new here with lots of questions about insulating pole barn.

[way up north]

Hi Guys. Im new here and have some questions for the people that have done this already.
I have built a "barn" on my property...Its my first time doing something like this. Im sure I made a lot of mistakes, and would do many things differently if I were to do it again.
That said this is what I have,  so I'm going to make it work.

I am up in AK with limited access to everything.  I got everything you see starting from clearing the land done in 30 days by myself. Obviously its not done yet but I got it to the point I don't think it will fall over before I get back next year.


I am building this in sketchup as well to help me visualize how to do things I am unfamiliar with. That helps me out quite a bit.


So I have some questions Im hoping you guys can help me with.

I will be converting the right side into a insulated living space. I have a rough idea of how to do this to but I wanted to get some informed opinions on the best way to go about it.

I have a lot of questions  about other issues but I figure Ill start here and hopefully you guys can help me whittle them down.

I will be putting up board and batten on the whole thing eventually so I assume I have to girt everything including the living space. Please feel free to correct me if Im wrong there.
That leaves me with insulation and sheathing questions.


So firstly. Insulation. (In the living area only)

My plan was to put 1.5" pink foam between the girts, then frame in between the posts  so I could put  24" paper backed fiberglass insulation like in this video.

https://www.youtube.com/watch?v=F2Nhshr5CQE

Then I would sheath the living area with 3/8 or 1/2 ply  and cover it in tar paper. Kinda like this video
https://www.youtube.com/watch?v=Ud0M9UZRerA

Over that would be 1/4" thick horizontal strips of ( hoping you guys can help me out here) something that the board and batten would be attached to.

Ok so what do you guys think? is this a good way to go about these first steps or do you guys have a better way?


Thanks very much!

[way up north]

I made have made that first post a bit too complex.
hopefully this helps.

Does this look like the best approach to insulate and board and batten this thing? 
Thankyou, and happy new year.

 

[curved-wood]

You should use a more precise title or split you questions if you want more answers. I prefer to use a continuous vapor poly 6mm than paper back insulation. Instead of tar paper use an air barrier like Tyvek How you are going to insulate the floor ? Are the overhangs takes in account the snow loads ?

[Sedgehammer]

I made have made that first post a bit too complex.
hopefully this helps.

Does this look like the best approach to insulate and board and batten this thing?
Thankyou, and happy new year.

Why 2 sets of girts and the plywood? 

[Andries]

First off: that is one beautiful building. 
Nicely done!
I'm with curved wood on the recommendation of the materials. You're in AK, and there might not be a big box store just down the street, but wherever you do get your supplies should carry the more modern building materials. 
Sedge hammer asks a good question. Your timberframe is well braced, so the plywood and 2x grits are probably overkill.

Heat loss is greatest in the roof, then walls, then floor/slab. Most places in AK have an extreme temp. range, so your choices are: to pay up front for lots of R value and less $ over time for heat, or vice versa.

For walls, go with the foam panels, then stick frame 2x6s between bents and fill with fiberglass. Vapor barrier 6mil plastic on the inside, then finish with whatever suits. 
For the floor, sheet the bottom of the joists with the same foam panels, put thin plwood below that for support and to block varmints. Then fill the joist cavity with blow-in cellulose fiber. Vapor barrier plastc at 6mill the top of the joist and cover with plywood or sawn sub-floor. If the floor joists are 2x8 or 2x10, you'll have R 28 or 36 in the floor. 
The ceiling is where you want the highest R value. Do you want a flat ceiling or a sloped/cathedral ceiling? That answer affects how you'll insulate it.
You're in the high latitudes, so add as much glass as you can afford, and that the windows are rated triple panel with low "E" values. Sunlight staves off the mid-winter blues! 😂
The downside is that you'll be hiding a lot of your skills at timberframing,  but you'll have a snug and efficient building to make up for it.

[way up north]

You should use a more precise title or split you questions if you want more answers. I prefer to use a continuous vapor poly 6mm than paper back insulation. Instead of tar paper use an air barrier like Tyvek How you are going to insulate the floor ? Are the overhangs takes in account the snow loads ?

