Our project is a balloon framed farmhouse (2x4 walls) in Northeastern Pennsylvania, zone 6. All plaster and lath has been removed, and is being replaced with drywall on the first floor exterior walls and finished attic, and 3/4" wood plank on the second floor. Exterior is 3/4" plank, clapboard, and then vinyl siding WITHOUT exterior foam board Heat is hot water baseboard. There is currently no vapor barrier or insulation. I have already installed durovent in the attic and will be heavily insulating the roof, which will be vented with a power vent (metal roof does not have a ridge vent). I will also insulate box sills in the basement with foam board. So the big question is what to do with the walls, if anything? We have read a number of things against insulating, and on the other hand have contractors who are more accustomed to modern building techniques. My attitude is that if its not broken, don't fix it -- but I'm not sure if that holds true where we have removed plaster to replace with drywall, with its different properties. I am also not terribly concerned with the increased heating cost if it means that our house will not introduce mold and moisture problems that the house has avoided for 116 years. We also do not mind a cooler house. So, what vapor barrier/insulation combination is best, if any?

RE:
"contractors who are more accustomed to modern building techniques"
"if its not broken, don't fix it"

Do you mean contractors who are NOT familiar with modern techniques, and still use the failed & broken methods of the last sixty years? Like those that cause mold and other problems?
Most of the "code" (meaning cheapest legal way possible) builders I know have no clue about the right way to build, use outmoded building techniques and continue to foster those failed houses on their clients.

You don't want a vapor barrier - but you do want an air barrier. Insulation is one component of a livable house, but without an air barrier the insulation is close to useless. Think of being outside in January when it's -15 and extremely windy - a loose weave wool sweater won't help much without a wind breaker. Your house needs the same thing. Insulation works great in an air tight enclosure. Since you are not installing - and taping - foam board*, here are two good methods you could use. Keep in mind that your interior and exterior sheathing - "3/4" wood plank" is like a thin wool sweater in that it is extremely leaky in regards to air movement. The ideal situation would be to sheath over the boards on the exterior with ZIP sheathing and tape the seams. That way the stud cavity contains still air and works to insulate the house, rather than simply filtering the air passing through. After insulating, install Membrain or a European material like Majpell (PerformanceBuildingSupply.com or 475.com) to stop air movement, while allowing water vapor (the stuff that causes mold) through the fabric.

Check out this site: http://www.greenbuildingadvisor.com

*Roxul Board is very permeable, an excellent insulation material, and repels water, rodents and insects; a good substitute for exterior foam.

what to do with the walls {without exterior access}

I would fill them with damp sprayed cellulose, then a layer of rigid foam (well taped to air seal, reduce thermal bridging and possibly provide the vapor retarder) and then drywall or wood on the interior.

Passive or highly insulated buildings are characterized by extremely low energy consumption. Dynamic hygrothermal models are necessary to accurately model the hygrothermal behavior of buildings in dynamically changing climates or climates where cooling and dehumidification of the indoor air play an important role. Thermal and hygric inertia must be considered in detail to further reduce energy demand and to eliminate limitations on indoor comfort (e.g. overheating).

In many climate zones, the use of highly insulated components presents risks – such as moisture issues to designers and construction professionals. Managing this risk requires a dynamic hygrothermal assessment under real climatic conditions. Anything less is guess work at best with 1000s of opinions based on internet profiting including mold growth. It's not as simple as some want you to believe or found on forums or blogs. Mistakes can be VERY costly and/or uncomfortable.

"but I'm not sure if that holds true where we have removed plaster to replace with drywall, with its different properties. I am also not terribly concerned with the increased heating cost if it means that our house will not introduce mold and moisture problems that the house has avoided for 116 years. We also do not mind a cooler house. So, what vapor barrier/insulation combination is best, if any"? "" Your house was more than likely free of mold issues like most back then due to inert hygrothermal mass(lime/clay, etc) you replaced with drywall, not needing a vapor barrier. Sounds like you need pro help, adding heat addition to fungi foods found in lots of products today, including ZIP/foam(not inert), plastics, glues etc, moisture creates mold issues if the vapor barrier and type is not placed correctly which 9xs out of 10 is this case since there are no rules of thumb that work in high performance homes. I guess there is a common misconception taped and clued together air tight buildings will last forever even when vapor barrier clues(tapes, glued foams, etc) under hot-cold & structural cyclic fatigued and the air seal will last forever or the building will never have to be largely disassembled when they fail and they will to get the seal back...There is no life cycle testing on the mfg websites since it is too complex. Thanks to those that are doing the mfg field climate zone testing for them/us.

