Best Insulation for Old Farmhouse
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philupthegastankUser is Offline
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16 Dec 2014 11:42 AM
Hi there, I just gutted my property in the northern midwest, (zone 7). its an early 1900s 2 story balloon framed farm house. I only ripped off the plaster because most of it was falling off and wasnt worth the effort, plus we are putting in all new electric, ducts to the 2nd floor and installing a 2nd floor bathroom, so with all that work, just figured itd be the easier thing to do. Anyway, the house is down to the studds and lath (ill be ripping otu the rest of the lath soon) and i was wondering what the best insulation would be to make the house more energy efficient. Ill be upgrading to a propane furnace and also putting in a wood stove. After all the lath is off I will be caulking like crazy, but then after that will be putting in new insulation. after researching ive read that either open core spray in foam insulation for each exterior wall cavity, or only doing 2" of foam then followed by unfaced batts. I have a lot of uneven cavities, so doing batts is going to be a head ache. Also the first floor has tar paper on around the house, but then on the exterior side of the stud cavity, there is old blow in insulation. should i rip out all the old tar paper along with the old insulation? Any advice appreciated. javascript:amaf_insertHTML('');amaf_toggleInline(5009,29130,0);
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16 Dec 2014 12:15 PM
Consider low temp heat pumps (vs a propane furnace), wet sprayed cellulose and taped rigid foam on the interior side.
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16 Dec 2014 02:25 PM
Is the siding is nailed directly to the studs, without any plank sheathing under the siding?

What is the material stackup, from the exterior side paint to the stud edges?

If open cell foam can work with your exterior-side stackup, it would air seal well, but would still need an interior side vapor retarder. Certainteed MemBrain or Intello Plus would be better than 6 mil poly). From a thermal performance point of view 2" of closed cell foam + 2" of fiber insulation would be about the same, but would cost more than 4" of open cell foam. From a moisture control point of view the closed cell foam would inhibit the drying of the sheathing a bit, but would also limit the wintertime moisture adsorption into the sheathing somewhat more than MemBrain would.

Wet-sprayed cellulose would have comparable thermal performance to open cell foam, and would be more protective of the wood, since it would buffer and share the moisture burden. It could be more problematic than a foam solution if there is no window flashing though, since it would hang onto bulk water incursions for longer. If the windows are properly flashed it would be a great way to go.

In most locations heating with cold-weather ductless (or mini-ducted) heat pumps is cheaper than heating with propane. What are your electricity rates and propane prices like?

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16 Dec 2014 03:53 PM
There is plank sheathing under the siding. My electricity rate is $.114 per kWh and propane is around $1.80 per gallon. I have yet to come across someone suggesting those heat pumps, would that be sufficient for a 2 story 2,400 sq ft house or would you have multiple systems?

And have you ever heard of this:

"Because of where you live in the cold Northeast - I'm just above you in NH - it would be a GRAVE mistake to add insulation in the wall cavity.
The reason your house is still standing with no wood rot is simple. The balloon framing used in houses of that period - I lived in one back in Cincinnati, OH in the 1970's and 80's - allows water vapor that passes through the plaster and lath to be vented up into the attic of your home.
Once up there, it usually was able to dissipate out gable vents or through the roofing. Many older homes had roofing material and roof sheathing that would allow lots of air to pass through them, but not rain water back into the attic.
Balloon construction was probably invented to do this job as houses built without this open passageway probably developed rot in short time as the water vapor in the winter time would condense in the cavity and be unable to EVAPORATE quickly.
Read this column I just posted about Vapor Barriers vs House Wraps to give you more background.
If there was a way for you to install a vapor barrier to STOP the water vapor from getting into the wall cavity, then I'd say move ahead with the insulation. But I don't know of any TRUE paint-on or spray on vapor barrier that would provide enough of a seal."

I have heard from other old house owners that they do not insulate, only the attic, and then they caulk and spray foam like crazy around windows, doors, ect.
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17 Dec 2014 01:31 PM
Is there tar-paper or some other sheet layer between the siding and planks?  If yes, what?

Clapboards, or something else for siding?

How deep are the roof overhangs?

Is there window flashing?