Thankyou for the response and the Tip on titling my post and breaking them up. I will attempt to organize my posts a bit better.
So I understand poly is used almost everywhere instead of paper backed insulation. However after talking to the neighbors and lot of research I have come to the conclusion the the buildings here in SE AK need to breath a lot more than in a drier climate. It rains here most every day, and mold is my number one concern. The problem with poly is condensation can form behind it soaking the insulation and causing mold problems.
I can't seem to get a consensus from the neighbors on anything lol. there does not seem to be a "right way " to do things here, so Im left do figure out things myself which Is why I come to you folks hoping to get more info. spend less money, and make fewer mistakes.
I am debating tyvek vs tar paper on the outside. I am leaning toward tarpaper because it holds then releases water and breathes even better when wet. Folks up here seem to like it. but again, not all of themlol
I could go either way on this . tyvek would be easier for sure.
For the floor I was going to put in a layer or two of foam boards.
the roof is another big question I want to ask about. I have a plan, but ill ask that later.
I ran out of time to finish the overhangs, before I had to go back to work.lol
Ill be cutting them back to 3' I think that should be fine. I can add some bracing if needed. Snow load here is not bad, but the rain....lets just say ill never run out of waterlol
thanks again for the help.

[way up north]

I made have made that first post a bit too complex.
hopefully this helps.

Does this look like the best approach to insulate and board and batten this thing?
Thankyou, and happy new year.

Why 2 sets of girts and the plywood?

Hi, this is a good question, and something Im debating.
I would prefer not to have to add the pink foam but the whole building is getting girts for the board and batten. so I need to fill in that space between them.
So I have 30 days when I go up this year to get this thing dried in. Im thinking plywood sheathing will go up quick over the girts, and I can come next year and do the BB on the whole thing then. No way Im going to be able to get it done this trip. so the ply and house wrap will have to last the year till I get back. Hope that makes sense.
the second set of girts is just 1/4" material to space the BB off the tyvek or tar paper  so it can breath. I haven't figured out what material Im going to use for this spacer. Something treated or perhaps hardi board? not sure.

If you can think of a better approach( Im hoping there is one) Im all ears.
Thankyou

[btulloh]

Looks like a classic wrap and strap approach to B&B.  Tried and true.  Nothing wrong with that.

[way up north]

First off: that is one beautiful building.
Nicely done!
I'm with curved wood on the recommendation of the materials. You're in AK, and there might not be a big box store just down the street, but wherever you do get your supplies should carry the more modern building materials.
Sedge hammer asks a good question. Your timberframe is well braced, so the plywood and 2x grits are probably overkill.

Heat loss is greatest in the roof, then walls, then floor/slab. Most places in AK have an extreme temp. range, so your choices are: to pay up front for lots of R value and less $ over time for heat, or vice versa.

For walls, go with the foam panels, then stick frame 2x6s between bents and fill with fiberglass. Vapor barrier 6mil plastic on the inside, then finish with whatever suits.
For the floor, sheet the bottom of the joists with the same foam panels, put thin plwood below that for support and to block varmints. Then fill the joist cavity with blow-in cellulose fiber. Vapor barrier plastc at 6mill the top of the joist and cover with plywood or sawn sub-floor. If the floor joists are 2x8 or 2x10, you'll have R 28 or 36 in the floor.
The ceiling is where you want the highest R value. Do you want a flat ceiling or a sloped/cathedral ceiling? That answer affects how you'll insulate it.
You're in the high latitudes, so add as much glass as you can afford, and that the windows are rated triple panel with low "E" values. Sunlight staves off the mid-winter blues! 😂
The downside is that you'll be hiding a lot of your skills at timberframing,  but you'll have a snug and efficient building to make up for it.

