Insulating a 20x20 carriage barn/shop

[Audi]

So I recently built a 20x20 timber frame carriage barn on our property to serve as a garage & workshop, located in central NH.  Originally I hadn't planned on insulating any of it; so far the roof is boarded and shingled and the rest of the exterior is 1" pine shiplap.  I figured I'd use it like that through the winter, then add clapboards, windows, etc., come spring.

Now that it's enclosed and I've spent some time in it, however, I'm wondering about adding some insulation to the first floor.  I'm not looking to fully insulate the entire thing to r-49 in the ceiling, r-25 in the walls and heat it year round, but I was thinking about using 2" foam panels cut to infill the spaces between the first floor posts & braces, covered with 1/2" sheetrock, and applying the same foam panels on top of the second floor deck.  It would only be about an r-9, but I'm not out there all the time and would just want to help the first floor retain heat a bit better while a heater's on while I'm out there.

My main question is regarding a vapor barrier - the ceiling would be easy enough, but I'm wondering about the walls.  As I'm only looking at a lightly insulated outbuilding, do I even really need to bother with a vapor barrier for the walls, and if it is necessary, how would I go about it?

Thanks,
Audi

[beenthere]

Welcome to the Forum.
The vapor barrier is to stop moisture moving from a heated space out to a cold wall and condensing on that cold surface.
So much will depend on your usage during the time you are in it, how you are heating it, and how much moisture you are creating. In homes, showers, baths, cooking, drying clothes, drying firewood, etc. all create moisture as well as just breathing out. The moisture will condense when it comes in contact with the colder surface which also depends on the outside temp's. Your occasional use likely won't make for much condensation.

Your call if a vapor barrier is needed. Placing a plastic vapor barrier just under the drywall would be my suggestion if you do.

[mikerat]

Rooster is building a carriage house for a customer and is adding the foam panels to the outside like a homemade sip, it was very cool and looked very doable. I'm sure Rooster will see this and it's better if he explained the process.

Mike

[Rooster]

Thanks Mike!

Yes, it's true.  The frame that I am currently working on, is made out of reclaimed beams from a barn that I took down.  In fact, the second story floor is made from reclaimed 3x8 DF joists and 1 3/4" tongue and groove flooring from a couple of threshing floors.  I am covering the outside of the frame in mutiple layers. First is 3/4" reclaimed barn siding with the painted side out, so that the deep patina of the wood is seen from the inside.  I will then cover the walls with 15# felt/ tar-paper to be used as a type of vapor barrier and wind barrier...  then 2 layers of 1.5" foam insulation with staggered and taped seams. I am using full rough sawn 1x4 for my strapping which will be secured with 80d ringshank nails to all the interior siding nailers/girts, rim/outside joists, endwall tie-beams, endwall rafters, pretty much any where the first layer of siding is attached to the frame.  The final layer is new commercially made rough sawn S3S Pine/Spruce 1x12 barn siding that will get primed and painted.   The roof will also be "Wrap and Strap" with corrigated steel roofing.

So, my suggestion would be to remove the siding from one wall, hang drywall on the outside, felt, foam, strap, and then re-install your wood siding.  Then move onto the next wall... or do two walls at the same time.  My thought is that you need to close up each wall quickly, so that the drywall in not exposed to too much weather, so by doing it a section at a time,  it might work out best for you.

The other idea is to fill the cavities between the second floor joist with cellulose insulation.

Your idea of insulating on the inside and then adding drywall would work...but then you are covering up all of your frame.  You could have stick built the workshop if you were just going to cover in the interior walls...so, I am encouraging you to show off your frame. ;)

Sorry guys, no pics until I'm done with the project.

Rooster

[Audi]

I appreciate the replies, guys, and that barn that you're building sounds like a cool project, Rooster.

The method you're using is exactly what I would have done had I wanted to insulate the whole thing, but unfortunately I don't have the budget to do that on this project...to wrap & strap on the outside, I'd have to go all the way up my gable ends, and I really don't need (or want to pay for) the whole upstairs to be insulated (it's just storage, and with a 16-pitch, there would be a considerable amount to insulate).

No worries about covering up the frame, as I'm just considering 2" foam cut to fit the recesses between posts and braces, etc.  All braces and posts will be proud of the sheetrock.  If anything, had I thought about insulating this way from the get-go, I would've moved the braces 2 1/2" in from the outside wall plane.

As beenthere put it, it's a bit of a judgement call...I think I'll be OK doing it the way I'm thinking, using faced foam (foil towards the drywall).  I'm just looking to cozy up the first floor of my shop on the cheap, and r-values I'd end up with aren't too far off what they had using a plaster/lath wall with no insulation, never mind vapor barrier, way back in the day, and plenty of those buildings haven't rotted out due to moisture condensation.

Thanks again,
Audi

[Rooster]

Audi,

If you insulated the outside, could you build a stud system up at the gables to take up the space of the foam insulation and then put firring strips for your clapboard?

