Home Forums Hunting & Shooting Hunter's Campfire Proper steps in insulating a pole barn

I find that apparently simple processes are more complicated than they look. So, please help me understand what it necessary and important in insulating a pole barn.

I have a wooden structure, with metal walls and roof. When it was built, rigid insulation was installed in the roof. That was pink rigid foam with a foil face towards the interior.

Now I want to insulate the walls and I have a couple of questions to sort out.

It seems that (R for R) white Styrofoam boards are half the price of rigid pink foam boards. In other words R6 Styrofoam is about twice as thick as R6 foil-faced pink foam but half the price. Is there a down-side to using the Styrofoam?

I expected to make the insulation airtight by metal-taping all the joints. But someone suggested I need a vapor barrier like visqueen (?) on the interior side of the foam insulation. Do I need the visqueen? It seems like the building materials are engineered to ventilate the backside of the foam through the vertical ribs in the metal siding and the open venting at the eaves and ridge.

I will be putting fiberglass panels (Like in commercial bathrooms or kitchens) over the insulation as my interior wall. I'm choosing that over anything else because 1)I can get them free, and 2)they seem fairly durable, waterproof and light-colored and somewhat reflective.

This seems simple enough until I get ready to dive in to it and then I wonder if there is something I still need to consider.

So: Styrofoam between the stringers, metal tape at joints and edges, fiberglass pre-drilled for ring-shank nails into the stringers, silicon caulk at the edges of the fiberglass panels. Can it be that simple or am I setting up a problem there?

So it is twice as thick per r value which means it isn't as good of an insulator. If you have completely fill your space with insulation, the rigid foam will provide more insulation power. I have not really used the stryofoam, but the one sheet I had was fragile, crumbled fairly easily, and looked to be easy pickings for mice and other vermin to make a home in. The rigid foam is pretty strong stuff.

IMO you are engineering an excellent job. Some might call it overkill for a pole barn, but as you outlined it should do a really good job. Have you compared the price of spray-on insulation to what you are planning? It is far better but a bit more costly. You have to decide if the difference in cost is worth it to you.

little white beads turn into a mouse playground....

I would look at one of two ways. Urethane foam is really good stuff and the shiny part you get on the inside acts as it's own vapor barrier. Either of the products I am recommending can be used for walls and ceiling. Don't mess with the other stuff.

The other is called metal building insulation. They can run it for you as wide as necessary so you have exact fits between poles and it comes with it's own vapor barrier, most people prefer white, as it makes the inside of the building brighter.

I'd certainly stay away from bead board, or the blue or pink foam. Not that the blue or pink is a bad product for the proper applications I just don't consider metal buildings that. Get two or three bids either way you go.

Are you keeping animals in this barn? I think Styrofoam can be hazardous if they eat it because it doesn't break down and can cause obstructions/choking.

No animals, except maybe a dog for company when I'm out there.

Cost is a primary consideration.

The Styrofoam I would use would about fill the space between the stringers. The pink board would only fill about half the depth.

One end of the building will be built out as a gun room with a built up floor of plywood over insulation over visqueen over the slab.

The majority of the space will be multi-function workshop: auto shop, machine shop, etc. sharing the floor space.

I wonder if mice are a factor or not. The building seems to be quite tight, it's been up several years and I've never seen signs of a critter in it. And the walls will be pretty tightly built. Maybe I should use the pink foam on the lowest tier and Styrofoam on the rest?

I'll see what else I can learn about the other materials mentioned.

Thanks!

I'd spray it.

Correct> Urethane foam. Best way to do it.

Does that eliminate putting the panels on the wall?

For a barn, i wouldn't put those panels up. You likely will want something a bit nicer in the gun room. The spray urethane is sort of a tan creamy color, firm surface, and it's own VB. If you want it brighter (very few barns and shops have adequate lighting, IMO) rent a sprayer and paint it white.

Spray would be the best insulation, best VB, most expensive, etc. get a bid and price out your labor on cutting endless foam panels up. Pole barn will have mice regardless of what it 'looks' like, no way to stop them. Factor in how much you plan on heating it and how long you plan on keeping it.

Okay. You've all got me thinking. Thanks!

First of all, spray foam is out. It is out based on cost but it is especially out because I am going to do this in stages over time.

It is not a barn in the farm sense. More like a very large garage (30' x 40' x 12') and I want finished walls.

Maybe I need to be disabused of my first thoughts on how to install rigid foam. I was going to cut pieces to fit between the stringers, and mount my interior wall material directly to the stringers. (Stringers? Is that the right name for the horizontal 2x6s the metal exterior is nailed to?)

Would I be better off to mount the foam board over the face of the stringers and the interior wall material directly on top of the foam board? That would leave a big air gap between the insulation and the exterior metal. That seems like an inviting space for all sorts of vermin, doesn't it? But it might make a firmer wall.

Use the Dow board, cut it to fit tightly, tape it with Tyvek tape, cover with FRP panels. You have the right idea. You can glue the FRP panels to the Dow board to keep them tight. You will want some mechanical connection to the barn, however.

The foam board insulation at R6 isn't much insulation. You may not notice a big difference. It helps if you can have a space of dead air between the R6 and the outside walls though.

R6 ain't squat...

Barndaminum finish it... build a 2x4 wall, fill wiht R30ish glass batt....

Who said you had to spray it all at once. I am doing my house now in stages. $1.10 sqft closed cell 2" thick. Save up, do an area. You will never get any of the processes you talk of now to be anywhere near as airtight as spray foam and if you can't keep it airtight, you are wasting your heating/cooling dollars.

No one has mentioned (or I missed it) blown in cellulose insulation. It is treated to be fire retardant and bug retardant. I can't speak to the price, but the big box stores let you use/rent a blower when you buy insulation from them. Said to be a great insulator. miles

Dennis, Are you agreeing with putting the Dow board between the stringers or over them? By mechanical connection, are you meaning something other than taping the stringer/Dow Board joints?

Rost, et al, Yeah, R6 ain't much. But I won't be in there much, if at all, in the winter. This won't be heated unless I am forced to work on one of the cars or something, in which case the heat will be a woodstove. Alleviating the solar oven effect in the summer is as big of a concern as heating.

The gun room will be heated but I'm looking for a way to control the temp to only stay a few degrees above the rest of the barn to keep condensation out. I figure that's the same principle as a Golden Rod or light bulb in a safe.

How much waste will you have with the cut-to-fit panels? Figure that in the price as well.

I'd have someone squirt an inch (or more) of urethane on the walls then paint it. You can then spray latex or most of the guys have some good coating options.

You won't beat the spray-on for dollars per R-value. The initial cost can be a shocker but either pay now or pay forever. 3/8"-1/2" sprayed on will blow R6 panels out of the water.