The prescription to not insulate is a bad one.  Water vapor diffusion from the interior can be controlled adequately for any climate, by correct layering and materials used in the wall assembly stackup. As long as there is at least some ability to dry toward the exterior via vapor diffusion, and bulk water incursions from the exterior are limited it's possible to do this in a very moisture resilient way. It's true that insulating WITHOUT the right stackup can be risky (as in just blowing in some fiberglass can crossing your fingers), but since you're doing a full-gut rehab on the exterior shell, you have the opportunity to do it in such a way as to maintain moisture resilience.  Air-sealing-only makes sense in some situations, say, if the siding is clapboards nailed directly to the studs, but even that is addressable in a full-gut rebuild from the interior.

It's almost impossible to adequately air-seal plank sheathing with caulk, but it's possible to get there with housewrap on the interior side, which is cheaper than air-sealing with foam.  In a US climate zone 7 location if you use closed cell foam to air seal the planking it needs to be sufficiently thick that the R-value of the foam is at least half the total center-cavity R-value.  If those are full-dimension 2x4s that means 1.5" of closed cell foam is not enough, but 2" is.   But it has to be closed cell, not open cell, so that the vapor-retardency of the foam is sufficient to protect the sheathing from interior moisture drives in winter, leaving the interior side sufficiently vapor open that the cavity can still dry.

But 2" of cc foam will run over $2 per square foot, whereas 4" of open cell foam (a full cavity fill) costs about $1.50.  Performance wise the 2" foam + 2" fiber isn't much better than a 4" open cell solution.  Open cell foam also air-seals slightly better than closed cell, though both are pretty tight.

To protect the sheathing from winter moisture drives means you need a "smart" vapor retarder, which is vapor open when the air next to it is fairly humid (as happens in spring, when the sheathing warms up and releases some of it's moisture accumulation) but is fairly vapor tight when the air next to the vapor retarder is fairly dry (which happens in winter when the sheathing is adsorbing moisture from the entrained air in the cavity insulation). Certainteed MemBrain is cheaper than the difference the cost of the foam.

If you can tolerate the loss of floor area, putting strips of 1-2" of rigid foam board on the stud edges with foam board construction adhesive and going with 5-6' of open cell foam would cost about the same as a 2" cc foam + 2" fiber, but would outperform it by 1.5-2x, since it would more than double the R-value at the thermally bridging framing. You'd still need a smart vapor retarder.  You'd have to long-screw the wallboard to the studs, but with say, 2" of foil-faced polyiso on the stud edges and 6" of o.c. foam it would be very close to double the performance, and would hits the performance level of an IRC 2012 code-min "R13 + 10" or "R20 + 5" for climate zone 7. That would of course complicate the finish work around window & door trim a bit, but IMHO it's "worth it", and if this were my house (which it isn't), that is the way I would go.

With any insulation solution on a house with 100 year old siding there is some risk of exterior paint failure in short years, especially if there are layers of lead paint (which are highly vapor retardent).  If/when the paint blisters & peels, scraping it down then touching it up with a matching STAIN rather than paint allows the siding to dry more evenly, with less subsequent risk of blistering & peeling, or warping the siding.  The deeper the roof overhangs are, the less rain wetting from the exterior you will have, and the less likely it is that you'll encounter this problem.

ANY heating solution depends on exactly how well you insulate & air seal the walls/windows/attic, and it's not a function of the total square footage. When the wall stackup and R-values are known, then it's possible to calculate the heat load at your 99th percentile temperature bin to come up with reasonable heating solutions.

A mini-ducted heat pump is probably not in the cards for the 99th percentile temp, since capacity falls off significantly with most of those below +5F, but with some resistance heating backup  (or a wood stove) to cover the difference when the load is beyond the capacity it can still be a reasonable solution, and would also deliver reasonably efficient (and very quiet) air conditioning.  Unless you are going something like 2x code-min performance, a highest efficiency wall coil type ductless mini-split probably won't cut it, but it might for zones with open floor plans.  (If a zone is open enough that it can be heated with a small wood stove, it's likely that a mini-split solution can work.)

A mini-ducted mini-split will run at a seasonal average coefficient of performance of about 2.5 in a zone 7 climate, a best-in-class wall-coil type would average about 2.7-2.8.  So the amount of heat delivered per kwh averaged over the season would be at least:

3412 BTU/kwh x 2.5= 8530 BTU/kwh 

So normalizing to dollars per million BTU you get:

$0.114 x (1,000,000/8530)= $13.36/MMBTU

With a 95% condensing propane burner you get 0.95 x 91,500 BTU/gallon= 87,000 BTU/gallon

Normalizing to $/MMBTU, at $1.80/gallon you get:

$1.80 x (1,000,000/87,000)= $20.69/MMBTU

Looks like mini-split heat pumps would operate at a substantial discount, costing only 2/3 as much to run as condensing propane furnaces, (though the latter would cost less to install.) Total installed cost could be comparable to propane fired hydronic heating (hot water boilers).