Even if we both had identical buildings to insulate, and if you had skills and knew what you were doing, and did it your way  ;), and I didn't and did it the way I suggested (minus removing the shiplap since you did mention wanting to use clpboard.):D, and we want to see who would finish first,  I think I still might have a slight lead.

Not that faster is better, but I would rather custom cut studs to fit the gable, than custom cut foam to fit inside the opening of the frame.

The nice thing about this forum, is that it allows the free flow of ideas...which we all can take or leave.

I hope this helps.

Rooster

[frwinks]

As beenthere put it, it's a bit of a judgement call...I think I'll be OK doing it the way I'm thinking, using faced foam (foil towards the drywall). 

The PERSIST/REMOTE wall system suggested by Rooster is a great performer. 
Good choice on the foam.  Properly detailed it will create a great air barrier, which is half the battle in vapour management.   The other half is using foam thick enough to move the dew point to inside the foam.  If it's polyiso foam you're using, it'll do the trick ;)

[Thehardway]

Audi,

At the risk of being non-traditional and sounding like a broken record, the fastest, cheapest and best performing system for your building would be a very thin coating of spray in place foam.  I would go about it in the following manner.

Install a membrane (could be anything that spray foam will stick to, craft paper, to Tyvek, consult your local foam applicator) and then nail some horizontal members between the posts on 2' centers.  The pupose of the membrane is to keep the foam from sticking to the back of your shiplap which allows for ease of replacing boards in the future without effecting the integrity of your insulation.

Once this is in place, spray 1-1.5" of foam in between the horizontal members and right up to the posts/braces.  If well applied the foam will seal out all possible air infiltration and prevent air and moisture movement  through the walls making it very easy to quickly bring your building up to temperature with a small heater or woodstove.  You will get more performance value out of the spray foam than you would fully insulating the walls with r-19 fiberglass batts, packed cellulose or strap and wrap rigid foam as all of these still allow air and moisture infiltration.  You can cover up the foam by nailing sheetrock or plyboard to the horizontal members, personally I would use pegboard.  It will act as an acoustic baffle and make things nice and quiet as well as give you a great way to organize tools etc.

This is called flash foaming and it is a proven method for sealing up a building. Do the same for the ceiling.
Don't worry about the calculated R-value. It will mislead you.  Make sure you have a window you can open as it will likely get too hot if you don't watch your fire closely,
This method, all installed will cost just slightly more than the rigid foam board you would purchase yourself and still have to cut and fit and when you start to look at the waste, it will likely be cheaper.  The spray foam will all be installed in a 3-4 hr. period and be a complete seal.  The rigid foam board would still leave you with gaps, cracks, and drafts.

You may wish to spray it yourself using a product like "Foam it Green".

Spray in polyurethane foam will not hold water, will not rot, mold, mildew or provide any nutrient for insects or vermin.  It forms its own vapor barrier and will not loose its insulative properties over time.  It will not sag or fall or become compressed.  All factors to consider when choosing an insulation.

The spray foam will also keep things cool in the summer for you.

[barbender]

I've been fitting 2" expanded polystyrene in between floor joists on my rim joist to seal it up (stick framed). Anyhow, I bought a Great Stuff Pro gun dispenser for expanding foam, it works way better than the regular cans, you can control the flow rate and actually do some precision work. This method would work good on your timber frame, you get a good air seal and its way cheaper than spray foam.

[Audi]

Thanks for the replies, guys.

I like that idea, Rooster; I may end up doing something like that around the outside.

Good thoughts on the spray foam as well - I've never used it before and hadn't even considered it.

At this point I'm just researching some ideas and looking for new ones, and as I won't get the windows in until the spring, I'll probably wait until then before moving ahead with any insulation.  It'll be a chilly winter in there, but in my line of work I don't have much extra $ until the warmer weather's here.

Thanks!
Audi

[Rooster]

Hey there,

This post is in respond to some ideas that I had previously mentioned to Audi about his project.


 
This carraige house is 28ft x 28ft with a 12ft x 28ft porch addition made out of reclaimed barn materials. With new pole rafters and new ship-lap pine roof decking.

  

  
I covered the frame with a layer of reclaimed barn board siding, and then wrapped it in 15# felt paper.

  
I added extensions to the rough opening for the doors and windows so that I could add the foam insulation and still have a nailing surface for my siding/ window flange.

  
Here is a view of the inside wall surface...this wrap and strap system allows for a fully exposed interior frame.

  
All of the electrical is attached to the outside of the first layer of siding, and will be enveloped within the foam layers.

  
I used 2 layers of 1.5" foam on the outer walls and taped the seams. The straps are made of full 1x4 reclaimed pine barn decking, and were secured to the nailers, horizontal beams and posts of the timber-frame with 80d ringshank pole-barn nails.

  
The siding was pre-primed with oil based stain and nailed to the straps using 10d galv. spiral deck nails.

  

  

  
I used 5 in. of EPS foam on the roof consisting of 2 layers of 2in. and 1 layer of 1in. When I started laying down the roof insulation, I planned the stagger so that the first foam board is 4'x8', the second is 3'x7', and the third is 2'x6'. 

