Double wall pole barn, loose fill insulation?

[NitroGarage]

Location: OH

I'm planning out a garage build, auto/metal/wood workshop. 30-36w and 60 deep, roughly. Will have a lift, mezzanine, and possibly an upstairs office/rec center. 14-16' sidewalls.

I've been researching double 2x4 walls as they are the new "green" building trend but actually have been around forever.

I'm thinking pole barn, sheathed with osb, with a stud wall 10-12" to the inside of the poles and filled with loose-fill insulation. Outside sheathing to allow me to replace/repair a steel panel without needing to dump the whole cavity's insulation.

12" of insulation on a 180 linear feet of wall 16' high I'm looking at 2800 square feet if you figure it like a big attic 180 feet long and 16 feet wide, 12" high. 3000 square feet requires 180 bags not counting for losses in framing, let along the overhead door(s) and man door(s). 5 bucks a bag after bulk buying approximately and I've got the walls done for $900 (most likely less).

Inside is going to get studded anyways for drywall regardless.

R38 in the walls, planning on R60 in the roof.

Thoughts on this?

 

[Backyard Imports]

I bought my property with an existing pole barn that had only a dirt floor and fiberglass, opaque siding. I stripped all of the siding off, poured a slab, installed wall girts, stapled bubble insulation to those, and covered with metal siding.

I have since been framing the inside walls out with 2x6's, filling the cavities with loose "insulation", and covering with 7/16's OSB. This will allow me to replace the outside panels, if needed, without spilling insulation as you are concerned with.

It should be noted that I didn't do this from the start intentionally. I used the bubble insulation so that I had an insulation/vapor barrier that wasn't pleasing to the rodents and was very easy to install. (If I remember correctly, the bubble insulation has an R8 value.) It was only after the outside was shored up that I decided how I wanted to go about doing the inside. I don't know that I would do it again if I had a little bit more of forethought. I would probably just have used a house wrap under the metal as it would have served the same purpose and been much cheaper.

 

[cj7jeep81]

I'd be concerned with the loose fill settling over time. Eventually, you're not going to have any up top. Plus, that's a ton of floor space to lose.

 

[NitroGarage]

The insulation would fill the wall cavity from the attic, and essentially be self filling.

 

[Radix2]

Get a quote on having wet cellulose sprayed in there. The binder keeps it from settling or falling out and you get a nice tight pack.

it is really surprising how competitive insulation contractors are vs buying materials.

 

[NitroGarage]

I was just reading about the wet cellulose fill, I'll get a few quotes to see.

Yes, their buying power really comes into play vs "Joe Homeowner" even getting a bulk deal on dry blown in.

 

[NUTTSGT]

I see that you mention your location as Ohio. I'd suggest editing your USER CP and adding that location so it will always be there for future reference.

I'm not sure exactly where you are but locally but local to me is Advanced Fiber. They make loose fill cellulose insulation if that's what you would like to use. Perhaps a phone call might save you some cash per bag if you're close enough to make the trip.

http://www.advanced-fiber.com/

Also in NE Ohio, you can find Insulation King on CL who sells foil faced rigid insulation panels. Fitting rigid panels and sealing with some spray foam could give you a nice layer before you fill the cavity with cellulose.

 

[NitroGarage]

I see that you mention your location as Ohio. I'd suggest editing your USER CP and adding that location so it will always be there for future reference.

I'm not sure exactly where you are but locally but local to me is Advanced Fiber. They make loose fill cellulose insulation if that's what you would like to use. Perhaps a phone call might save you some cash per bag if you're close enough to make the trip.

http://www.advanced-fiber.com/

Also in NE Ohio, you can find Insulation King on CL who sells foil faced rigid insulation panels. Fitting rigid panels and sealing with some spray foam could give you a nice layer before you fill the cavity with cellulose.

Yep, just west of CLE.

I contacted Advanced fiber to see what they say. Thanks for the heads up. Not too far really.

 

[Fordman7795]

I bought my property with an existing pole barn that had only a dirt floor and fiberglass, opaque siding. I stripped all of the siding off, poured a slab, installed wall girts, stapled bubble insulation to those, and covered with metal siding.