But it all comes down to where the heat load calculations come out, preferably using ACCA Manual-J methods,  but worst-case, using an I=B=R spreadsheet approach.
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17 Dec 2014 04:03 PM
We're in a similar situation, though zone 5/6 in Upstate NY, and with no sheathing (clapboards nailed directly to studs). The house is from the 1850s, and has a mixture of balloon and braced frame constructon, and studs that vary randomly from 4.5" to 5.5" along any given wall. The house had been through an awful renovation in the 60s where the plaster was removed, wall cavities carelessly stuffed with fiberglass batts, and 3/8 drywall placed on the inside.

We're adopting an approach that is intended to give decent performance, and be as friendly to the siding as possible.

We're maintaining a 3/4" gap behind the clapboards, and installing 2" type II EPS in each cavity, sealed around the perimeter with singles component polyurethane window and door polyurethane foam. The rigid foam boards form a kind of weather resistant barrier for the inside, and provide ventilation behind the clapboards to aid drying. In addition, they provide a degree of air sealing (though aren't the primary air barrier), and provide condensation protection for the inside surface by keeping it above the dewpoint most of the time. It also provides a rigid surface for the next part.

On the inside, we're attaching horizontal strapping using ripped 2x4s
This allows us to shim as necessary to get a flat interior surface. We're then covering the inside with insulweb, and dense packing the balance of the cavity (between the interior surface of EPS and the netting), forming a kind of Mooney wall that helps control thermal bridging. Iit'll be approx 4" of dense pack when all is said and done. The inside surface will be airtight drywall, which is the primary air barrier.

For our situation, this seemed to be the safest, least invasive, and most DIY friendly way to do it in our unique circumstances.
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17 Dec 2014 04:36 PM
Using rigid foam to maintain the back ventilation gap on the old clapboards definitely works,(but if any clever person figured out how to do it WITHOUT having to gut the interior it would really be great!)

With 2" of Type-II EPS you're at about R8.4 for the foam, and with 4" of cellulose you're at about R14-15 for the fiber, for a total of ~R24-R25 (not counting thermal bridging. That means the foam/total center cavity R-ratio is about 33-35%, which has some margin for dew point control at the foam/fiber boundary for zone 5 without interior vapor retarders, a bit close to the wire for zone 6, but it still makes it. The fact that 2" of Type-II EPS is still greater than 1-perm means it can still dry into the gap during winter, and the fact that the fiber is cellulose means any condensation events won't result in liquids on the surface of the foam- the cellulose will safely wick & redistribute any liquids that form during extended cold periods. That solution should work pretty well.

In philupthegastank's case that approach could work too. Reducing the gap to 1/4" - 1/2" would be fine, leaving ~3.5" of space for insulation (unless adding the stud edge strips for a thermal break.) He would still have to maintain at least half the center-cavity R as foam in his zone 7 climate though, at whatever total insulation thickness he opts for. That would reduce but not eliminate the paint failure risk too. Using a cut'n'cobbled foam approach without at least 1/4" of air between the foam and plank sheathing would be a bit risky, since it would demand perfection of the air-sealing of the foam (which is bound to leak air somewhere eventually.) But with the vent gap as a capillary break the sheathing can still dry into the gap- it's not a moisture trap.

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17 Dec 2014 07:38 PM
It seems like a lot of work to avoid the superior per-inch performance of closed cell foam. We use it exclusively for rim-joists in our sub-floor heating renovations here in Minneapolis since I consider it the second most important space to insulate following the attic of course.

I foamed my own 1921 balloon frame from sill plate to hot roof, improving structural integrity, sound attenuation, air barrier and an easily verifiable R-19 in the 2 x 4 cavities and 30+ on 2 x 6" cavities furred out on the second level.

Where the walls were furred out the cost of trimming the non-standard window casings was a bit more and more than complicated, even for a master trim carpenter, given the odd framing as described by others here.

