Insulating my pole barn

[RobitussinPR]

Hi All,
Longtime lurker, finally getting my act together and registered on here.
I bought my first house a couple years ago and it came with a 30x30 pole barn. (yahoo!) I'd like to insulate the barn and put in a heat pump for temp regulation and am looking for the most logical/cost effective way to do it.

It has the original wood siding (T1-11 or some equivalent from the 80s,) that was nailed directly to the framing/girts. No sheathing or vapor barrier. The siding is in fair shape, but shows its age and has quite a few gaps/holes from animals, wear and tear, so there are mice/wasp issues in the summer and its frigidly cold in the winter. I live in the mountain west, north central washington, so cold snowy winters and hot dry summers. The options and pros/cons of each I've considered are:

1 - Patch the gaps holes as best I can, put in 2/4 framing and get an inch or so of spray foam put in to create a vapor barrier and tighten things up, then put batts in the framing, then interior siding (thinking plywood to hang stuff and durability.) Maybe the most effective, but seems expensive with the spray foam.

2 -Patch holes, then try and vapor seal the siding as best I can with tyvek or something similar, then frame and batts. I worry putting up vapor seal from the inside is bound to fail, then when moisture/ animals get into the batts I'll lose my insulating value and the whole operation will be for naught.

3 - Put up rigid foam on the inside on the girts, use the canned foam to seal gaps, then interior siding directly on that to the girters. Seems like a lot of work to cut the foam to size, and seal the gaps, and I worry that the direct contact of the foam on the girts and siding may lead to moisture accumulation, though maybe Im smoking dope on that thought.

4 - Put rmax thermasheath on the OUTSIDE, using the current siding as sheathing, then put new siding on top of the rmax. I could still frame the interior and put in batts, or just put siding up. I like the idea of this, seems like possible the most effective option, and I could put a less flammable siding on. Downside is I suspect it may be the most expensive options, sounds like the most effort, and I am not sure how the extra wall thickness would seat into the foundation slab and roof.

I use the garage space for a gym, woodshop and gear/toy storage, so doesn't require intensive temp regulation, but keeping it between 50-75F would be killer for my needs

Additional question Im pondering if you made it this far -
what size heat pump would be good? Was thinking the 23k BTU Mr Cool, but its a big space and I havent had a minisplit system before.
Roof insulation? Was thinking batts and some sort of membrane to hold them up there but open to suggestions.

Best wishes and thanks for helping me work through what has been keeping me awake many nights

 

[steg1]

I built mine in 2011 and had it spray foamed best choice I ever made

 

[Hank11]

Assuming the exterior siding is truly fit to remain in place, I'd install a rain screen over that, a proper rat guard type of flashing at the bottom, and then new siding of your choice. A tight water and wind shell over what you have now. If that is too much work, then new siding over what you have. The outside needs to be water and wind tight.

On the interior you could then install batts or blankets of insulation. You don't give the dimensions of your bents, so depending on that answer you might be able buy big blankets of insulation that fit the spaces.

Another choice would be as above but spray foam the inside and either cover it or leave it exposed per you needs. If you do this do not cover the old siding with new - you might be creating a rot problem if the old siding can't dry to one side. Do the rain screen. If you do anything inside with flames or sparks you can have fire proofing sprayed over the foam or cover the walls.

Most important is the ceiling. Thats the most effective insulation for your dollar.

 

[billconner]

I think use existing siding as sheathing, put up house wrap, put up 2" EPS or XPS as continuous insulation, then new siding. Hard part is finishing around doors and windows but not too hard. You may find this is sufficient but framing either way, R13 (3.5") batts, a vapor barrier, and whatever you want for interior - drywall, ply, OSB, metal, or I'd do rough sawn pine in mine.

While that only adds up to R23, it's considered equal performance to R30 by code.

Over I like ceiling and lots of cellulose but there are options, all with a vapor barrier on inside of insulation.

 

[steg1]

You carpenters are great the ones that do it right. I know I had my barn spray foamed it was three years before any bugs got into that barn just on the side walls Was the Foam used.