  
The strapping for the roof was made from 2x6 barn rafters ripped in half. (1.75"x 2.75")  I used 1/4"x10" Assy wood screws that secured the strapping to the pole rafter, sandwiching the foam layers in between.


 
The strapping extended out past the endwall/gable to form the overhang. A nominal 2x4 was used as the rake, and was wrapped in white steel trim for low maintenance.

  

  
The porch is open to the elements so the roof above that section did not need insulation, so in order to keep the roof line the same, 5in tall rafters were placed on top of the decking to take up the space of the insulation.

 
The roofing material is regular pole-barn steel and was screwed to the strapping.

Peace,
Rooster


 

[beenthere]

Thanks for the detail
You should be able to heat that one end with a candle.

[jueston]

thanks for all the pics, it looks like some awesome work

[Jim_Rogers]

bump to the top of the list

[den]

Audi
I would like to see pics of your carriage garage.
I have a thing for carriage garages, I'm thinking of building one.
I have plans from Eli Townsend & Son, Deep River, CT
http://www.thecarriageshed.com/shed.htm
Timber framing sounds interesting.

[Brad_bb]

Rooster,
At the base of your walls, it looks like you have 2 two by fours nailed together.   Are they just screwed to posts?  Do they touch the concrete floor at all?  One thing I worry about is Carpenter ants or termites.  Are you using any flashing at the bottom to prevent their access?

[Rooster]

Brad,

The treated 2x4s are screwed to the outside of the concrete foundation, flush with the top of the foundation wall and below the sill.  I did not use any flashing, but it could easily be added to help prevent insects from getting into the wall.  The property owner will probably be adding this building to the "bug guy's" list of things to spray for the spring and fall seasons.  Asia beetles and Boxelder bugs are everywhere in the fall once the bean fields are harvested!!! 

Rooster

[Piston]

Rooster,
Thanks for posting those great pics of the wrap and strap process.  It helped me understand it a lot better! 

Audi,
Where in Central NH are you located in relation to Alton?  I have some land up there that I hope to someday have a timber frame on.  I do a lot of boating/fishing on Winni. 

I'd love to see a pic of your project. 

-Matt

[Brad_bb]

One more question,
When you are installing the siding, are you leaving a gap between boards for expansion? How much?
It appears like you have two nails on each side of the siding board.  Does this creat any problem for expansion? 
Lastly, Are you going to cover the seams of the siding boards with a smaller board (batten)?
Thank you,
These two recent threads on wrap-N-Strap are good stuff!

[Rooster]

Yes,  I will be using a 2 1/8" wide batten to cover the seams.

I also just nail the outer edge of the siding at the sill, girts, and top-plate...this way the batten will cover the siding nails and there is less chance of water getting throught siding at the nail-holes...plus, it makes for a cleaner looking surface for the siding. 

To gap or not to gap...
That depends on the type of siding...species, cut green, KD, re-claimed, etc.
The outer layer of siding that I normally use is commercially produced EWP 1x12, which is actually 13/16"x 11 5/8"  S3S and rough on the outside.  If I feel that the siding still feels "wet" I will leave no gap...if it's winter time and the siding feels dry then I will leave a slight gap. If it's green cut, no gap, and I might even just sticker the siding awhile longer if I can leave the frame exposed. 

A lot of veriables to have set rules..imo

Rooster

[Brad_bb]

So the nail on either side of the board...on a green board does it then start to split the board at one of the nails as it dries... or on a dry board, does it buckle the board in the middle if it absorbs moisture?

Maybe this is not a problem for a soft wood, the EWP.  I wonder if it would be more of a problem for Spruce, or a hardwood?  Traditonally how were they nailed?  If only one nail in the center, that would eliminate the potential problems I mentioned.  Or does this not happen?  I want to understand the best practice for the board and batten siding.

[Jim_Rogers]

There are probably as many ways to nail on board and batten siding as there are carpenters doing it.

I was told that normally you do nail it in the middle to allow the edges to expand and contract under the batten. And that the batten nail went in between the boards.

Another told me to nail one side of the board and let that side's batten cover that nail and let the other side's batten hold it on. And it would expand and contract on that second side, under that batten.

Personally I think of board and batten as kind of a temporary siding method until you can afford to improve the siding by adding something more. Like clapboards or shingles.

I have a customer who has batten on his garage and every couple of years he's back here getting more batten stock as the battens on the sun side of his building dry up and don't work for him. He is replacing them regularly.

I like ship lap much better.

But these are just my opinions.

Jim Rogers

[beenthere]

I've had board and batten siding (most of it still original) for 44 years. Don't view it as anything 'temporary'.   Only replacement was when putting in new windows that required some different lengths, so put on new boards.

Put two screws at 2" apart in center of 12" board, and one longer screw in the center of the batten. This is all Western cedar rough one side. Originally used aluminum nails, but they work loose whereas screws do not.

Results using other species will likely vary. ;)