The mass you replaced needs small air to dry a vapor or air seal would ruin and loose the latent heat/storage bene drywall and others have none to little. There is no money to made by internet sales on lime/clay with moisture holding capacities 30-40% ther volume, that for example lime gets better as it sees CO2/moisture unlike drywall, zip, osb, glue, foams, etc....and takes down your heating/cooling loads some by latent heat of evaporation and condensation, reducing or elimination hot-cold spots, etc, other materials will not. Lime plaster is cheap, it's a loss skillset finding a good trades person at reasonable cost might be the issue.

If you can't afford to hire or find a local pro green building engineer(usually not builder or sub-contractors) that knows the climate, as you said if it aint broke like many today will be in much less than 116 years, put it back as close as you can to the way it was. Mineral wool insulation is a good choice.

Posted By Jason123 on 24 Nov 2016 12:16 PM
Our project is a balloon framed farmhouse (2x4 walls) in Northeastern Pennsylvania, zone 6. All plaster and lath has been removed, and is being replaced with drywall on the first floor exterior walls and finished attic, and 3/4" wood plank on the second floor. Exterior is 3/4" plank, clapboard, and then vinyl siding WITHOUT exterior foam board Heat is hot water baseboard. There is currently no vapor barrier or insulation. I have already installed durovent in the attic and will be heavily insulating the roof, which will be vented with a power vent (metal roof does not have a ridge vent). I will also insulate box sills in the basement with foam board. So the big question is what to do with the walls, if anything? We have read a number of things against insulating, and on the other hand have contractors who are more accustomed to modern building techniques. My attitude is that if its not broken, don't fix it -- but I'm not sure if that holds true where we have removed plaster to replace with drywall, with its different properties. I am also not terribly concerned with the increased heating cost if it means that our house will not introduce mold and moisture problems that the house has avoided for 116 years. We also do not mind a cooler house. So, what vapor barrier/insulation combination is best, if any?

In a zone 6 climate even if you dense-packed the stud bays with cellulose (recommended), and have inherently back-ventilated siding (such as vinyl, which is also adds resilence) you would still need an air tight interior, and a vapor retardency of less than 1-perm in winter. Half perm paint aka "vapor barrier latex" primer is adequate for your stackup, provided it's air tight. More expensive but also more forgiving would be to use 2-mil nylon (Certainteed MemBrain )just behind the wallboard. Thin nylon is less than 1-perm when the entrained air closest to it in the cavity has low humidity, which it will be in winter, but becomes more vapor open than standard latex paint if the humidity goes high, as it will when the plank sheathing warms up in spring, releasing it's wintertime accumulation. It's not a bad compromise at 12-15 cents per square foot.



Open cell spray foam can be cheaper and more air-tight then dense packed cellulose, and a reasonable alternative. That too would require something to lower the wintertime permeance to the interior, such as 2-mil nylon or half perm paint.



An important thing to get a handle on before insualting is the window flashing details. Many old uninsulated farm houses had no window flashing at all. If wind blown rain got by the window, it dried quickly in empty balloon framing, but once you insulate that doesn't happen. With deep roof overhangs the risk is small, but if there's no window flashing you may take a different approach on those stud bays than the others. Fiberglass blowing wools dry faster than celluose, but if you have chronic bulk wetting it's still an issue.



Do NOT power vent the attic- EVER! Power venting the attic reduces the pressure in the attic relative to the occupied space, drawing air up from conditioned space, which in turn forces outdoor air infiltration into the conditioned space. The effects on cooling energy is usually to increase the overall load and power use.



If you're insulating the roof (and not the attic floor), why are you venting the attic at all?

Dana 1: Do you have any proven design-builds per your above design recommendations in PA as or have you ever been there? If so post them as in the address and client name you designed-built for and when? Also, what was your initial cost to build and what did your build appraise at or better sell for? Perhaps you put a spec/model there with some of your own $$$ or can put some real skin behind your massive internet post and blogs? How much did the bank you dealt with want down or what was your LTV, who did your construction and perm financing? I take it your a national designer with proven designs across the nation in every climate zone or are you just guessing and misleading people because based on your last post the is VERY obvious to me? The only logical answer you have is to post your design of this particular home, 3D design models & drawings of ANYTHING you have done and proven in this climate zone and a complete analysis of zonal room temps/humidity levels and mold potential to begin with? If you are as you want ppl to believe static is not going to cut it, common really? Save that for a misleading blog over at GBA & the DIY market that knows no better. Who pays you to write all day, are you retired with nothing better to do with no other way but to supplement social security income attempting to ruin local green building engineers and knowledgeable builder/designers markets and need? You must be sponsored by the same mfgs @ GBA to spread it over here or any "green" site DIYs willing to be mislead by sponsored advice to mislead people with products that may or not work, as in your recommendations have no proof since you have never designed-built in PA? How else can these "GBAs" pay the bills, common ppl!! Or most if not any of the climate zones you have no "real" experience in? If I am wrong and you really are a great knowledgeable green design engineer with massive multi-climate non-sponsered and the best advice here and/or proven designs credentials to be an "nationally recognized green building adviser" please post the addresses of your builds on your website??