 

[mepstein]

I had a t-111 sided workshop. The siding was a mess so I took it all down (it was even worse than I realized) took down all the mouse infested fiberglass insulation and the cheap warped interior fiberboard. Put up osb, tyvek, new siding (vinyl to discourage the woodpeckers, carpenter bees, etc) rock wool (awesome stuff) and a still to be finished interior wall. I would have liked to use metal for the exterior walls but all the falling tree branches would be rough on it.
My suggestion is; don’t skimp on the rehab. Make it nice. You will be glad you did when it’s done.

 

[RobitussinPR]

Great suggestions and insights. Much appreciated! Ill post some photos soon to see if anyone else has thoughts.

Assuming the exterior siding is truly fit to remain in place, I'd install a rain screen over that, a proper rat guard type of flashing at the bottom, and then new siding of your choice. A tight water and wind shell over what you have now. If that is too much work, then new siding over what you have. The outside needs to be water and wind tight.

On the interior you could then install batts or blankets of insulation. You don't give the dimensions of your bents, so depending on that answer you might be able buy big blankets of insulation that fit the spaces.

Another choice would be as above but spray foam the inside and either cover it or leave it exposed per you needs. If you do this do not cover the old siding with new - you might be creating a rot problem if the old siding can't dry to one side. Do the rain screen. If you do anything inside with flames or sparks you can have fire proofing sprayed over the foam or cover the walls.

Most important is the ceiling. Thats the most effective insulation for your dollar.

What wold you recommend for rat guard flashing? Insects are ever present in our house and barn, so Id love to mitigate their precence and damage.

 

[Jakemedic]

My dad always said there are two ways of doing something. The right way and again. He was pretty wise! I try to use that statement whenever I am doing something like what you are doing. Doesn’t leave me wishing I did it another way. Let us know what you decide!

 

[OX1]

I built mine in 2011 and had it spray foamed best choice I ever made

Same year I built mine and I don't see how you keep inner wall from possibly sweating, without at least 1"
of spray foam sealing right up against metal (least in my neck of da woods).

 

[Hank11]

Great suggestions and insights. Much appreciated! Ill post some photos soon to see if anyone else has thoughts.



What wold you recommend for rat guard flashing? Insects are ever present in our house and barn, so Id love to mitigate their precence and damage.

Pictures of your building at the ground level would help get an answer. I'm guessing its a typical pole barn with concrete poured inside? Or something else? Lots of ways it could be. Basically, some metal flashing that covers the slab and wall junction on the outside so no vermin can enter.

 

[RobitussinPR]

Sorry for the delay, work was killing me this week. Got some photos of the exterior and interior walls and ceiling. And one showing how the siding sits about 2.5 in away from the slab. It is concrete slab, with 6x6 posts and 4 2x8s sistered as the cross beam for the trusses. I'd like to put a side door on the right side with an awning coming out 12ft for extra outdoor storage

 

[billconner]

Well, I doubt many of us quite understood the construction. It looks like board siding, not a panel like T 1-11 at all. Am I misreading the photos?

Very interesting and unique - to small garages - roof structure and gable siding.

 

[dfiler2]

That's a great looking building. I'm really not sure how I would do that one but I would want to save the siding, probably a rain barrier on the inside then spray foam if possible. If you can't do the foam then your second and third ideas would both work well.

Looking a little closer how far apart are those rafters?

 

[billconner]

Yeah. I withdraw what I said above. I think what dfiler2 says is a good approach, though I regret you have to cover such interesting construction.

Some sort of metal "Z" flashing under siding and over slab edge would solve that problem.

I might use 15# felt for rain barrier because it's black showing through board gaps. Cutting rigid foam to fit between girts would probably be less expensive than spray foam. Another layer of rigid foam over first and covered with rough sawn would be pretty efficient and easy to do. Overhead is not as easy but I'd try to leave trusses exposed. You could do similar to walls, but spray foam and than batts or loose fill and a really good vapor barrier under finished ceiling - boards or drywall or liner panel.