Thanks for the compliment! Gives me hope I didn't jack it up too bad.lol

I can get the poly and the tyvek no problem. I understand its code most everywhere. As I posted above I am still undecided and looking for consensus on the tyvek and poly before I commit. I have a theory about what Im gonna do but I always feel better bouncing it off people that have done it before me.  
Mold is my nemesis up there and there are several reports that poly is a bad idea because it doesn't breath at all as well as condensation building up behind it. That said I'm undecided on that, so thanks for the advice there.

Im glad to hear you agree with  the foam panels/ stick frame/ insulation  in the walls. That really seems my only option at this point. 

Your advice on the floor insulation sounds very good. I think I will do that just as you described. Thankyou for that!

Also on the window.. thank you sounds good.

The ceiling........ This is where I wish I had known more before I started. 

We will be doing a cathedral type, and basically the same as you described to floor insulation only using roll insulation instead of blown in. Do you think that will work?
Im limited in options since to roof is on. It is just skip sheathed with 2x6 every foot and tar paper on top of that, then metal. If I could do that again I would have put down plywood over the skip sheathing.
But this is where Im at so Im hoping it will act like a cold roof with air coming under the skip sheathing keeping things cool and dry.

Worst case Ill pull the metal and do it over but I'm hoping I won't have to.

I agree Its a shame to cover it up. I may change my mind and do just the living area.

Thanks agin for the help and compliments from Manitoba.

[way up north]

Looks like a classic wrap and strap approach to B&B.  Tried and true.  Nothing wrong with that.

Thankyou btulloh!

[Don P]

I would attach a 4x4 to the bottom of the sill, foam and tape continuously over the outside of the girts (less infiltration and removes thermal break). You can also foam between girts. 2x sleepers over the girts thru the foam and then siding, fewer fasteners are then penetrating the foam. At the girt level incorporate some diagonal bracing to replace the bracing of the plywood layer. It does not look all that well braced to me at this point. Fiberglass your wall inside, unfaced, no poly. The foam is a vapor retarder, which means the assembly needs to dry to the inside. You do not want a double vapor retarder or any vapor in the wall becomes trapped. If there is enough foam the vapor will not condense on its backside. If there is not enough at least the condensation is outside of the structural elements. While you have time it would be a good idea to read at buildingscience.com

[Andries]

DonP,  with all due respect to your experience and knowledge, which is far better than my meager skill set, here's a quote from an article at buildingscience.com :
"  The vapor drive when it is 40 degrees below zero1 outside is formidable. This is one climate that needs a real vapor barrier, not a vapor retarder. "

[Andries]

The article can be found at: https://www.buildingscience.com/documents/insights/bsi-031-building-in-extreme-cold 
In hindsight, my "Alaska" advice was given based on where I live. There are two seasons up here, this winter and last winter.  ;) I've worked at Prudhoe and Deadhorse and that was in my mind when giving advice.

But, and there's always a but, the OP is in S E Alaska. Which is probably more like Vancouver, where the big battle is against water and mould. Don, your last sentence of advise to the OP is bang on. 
Run a search for articles based on your climatic type and there you are; the best available knowledge. 

[Don P]

Definitely get advise for there. What prompted my post was the decision to put the vapor retarder, the foam, on the outside, then suggestions to place another vapor retarder, poly, on the interior. That is a mold recipe in any climate.

Heat always moves from hot to cold. The moisture always moves along with it, that is basically the definition of vapor drive. The vapor in the wall assembly is looked at on a full year cycle. If the moisture that is driven into the wall assembly in the winter cannot at least dry back out in the summer it is going to get wetter and wetter.

With all due respect to Joe's expertise, I've never seen a real vapor barrier in the working world, that simply doesn't happen. There must be a drying direction. Once you choose the surface you are retarding, the assembly must dry to the other surface. You cannot keep moisture out of the cavity, you can only pick which side is the drying side. That doesn't mean you can't choose the wrong surface or wrong materials. 

[way up north]

Thankyou Gentlemen for commenting. I very much appreciate it.

Don P.,
Thankyou for pointing me in the direction of buildingscience. Ill go over there and consume that info.

Yes you are right it needs much more bracing. Ran out of time and materials. Just got the minimum done to keep it up for a year. 

