about comes from warm air. A vapor barrier needs to be installed on the warm side of the wall and or ceiling to stop the vapor from getting into the wall cavity. Tyvek is NOT a vapor barrier. Use a 6 mil poly as a vapor barrier and make sure you seal it to the floor with a draft stop caulking and tape all your seams with a builders tape. Any holes in plastic will allow moisture to go thru.
Steve i am sorry to say but i think your looking at this the wrong way. I am not trying to be rude by saying this but if your not going to do it right do not do it at all as it will come back and bite you in the end. When building something it will NOT be cheap only thing i can say is that your budget was figured wrong so do not try to cut corners or buy cheap materials to "just get it done".You will only waste your money. Styrofoam should be kept to make coffee cups and thats about it. Now with your project i would hold off until you gets the funds to do it right.
Here is what i would do:
1) Use a closed cell spray foam on walls and ceiling min. of 2.5 inches will allow you not to worry about the vapor barrier as the thermal break happens within the foam itself you will have no condensation issues.
2) You can spray right onto your metal panels but that will cause problems if for some reason you would need to fix or replace a panel due to damage in the future. If your not worried just spray right over.
3)Cover the foam with what meets your local building codes as it is very flameable. You may be able to just spray a fire resistant paint over the foam if it is allowed in your area.
Yes it is expensive but like i said save yourself problems in the future.

Good luck Steve
Like i said i am not trying to be rude just be wise when spending your money.
Talk to a reputable local contractor or building official and get his input on your project for your area

 

[Jnasystems]

I am in a similar situation. I have a 32x42 metal pole barn and found a guy that sold me 400 sheets of 4x8 2.5" thick styrofoam insulation. The plan was to install it in 2 layers to give me 5" everywhere. There was some fiberglass insulation already there - about 2" thick. I figured that I would get to about R30 over all. So with that said, what is wrong with styrofoam? I do plan to put up some plastic after the insulation is all in, but I didn't have plans to cover that at this point - maybe one day. Am I creating a fire hazard? Will there be damage done to the building that I haven't thought of? Does it need to have a fire barrier right away? I don't have much in it at this point since I got the foam for $300, but if there is excessive risk, I can still change direction.

Thanks

 

[BuilderML]

HI Jnasystems
One of the big concerns with using foam is how toxic the fumes will be if fire is ever present let alone the fact how fast it will spread. The fumes will take you out in seconds. Leaving plastic exposed will do the same thing if a fire is ever present. They do have a plastic made for applying over unfaced batt insulation that is fire retardant and is used in applications when no wall covering will be used. Sorry i can't comment on 5" of styrofoam it is not a practice i have ever used and i don't want to give you the wrong info.

 

[KennyG]

Definitely you need to get a good fire barrier as soon as you can, but that goes with any foam. My biggest problem with styrofoam is that it's not very consistent (which is why it's cheaper) and it's hard to cut and get a clean edge which makes it hard to get a good seal between the sheets. Work with some polyiso (which has almost twice the R value) and you'll see the difference. That said, you've got it and you got a great price so go for it, but plan on putting a sheet plastic vapor barrier on the inside and then cover it with a fire barrier. You can't leave the plastic or foam exposed permanently. That's just too dangerous.

We've talked about the inside finishing before and drywall, OSB, and metal liner panel all have their advantages. If you're not wired or adequately wired already, think about doing all your wiring in conduit on the wall surface. It will make fitting the foam panels a lot easier and give you a better seal. I learned this the hard way.

 

[yanmars]

I will start by saying this may not be the correct way but this is how I did mine. I have a 40x81 Cleary building. It has a 1 foot ventilated overhang all the way around and at the peak a continuous cap to let the warm air out.
I got about 3500 square foot of used rigid foam roof sheeting, 3 inches thick for $300. I cut the 4x8 sheets to fit between the ceilings nailers 2 foot on center. I used screws in the nailers to hold them up but I cut them so close to size that they nearly held themselves in place.
I got new offals of Pink Dow rigid foam in 1/2 thick. On the side walls I attached them the same way but in two pieces for 1 inch thick. I staggered the seams. I did my 5 overhead doors the same way. The side wall insulation was under $150. The screws were fairly expensive but overall I think I had about $600 total in the project.
I did this because on a few days it would rain inside. Condensation formed on the bottom of the cold roof and then would rain down. Now maybe it just rains down on the rigid foam and is making a mess in there, the hope was there was enough insulation to avoid the condensation. The building certainly is more uniform in temperature and certainly cooler in the summer. I have a dirt floor at this point and no heat or electric in it.
Certainly not saying it is right, only how I did it. If a problem it would not be hard to remove, take the screws out.

 

[zmansmac]

When I moved to my present house in SE Michigan 11 years ago the 24 x 32 x 12H pole barn was going to be my new woodworking shop, so it had to be insulated so I could use it year round. I happened to get a good deal on some "seconds" plywood to keep costs down. I nailed 3/8 thick to the ceiling and screwed 5/8 thick to the sides after putting in 6 inch fiberglass insulation on the sides. I blew in about 12 inches of cellulose in the ceiling. But I did make an access hatch with 4 inches of rigid foam. In the two front sliding doors I glued 2 inch rigid foam between the 2 x 4s. And then I mounted sections of the garage seal stripping on the inside by the sides of each door and along the top (this also helps keep even small critters out as I have never even had a mouse inside). Drywall could be used for the ceiling and sides but the plywood worked better for me since I have all kinds of bins, parts cabinets and wood racks mounted to them. The insulation was all purchased at the same time I added some fiberglass and cellulose to the main house and so was able to claim it as an energy credit. I have a small ceiling mounted Reznor natural gas heater that doesn't have to run to often to keep it at 62-64 degrees in the winter. The other plus is on a 90 degree summer day it stays in the low 70s as long as I keep all the doors closed. I did not add a vapor barrier and have not had a problem with humidity. And after all the plywood was up I sprayed the sides and ceiling with white paint. My ten double 4 foot florescent fixtures give plenty of light with the white paint.