EPS foam in pole barn

[Dstyduhar]

Want to put 1.5" EPS foam between the girts in my barn. Was considering XPS but the price is crazy right now.

The building has double bubble between the metal siding and framing with reflective side out. This EPS foam is also faced with a reflective side. Would the reflective side also face out? I'm not seeing unfaced EPS. I cant seem to find an example of a wall buildup where there are two layers with a reflective face.

Any downside to using EPS?

Thanks,

Drew

 

[Firebrick43]

Are you leaving it exposed?

 

[Dstyduhar]

I framed 2x6 walls between the posts.

I guess the wall stack up would be double bubble > eps between girts > R19 in wall and osb or something on inside.

 

[Dstyduhar]

Lowes have 1.5" EPS for 22 bucks a sheet so not bad. Wonder if a guy could remove the reflective facing? I see pics where its already peeling off so who knows! Also on the hunt for used XPS

https://www.lowes.com/pd/Common-1-5-in-x-4-ft-x-8-ft-Actual-1-4375-in-x-3-875-ft-x-7-875-ft-R-Expanded-Polystyrene-Foam-Board-Insulation/3362408

 

[Firebrick43]

There is no reason to remove it. It’s immaterial to your situation. If you were leaving it exposed (which it is a fire risk so I wouldn’t suggest it) it would be advantageous to put the reflective side facing in.

Reflective barriers only work if it can reflect into an airspace. Since you are putting fiberglass to the inside it doesn’t matter.

 

[Natty Bumppo]

I insulated my entire pole barn using Polyiso that I found on Craigslist or FB Marketplace from a distributor selling factory seconds or used 4x8 sheets. I know you're looking for EPS...but I bet there's somebody selling used or seconds near you. It was about half the cost of a brand new sheet. And most of it looked brand new.

 

[Dstyduhar]

Yeah I've been keeping my eye out for seconds. What im finding is pretty rough though. Those 2x2 frame metal buildings are popular here in NC and you can get 2" EPS and polyiso all day long for those.

Hell, if a Mernards were closer I would already be on my way @ 16 bucks a sheet for EPS https://www.menards.com/main/buildi.../1632105/p-1444435971090-c-5779.htm?exp=false

@Firebrick43 - I understand your comment about the reflective barrier if its exposed. Is the reflective barrier on the double bubble even serving any purpose if it's just covered by metal? Should they have installed it with reflective facing in (not knowing I would build out the wall)?

Thanks guys.

 

[Firebrick43]

Yeah I've been keeping my eye out for seconds. What im finding is pretty rough though. Those 2x2 frame metal buildings are popular here in NC and you can get 2" EPS and polyiso all day long for those.

Hell, if a Mernards were closer I would already be on my way @ 16 bucks a sheet for EPS https://www.menards.com/main/buildi.../1632105/p-1444435971090-c-5779.htm?exp=false

@Firebrick43 - I understand your comment about the reflective barrier if its exposed. Is the reflective barrier on the double bubble even serving any purpose if it's just covered by metal? Should they have installed it with reflective facing in (not knowing I would build out the wall)?

Thanks guys.

It is debatable for the double bubble. There is some air space there as there are ribs of the metal so it can have some effect for heat rejection, but not like it would if it were spaced a few inches from the wall.

Double bubble is nothing more than a condensation blanket, and it does that without doubt so it doesnt rain inside when there is wild temp swings.

If one was to force heat an uninsulated building in the winter with a salamander heater or similar, the reflective layer would be advantageous to the inside somewhat

Most of the R value claims that the double bubble manufactures make are pure lies. At this point why worry about it. If you are putting foam between the girts (which is awesome) its immaterial past that point. The only disadvantage of eps vs xps in walls is that mice will do more damage to it if they can. Not that they cant chew up xps as well its just more difficult to do so.

Polyiso if you can find it is much more fire resistant than xps and eps.

 

[jack stand]

^^^^ and the highest r value per inch.

 

[Dstyduhar]

I can find 2" poly easily (metal buildings) but 1.5" seems to be elusive!!

I thought Poly loses R value over time and when cold?

 

[Firebrick43]

I can find 2" poly easily (metal buildings) but 1.5" seems to be elusive!!

I thought Poly loses R value over time and when cold?

All foam looses r value over time as the gases they use to blow the foam beads or cavities looses value over time. Depending on which gas the use depends on how much, the cell structure depends on how quickly.

Poly iso and xps take several decades or more for that to happen. EPS because of its cell structure happens in a very short time, more than likely before it’s even delivered to you so the end user doesn’t see it because it’s already happened.

So in 10 year xps is minimally better than eps and polyiso probably after 20 will still be 0.5 to 1 r value higher than eps per inch but initially will be almost 2 R value points higher.

Of course differences in rodent and fire resistance will still be there over eps.

This isn’t to say eps is bad, I have nearly 6” of it on my ICF walls and it’s great but I do have to mind the %*%#*^ rodents

Even though fiber glass is so lousy in comparison to other insulation types in every metric other than installation ease it has a place and can be quite effective depending on how the builder uses it and how the buildings owner uses and heats it.

 

[billconner]

Have you considered rigid Rock wool. Site says it's available 1 1/2" thick and R6 forever. I'd guess not in stock at big box stores but should be available. Would not require covering for flammability. I have not found pricing but would seem less than foams. Just a thought.

 

[Dstyduhar]

I have not but anything mineral wool is through the roof on price that I have seen. I've been looking at those 8ft fiberglass batts for post frame and thinking about hack those up to save money, haha.