If I get the general idea of what your saying, the foam on the outside is acting like my vapor barrier, meaning all the vapor produced inside the house, breathing, cooking, heating act. as well as outside moisture that leaks in that goes into the insulation has to somehow dry to the inside.

This is important as this is temporary housing till the monitor house barn is built and perhaps guests to stay in, so no continuous heating with fire to dry out the inside.....

My first though is to lose the girts, lose the foam, and paper backed insulation will then work as it is able to dry to the outside?

Again Ill read the info on the link that you posted but Im trying to see if I understand what your saying about the science of it.


As far as poly goes.

The problem I have with poly on the inside is there's no where for moisture to go. Where does moisture produced inside the house go?

Ill use a fridge or an ice chest as an example. Close up a fridge with the power off and come back a year later and open it.. it won't be pretty. Or  as we did with my rv up there. Close it up tight,  Come back next year to a toxic biohazard.

The following year we left the windows open while we were gone, tried to provide as much ventilation as possible and no mold problem ( not as bad anyway) the rv condensates inside still but it was able to dry due to the airflow from the windows.

Pro tip. don't buy a rv in SE AK....

Thanks again guys, I really appreciate your help. Ill go check out that info now.

[Don P]

Remember the FEMA trailer mess in New Orleans? I think the takeaway is RV's are not much.

While reading there look at his perfect wall, that works in any climate but it is expensive. Going back to what we were talking about above, the greater the temperature differential the stronger the drive, or as the old folks would say, the colder the day the stronger the draft. The greatest number of SIPs failures was in AK. Because they are basically chunks of foam with joints all the way though them, vapor drive caused moisture buildup at those joints. That is where wrap and strap with offset and taped joints performs better. No matter how hard we try, we cannot make perfect joints and connections in the field. Add to that the building moving during seasoning or seasonally and there will be leakage, it has to be able to dry.

 I suspect just fiberglass drying out will work but I live in the southeastern mixed humid climate. The main thing we've learned here is lose the poly, its on the wrong side half the year. Especially if there is AC, the vapor drive is from outside in, trapping moisture on the backside of the plastic. It is better to control airflow through the wall and let it dry to either face as the season dictates the drive direction.

The interior mustiness when you are not there, I think you need to at least passively vent the interior while you are gone, moisture does accumulate and starts to grow things in humid places when the air is not moving. That might be vents low and high and let warmth move the air, or if that isn't working it might be worth looking into some kind of PV driven ventilation.

All this is just my opinion, go to the sources, your state also has information available.

[Andries]

Here are the words to live by in Don's post:
" There must be a drying direction. Once you choose the surface you are retarding, the assembly must dry to the other surface. You cannot keep moisture out of the cavity, you can only pick which side is the drying side. "

[Andries]

Up North; a big part of your design challenge is that you are using the building seasonally. 
The use of an active air exchange ventilation unit (HRV) on a year round basis may be the long term answer. If you aren't on the power grid, even a modest solar panel can power an air to air exchange fan.

At this point, you can choose the best recommended insulation and ventilation system for your climate. You can then apply that choice to floor, walls and ceiling. 

You are in an enviable position to 'get it right'. 

[curved-wood]

I am in cold climate (Québec ) and the more common assembly is in the following order from outside :
siding, 3/4''forenz, air barrier ( not poly ), presswood (I prefer 3/8'' plywood ), batt insulation in 2x6 stick frame, 6 mil poly, sheetrock. In the recent house of my son, we add an horizontal 2x2 between the poly and the sheetrock to run the electricity wires without punching the poly. Air tight is the goal. Any joints of the poly is double caulk with acoustic sealant. Of course an heat exchanger is compulsory. The winters are cold and very dry so that is why the air tightness. The big temperature differential between the inside and the outside pushes the inside humidity outside. The air barrier let the humidity to go out but not let the water to get in, so the wall breathes from the inside out.
But if you are in a climate like Vancouver that is another story. Probably humidity is more a challenge than a super insulation construction especially if you are there only part time