If I could have added a thermal break to the framing, exterior or interior, (being a true disciple of Dana) I would have done it. But the rooms were already small and the cost of every extra inch mounts up, far exceeding ROI unless you are 100% DIY. I would never doubt the efficacy of the wall assemblies so often detailed here, but still doubt how consistently achievable they are in the real world by less-than-skilled artisans of the insulation craft, having worked with them for the last 40 years or so. There are certainly exceptions but most consumers do not demand and will not pay for the walls Dana so artfully lays out for we who will see the light.

As for mini-splits and hydronics, everybody knows I have both in home an office, but the heat pumps goes off when the temperature drops to the teens and the radiant floors make life worth living!

Most impressive as usual Dana, but not where we are at, here in Minneapolis...yet.
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18 Dec 2014 08:01 AM
Is there tar-paper or some other sheet layer between the siding and planks?  If yes, what?

Clapboards, or something else for siding?

How deep are the roof overhangs?

Is there window flashing?

The prescription to not insulate is a bad one.  Water vapor diffusion from the interior can be controlled adequately for any climate, by correct layering and materials used in the wall assembly stackup. As long as there is at least some ability to dry toward the exterior via vapor diffusion, and bulk water incursions from the exterior are limited it's possible to do this in a very moisture resilient way. It's true that insulating WITHOUT the right stackup can be risky (as in just blowing in some fiberglass can crossing your fingers), but since you're doing a full-gut rehab on the exterior shell, you have the opportunity to do it in such a way as to maintain moisture resilience.  Air-sealing-only makes sense in some situations, say, if the siding is clapboards nailed directly to the studs, but even that is addressable in a full-gut rebuild from the interior.

It's almost impossible to adequately air-seal plank sheathing with caulk, but it's possible to get there with housewrap on the interior side, which is cheaper than air-sealing with foam.  In a US climate zone 7 location if you use closed cell foam to air seal the planking it needs to be sufficiently thick that the R-value of the foam is at least half the total center-cavity R-value.  If those are full-dimension 2x4s that means 1.5" of closed cell foam is not enough, but 2" is.   But it has to be closed cell, not open cell, so that the vapor-retardency of the foam is sufficient to protect the sheathing from interior moisture drives in winter, leaving the interior side sufficiently vapor open that the cavity can still dry.

But 2" of cc foam will run over $2 per square foot, whereas 4" of open cell foam (a full cavity fill) costs about $1.50.  Performance wise the 2" foam + 2" fiber isn't much better than a 4" open cell solution.  Open cell foam also air-seals slightly better than closed cell, though both are pretty tight.

To protect the sheathing from winter moisture drives means you need a "smart" vapor retarder, which is vapor open when the air next to it is fairly humid (as happens in spring, when the sheathing warms up and releases some of it's moisture accumulation) but is fairly vapor tight when the air next to the vapor retarder is fairly dry (which happens in winter when the sheathing is adsorbing moisture from the entrained air in the cavity insulation). Certainteed MemBrain is cheaper than the difference the cost of the foam.

If you can tolerate the loss of floor area, putting strips of 1-2" of rigid foam board on the stud edges with foam board construction adhesive and going with 5-6' of open cell foam would cost about the same as a 2" cc foam + 2" fiber, but would outperform it by 1.5-2x, since it would more than double the R-value at the thermally bridging framing. You'd still need a smart vapor retarder.  You'd have to long-screw the wallboard to the studs, but with say, 2" of foil-faced polyiso on the stud edges and 6" of o.c. foam it would be very close to double the performance, and would hits the performance level of an IRC 2012 code-min "R13 + 10" or "R20 + 5" for climate zone 7. That would of course complicate the finish work around window & door trim a bit, but IMHO it's "worth it", and if this were my house (which it isn't), that is the way I would go.

With any insulation solution on a house with 100 year old siding there is some risk of exterior paint failure in short years, especially if there are layers of lead paint (which are highly vapor retardent).  If/when the paint blisters & peels, scraping it down then touching it up with a matching STAIN rather than paint allows the siding to dry more evenly, with less subsequent risk of blistering & peeling, or warping the siding.  The deeper the roof overhangs are, the less rain wetting from the exterior you will have, and the less likely it is that you'll encounter this problem.

ANY heating solution depends on exactly how well you insulate & air seal the walls/windows/attic, and it's not a function of the total square footage. When the wall stackup and R-values are known, then it's possible to calculate the heat load at your 99th percentile temperature bin to come up with reasonable heating solutions.