 

[RobitussinPR]

Those are great points. Do either of you happen to have experience with DIY spray foam? I got a quote from only local insulation company and it was 17k (!) So Im now either thinking patch holes and DIY some foam, or do with felt, then rigid foam, or rockwool batts.

Rafters are 24in so I was thinking fiberglass or rockwool batts up there with some sort of membrane underneath.

 

[steg1]

Wow have prices changed I am in Ohio and I had my 32 x 48 barn just the sidewalls spray foamed. 12 foot walls you might as well just say 2 inches thick and the one wall has got the 12 foot door and a 10 foot door. I had this done approximately 2015 and it was like $3000

 

[Firebrick43]

Well, I doubt many of us quite understood the construction. It looks like board siding, not a panel like T 1-11 at all. Am I misreading the photos?

Very interesting and unique - to small garages - roof structure and gable siding.

No, your seeing it correctly, its very much appears to be car siding. Definitely not T111

 

[RobitussinPR]

You guys are on point, it is indeed car siding, no T111! Thanks for the insights and knowledge sharing. I'm going to try and maintain the current siding and work to seal the interior with some wood patching over bigger holes, then felt paper, then 2x4 framing with DIY spray foam, followed by batts and then plywood interior siding. Ill post some photos as I make my way. Cheers!

 

[Fav Onefour]

Quite the interesting building construction.

I want to clarify @RobitussinPR , how you are planning to do the steps.
Are you talking about putting felt paper on the inside? It sounds like all the work is on the inside with no steps on the exterior.
That water should not get to the framing. If I understand the steps correctly, you would actually be trapping water from the exterior gaps. You already have quite a plan in place. I'd like to clarify the steps to make sure it's a long lasting structure.

 

[Hank11]

I'd cover the outside with black paper and then side it with foam sheets and whatever exterior you want. You can add metal flashing around the bottom when you do this. The inside looks kinda cool and with a ceiling and some insulation in the ceiling you would have a pretty nice building.

 

[RobitussinPR]

Quite the interesting building construction.

I want to clarify @RobitussinPR , how you are planning to do the steps.
Are you talking about putting felt paper on the inside? It sounds like all the work is on the inside with no steps on the exterior.
That water should not get to the framing. If I understand the steps correctly, you would actually be trapping water from the exterior gaps. You already have quite a plan in place. I'd like to clarify the steps to make sure it's a long lasting structure.

Yes, My thinking was to just put the felt between the girts, that way the spray foam wont be on the siding and if the siding ever needs to be replaced or minor repairs I wont be dealing with siding and spray foam stuck together. This would mean that the framing is outside of the vapor barrier. My thinking was that since that is the current situation, the framing would still do ok with moisture drying to the exterior of the building. I'm east of the cascades in the mountain west so quite a dry climate. We get snow but the rest of the year is arid as heck. H

I was initially more inclined to the exterior approach of vapor barrier, then rigid foam then new siding, but Im questioning the need for new siding after taking a closer look at things.

Happy ot hear other thoughts or perspectives, this has been a great opportunity to suss out my thinking!

 

[billconner]

For me, it would come down to how much time I'm going to spend inside it. If a shop I'm in at least 5-10 hours a week, I'd like to preserve the current appearance and put rigid foam and new siding on exterior - though some issues to solve like windows and eaves. (I don't know if I'd be crazy enough to rip off roof and insulate on top of it or not.) If mostly for storage of cars, canoes (I have 3 currently), and such, I'd do what you proposed. (I might think about rigid foam to save money.)

 

[wascallyrabbit]

building a 64x50 post and beam building. plan is closed cell spray foam 3" ceiling 2" walls. know the problems is do sheath the build first to air seal it. not sure the best method for air sealing and keeping pests out. have to figure out how to air seal the tunnels that metal siding creates. sheathing down to the splash planks/ground boards make it fairly easy. rockwool seems interesting along with saga myra as a vapor barrier. spray foam may still come out a bit cheaper. haven't run the number on rockwool but have a quote to do the whole building for 28k.