I have since been framing the inside walls out with 2x6's, filling the cavities with loose "insulation", and covering with 7/16's OSB. This will allow me to replace the outside panels, if needed, without spilling insulation as you are concerned with.

It should be noted that I didn't do this from the start intentionally. I used the bubble insulation so that I had an insulation/vapor barrier that wasn't pleasing to the rodents and was very easy to install. (If I remember correctly, the bubble insulation has an R8 value.) It was only after the outside was shored up that I decided how I wanted to go about doing the inside. I don't know that I would do it again if I had a little bit more of forethought. I would probably just have used a house wrap under the metal as it would have served the same purpose and been much cheaper.

Standard foil bubble insulation has an R value around 1

 

[rburke65]

Yes....bubble insulation is not anywhere near 8. To the OP....get a price of having an insulation company doing this for you. I did and it was worth it for me to write the check.

 

[StevenMorgan]

Why not use tyvek building wrap before the metal instead of OSB sheething? that would hold the insulation back for the rare time you are replacing an exterior panel.

 

[Voi]

I'm thinking pole barn, sheathed with osb, with a stud wall 10-12" to the inside of the poles...

Not sure I'm following. How far from the inner most edge of your poles to the nearest edge of the sill plate of the interior wall?

Even if your sill plate was touching the interior edge of the columns you'd have over 10" of insulation in spots, assuming 5.5" columns and standard girts.

How deep will you columns be and are you planning standard or bookshelf girts?

I know one concern with really deep double walls is that the sheathing stays cold and condensation can freeze on the back side of the sheathing. I don't think that's typically a concern in Ohio but something to think about.

 

[Backyard Imports]

Standard foil bubble insulation has an R value around 1

That is certainly not what the manufacturer stated. But now that you said that and I looked closer at the docs provided with it, they are claiming R6 "if" it is used in a certain fashion. I.E. not installing it directly against the metal and leaving an air gap of a certain amount.

Either way, I was really just using it to keep the building from sweating. In that it worked great.

 

[matt_i]

Building a wall that thick is certainly "next generation thinking" imo, planning for when energy prices get to be double or triple right now. An R-30 wall (or better) would be quite formidable. Imo need special details to account for windows and doors, and I'd try to put some structure, even if tyvek or plastic vertical plane within the wall, bridging from inside to out, to prevent the entire wall-plane from being infiltrated by air. To make it work, you have to be just as forward-thinking about air leaks.

 

[NitroGarage]

Why not use tyvek building wrap before the metal instead of OSB sheething? that would hold the insulation back for the rare time you are replacing an exterior panel.

I've definitely thought of that, as long as it doesn't mess with condensation levels.

Not sure I'm following. How far from the inner most edge of your poles to the nearest edge of the sill plate of the interior wall?

Even if your sill plate was touching the interior edge of the columns you'd have over 10" of insulation in spots, assuming 5.5" columns and standard girts.

How deep will you columns be and are you planning standard or bookshelf girts?

I know one concern with really deep double walls is that the sheathing stays cold and condensation can freeze on the back side of the sheathing. I don't think that's typically a concern in Ohio but something to think about.

I haven't made a solid decision on that yet, probably 12" total from inside to outside.

Standard girts.

Yep, sheathing needs to be insulated on the outside if high r value is used on wall.

Need to do more research and rough in a cost benefit on this. The blown in alone will save $600 over roll insulation. Just a germ of an idea at this point.

I'm thinking radiant heating. My brothers 40x60x16 2x6 framed shop was built with it, was too bad to design and install ourselves. Did everything but the masonry and roofing ourselves.

 

[Firebrick43]

That is certainly not what the manufacturer stated. But now that you said that and I looked closer at the docs provided with it, they are claiming R6 "if" it is used in a certain fashion. I.E. not installing it directly against the metal and leaving an air gap of a certain amount.

Either way, I was really just using it to keep the building from sweating. In that it worked great.

I dont know about Western Washington, but OH is a heating climate. In heating climates you want the vapor barrier on the inside. In cooling climates the outside. Installing a vapor barrier on both is a huge no no as it will trap moisture in the wall and you will end up with saturated insulation and damaged/rotted wood and or mold.

 

[NitroGarage]

Another concern of mine is making sure I don't turn this double wall into the worlds greatest rodent condo, any suggestions on anti-rodent sheathing? I know OSB doesn't stop them, my shed may as well be made of cheese.