A mini-ducted heat pump is probably not in the cards for the 99th percentile temp, since capacity falls off significantly with most of those below +5F, but with some resistance heating backup  (or a wood stove) to cover the difference when the load is beyond the capacity it can still be a reasonable solution, and would also deliver reasonably efficient (and very quiet) air conditioning.  Unless you are going something like 2x code-min performance, a highest efficiency wall coil type ductless mini-split probably won't cut it, but it might for zones with open floor plans.  (If a zone is open enough that it can be heated with a small wood stove, it's likely that a mini-split solution can work.)

A mini-ducted mini-split will run at a seasonal average coefficient of performance of about 2.5 in a zone 7 climate, a best-in-class wall-coil type would average about 2.7-2.8.  So the amount of heat delivered per kwh averaged over the season would be at least:

3412 BTU/kwh x 2.5= 8530 BTU/kwh 

So normalizing to dollars per million BTU you get:

$0.114 x (1,000,000/8530)= $13.36/MMBTU

With a 95% condensing propane burner you get 0.95 x 91,500 BTU/gallon= 87,000 BTU/gallon

Normalizing to $/MMBTU, at $1.80/gallon you get:

$1.80 x (1,000,000/87,000)= $20.69/MMBTU

Looks like mini-split heat pumps would operate at a substantial discount, costing only 2/3 as much to run as condensing propane furnaces, (though the latter would cost less to install.) Total installed cost could be comparable to propane fired hydronic heating (hot water boilers).

But it all comes down to where the heat load calculations come out, preferably using ACCA Manual-J methods,  but worst-case, using an I=B=R spreadsheet approach.



very good post; thanks for the information and glad I came to this site...

thanks again

BTW propane rarely gets as low as 1.80 around here.  http://propane-prices.com/priceupdate.html

I know of people who spent $1500 a month on propane last year because they didn't lock in price at the beginning of the season.

Also what would you think using destratification fan in this guys old two story house; maybe set up close to his wood burning stove?
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18 Dec 2014 10:18 AM
Good link. Thank you eruling. We just paid $1.60.
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18 Dec 2014 12:11 PM
wow, thank you so much for the detailed response! I really appreciate it.

The house I bought was sold "as is" so I dont know too much information about it, but I should have mentioned that the exterior walls are 2x6 studs, and that there are new windows and vinyl siding and a new roof, from about 3 years ago. I just called the contractors that did the renovation on the exterior to get more information about all the work they did on the house, im waiting for them to get back to me. I like the idea of thermal bridging with the 1-2" of rigid foam board. upstairs that would not be too much of a problem because all of the original trim is gone anyway, but downstairs all the original stained wood trim is around the doors and windows, what would be the best way to compensate that extra inch or two of space. ( i can easily afford the 2" of wall space upstairs because the rooms are huge, but the downstairs, especially the kitchen is very small, so maybe only 1" ?) What brands do you recommend for DIY kits for the spray foam, or do you suggest to have a contractor do it?






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20 Dec 2014 06:10 PM
New England propane prices are typically getting onto twice what you pay in the midwest. Low volume users were paying nearly $5/gallon last year (average price was about four bucks), but it's backed off to the threes going into this winter.

Are those full-dimension 2x6? If yes, stud edge strips of only 3/4" of polyiso and filling it with a total of 6.75" thick cellulose would get you to IRC 2012 code-min performance.

Vinyl siding is inherently back ventilated, so there's little to be gained by creating a rainscreen gap with rigid foam.

If you go with closed cell foam you really should use a pro. If you're installing more than 1000 board feet there's no cost advantage to the kits. Most of the kti brands source their chemicals from the same place- consider them all equivalent, if you're going that route. The 600 board-foot kits are usually substantially cheaper than the smaller kits. It has to be applied in lifts NO GREATER than 2" at a time, with hours of cooling time between lifts, or there can be shrinkage/adhesion problems, or even catch fire as it's curing.

The greater R value of R6/inch closed cell foam is undercut severely by being thermally bridged by the framing. It's better to save the high-R foam budget for the thermal breaks. A flash-inch of foam would be sufficient for air-sealing and protecting the sheathing, and it can dry reasonably toward the exterior into the air spaces behind the vinyl siding, and you can then just fill the rest with blown cellulose, with a "smart" vapor retarder on the interior side.

There are usually ways to get antique window trim off without destroying it, but it's something of an art. I can't say I'm one of those artists, but I've known people who were.
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21 Dec 2014 10:49 AM


"If you go with closed cell foam you really should use a pro. If you're installing more than 1000 board feet there's no cost advantage to the kits. Most of the kti brands source their chemicals from the same place- consider them all equivalent, if you're going that route. The 600 board-foot kits are usually substantially cheaper than the smaller kits. It has to be applied in lifts NO GREATER than 2" at a time, with hours of cooling time between lifts, or there can be shrinkage/adhesion problems, or even catch fire as it's curing.

The greater R value of R6/inch closed cell foam is undercut severely by being thermally bridged by the framing. It's better to save the high-R foam budget for the thermal breaks. A flash-inch of foam would be sufficient for air-sealing and protecting the sheathing, and it can dry reasonably toward the exterior into the air spaces behind the vinyl siding, and you can then just fill the rest with blown cellulose, with a "smart" vapor retarder on the interior side."

Critically accurate information, but for the small issue of 1" 2# foam not being practically applied. Spec 2" minimum and hope for the inch.

I otherwise like this practical stack-up for renovation--where the bulk of all insulation will go in the next decade or two.
MA<br>www.badgerboilerservice.com
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22 Dec 2014 06:59 PM
I've seen installers who can hit 1" +/- 1/4" pretty consistently, but it need not be super consistent.

In this application it is primarily for air sealing the planks to each other and to the framing, which you'd be able to inspect. The absolute thickness is not critical. Even a half-inch of closed cell polyurethane runs about 2 perms, which is plenty tight enough that it is a non-wicking first condensing surface, more vapor-tight than any felt or housewrap on the exterior of the sheathing. In combination with the arleady necessary smart vapor retarder on the interior would be MORE than enough protection for the sheathing from interior side moisture drives.
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22 Dec 2014 07:21 PM
How would this "stack up" against a half inch of polyiso or XPS between sheeting and siding?

Merry Christmas Dana
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23 Dec 2014 01:54 PM
Posted By BadgerBoilerMN on 22 Dec 2014 07:21 PM
How would this "stack up" against a half inch of polyiso or XPS between sheeting and siding?

Merry Christmas Dana

Merry Christmas backatcha, Morgan!

With his stackup, a flash-foam (or 2") of closed cell on the interior would be more protective than a half inch of XPS or polyiso between the sheathing and siding. The half-inch exterior foam would have modestly better thermal performance than a flash-foamed cavity due to the fact that it thermally breaks the framing, but going with 2" of cc foam would get you half-way to the same performance (maybe more than half way for balloon framing 24" o.c.). 

Unless you're putting up sufficient exterior foam-R for dew point control at the sheathing, it's generally better to set it up for the sheathing to dry toward the exterior.  Putting stud-edge foam on the interior delivers almost the same amount thermal benefit that a full over-coat of exterior foam equal thickness would.
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23 Dec 2014 08:47 PM
Thanks for all the information and replies. I appreciate the time all of you put in to respond to my questions!

I have one more, which caulk or foam would be the best for helping to seal around windows, doors and to seal the stud cavities. Thanks.
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27 Dec 2014 11:24 AM
I do feel better now. Thank you.

Window and door foam in the can is the answer.
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27 Dec 2014 12:19 PM
Whenever possible - good tape. Because it will still work when that 1/64th inch gaps opens up to 3/64.
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04 Jan 2015 04:15 PM
heat pumps, would that be sufficient for a 2 story 2,400 sq ft house?

We've installed three mini split heat pumps in our 3000 SF "New Englander"; one up & one down in the main 2400 SF (not open floor plan) area, and one in the 600 SF north room. So far they are working great; the house is warm, the temperature has never been so even, and our oil furnace and propane boiler are OFF. We do have a wood stove for backup and power outages, and the temps haven't gotten below zero yet, so do not yet know what Jan & Feb will bring, but absolutely no complaints yet.

In terms of the guy that recommends not insulating: does he own a fuel company? What he says is correct to a point: in a building such as a barn with no insulation, moisture will dry out inside the wall cavity before it rots the sheathing. However, there are ways to prevent this from happening in an insulated building, and from a cost perspective, any homeowner would be way ahead to take the measures necessary to do this rather than heat the yard.
Bob Irving<br>RH Irving Homebuilders<br>Certified Passive House Consultant
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