 

[Voi]

Another concern of mine is making sure I don't turn this double wall into the worlds greatest rodent condo, any suggestions on anti-rodent sheathing? I know OSB doesn't stop them, my shed may as well be made of cheese.

Not sure but you might as well price metal SIPs while you're at it. Whether as the stand alone structure or as the structural element of a post frame build.

There is a metal SIP manufacturer in Ohio. I'll see if I can find them. I think they mostly make cold storage buildings but do some house work as well.

Believe it or not, some people do combine SIPs with double wall construction.

Back to double wall, one problem people always comment on is how to detail the windows. I think one advantage for a shop build is you could skip them for the most part and get your natural light from glass or partly glass overhead doors.

 

[NUTTSGT]

Another concern of mine is making sure I don't turn this double wall into the worlds greatest rodent condo, any suggestions on anti-rodent sheathing? I know OSB doesn't stop them, my shed may as well be made of cheese.

I believe that is one nice thing about using stick built construction and having a block foundation or concrete stem wall. I think you eliminate the places where they can enter.



If I build a new shop, in the future if things work out correctly, it'll be stick built with 2x6 walls with R19. The bottom 2 inches of the wall at the sill will be spray foamed to help prevent air leaks. I will also put 2x4s horizontally on the outside with rigid foil between them, use Tyvek and cover the outside with ribbed metal. The rigid foam should yield R7-8 and with the R19 a nice R26-27.

 

[86turbodsl]

Keep in mind, the ceiling does about 80% of the insulating value of the building structure, the walls are much less important. Putting 12" thick walls full of insulation seems a bit excessive unless you're planning on 2' or more in the attic. Any particular reason you want this tight a building?

ROI for additional insulation goes down once you get above a certain level. It's not linear.

 

[rerod]

Iv been reading about advanced framing, Double wall and Larsen Trusses. This might become the norm as energy prices continue to rise. But I wouldn't use the concept on a pole barn but on a foundation IMO.

http://www.greenbuildingadvisor.com/blogs/dept/musings/all-about-larsen-trusses

http://www.greenhomebuilding.com/articles/larsentruss.htm

 

[ard]

Iv been reading about advanced framing, Double wall and Larsen Trusses. This might become the norm as energy prices continue to rise. But I wouldn't use the concept on a pole barn but on a foundation IMO.

http://www.greenbuildingadvisor.com/blogs/dept/musings/all-about-larsen-trusses

http://www.greenhomebuilding.com/articles/larsentruss.htm

Agree...there are some really cool advanced framing/wall/insulation methods around.

HOWEVER, it is critical that folks recognize the devil is in the details- screw up moisture control, air leaks, pathways for water or insects or rodents, and you might just build a disaster...

Having a nice fat cavity in a double wall pole barn is great, but there is a lot more to it than that.

 

[stm317]

Insulation is great, but it's easy to go WAY overboard for something that is just a shop or storage area. If you're living in it, and want it to stay 70+ degrees all the time that's one thing but it's pretty easy to use fairly standard insulation techniques and keep an out building warm enough to be comfortable when you're working without spending a fortune on superinsulated walls or the very latest in energy saving green building techniques. If you have the budget for it, and want to do it that's great but for an average GJ user your plan seems like expensive overkill.

Getting some 1.5 inch thick foam boards to run between your posts and the metal (cut to fit between the girts) should give you around R7. That would leave 5.5 inches of wall thickness if you framed out even with the inside of the posts, and you can fill that with whatever standard insulation you want and you'll probably end up with a total R value of R26-R30 without giving up any floor space inside of your building.

 

[lakeroadster]

... But I wouldn't use the concept on a pole barn but on a foundation....

Depends on the style of Pole Building.

The design of a "poles in the ground" pole building is based on a floating slab that can move independent of the poles.

If you build a wall that sits on the slab that is attached to the buildings wooden structure this could lead to structural issues.

Now if you build a pole building with walls that attach to a mono-slab foundation.. then you should have no problems.

 

[kbs2244]

Loose fill will compress and settle from its own weight.
It will settle even when spread across an attic floor.
Use paper faced fiberglass in the walls.
(Un-faced will settle also.)