Posted By Jason123 on 24 Nov 2016 12:16 PM
Our project is a balloon framed farmhouse (2x4 walls) in Northeastern Pennsylvania, zone 6. All plaster and lath has been removed, and is being replaced with drywall on the first floor exterior walls and finished attic, and 3/4" wood plank on the second floor. Exterior is 3/4" plank, clapboard, and then vinyl siding WITHOUT exterior foam board Heat is hot water baseboard. There is currently no vapor barrier or insulation. I have already installed durovent in the attic and will be heavily insulating the roof, which will be vented with a power vent (metal roof does not have a ridge vent). I will also insulate box sills in the basement with foam board. So the big question is what to do with the walls, if anything? We have read a number of things against insulating, and on the other hand have contractors who are more accustomed to modern building techniques. My attitude is that if its not broken, don't fix it -- but I'm not sure if that holds true where we have removed plaster to replace with drywall, with its different properties. I am also not terribly concerned with the increased heating cost if it means that our house will not introduce mold and moisture problems that the house has avoided for 116 years. We also do not mind a cooler house. So, what vapor barrier/insulation combination is best, if any?

Here I'll quote the OP like that matters..... Dana1. Your answer..... Dana 1: Do you have any proven design-builds per your above design recommendations in PA as or have you ever been there? If so post them as in the address and client name you designed-built for and when? Also, what was your initial cost to build and what did your build appraise at or better sell for? Perhaps you put a spec/model there with some of your own $$$ or can put some real skin behind your massive internet post and blogs? How much did the bank you dealt with want down or what was your LTV, who did your construction and perm financing? I take it your a national designer with proven designs across the nation in every climate zone or are you just guessing and misleading people because based on your last post the is VERY obvious to me? The only logical answer you have is to post your design of this particular home, 3D design models & drawings of ANYTHING you have done and proven in this climate zone and a complete analysis of zonal room temps/humidity levels and mold potential to begin with? If you are as you want ppl to believe static is not going to cut it, common really? Save that for a misleading blog over at GBA & the DIY market that knows no better. Who pays you to write all day, are you retired with nothing better to do with no other way but to supplement social security income attempting to ruin local green building engineers and knowledgeable builder/designers markets and need? You must be sponsored by the same mfgs @ GBA to spread it over here or any "green" site DIYs willing to be mislead by sponsored advice to mislead people with products that may or not work, as in your recommendations have no proof since you have never designed-built in PA? How else can these "GBAs" pay the bills, common ppl!! Or most if not any of the climate zones you have no "real" experience in? If I am wrong and you really are a great knowledgeable green design engineer with massive multi-climate non-sponsered and the best advice here and/or proven designs credentials to be an "nationally recognized green building adviser" please post the addresses of your proven builds on your website?? I'd like to see on your site where you take legal liability for your designs as most local Architects and Engineers do?

Obviously someone very high up in the humanity chain has died and left this obnoxious know-it-all be the end all to every scientific principle ever discovered by anyone and everyone in the past 100 years give or take a decade. I have had the displeasure of the experience of listening to several individuals in my life that were self proclaimed brilliant beyond human capabilities and superior to everyone else and their ideas. Never like this. It is truly disheartening to read this blog. I have never said anything like this to another person but this one deserves it. I have enjoyed reading the diverse ideas and opinions of contributors of this blog for quite a few years and appreciate everyone who has spent their valuable personal time to share their wisdom, knowledge and experience to help others who are trying to do the right thing for themselves. Thank you to all. I will be terminating my connection to this forum and hope you all have many successes in your lives. Some of you have my e-mail address and you are welcome to contact me at anytime. RichM

Parahomes,
I've got to say that you're the biggest ass I've ever seen on this site, attacking someone without provocation, someone who has provided reams of engineering-based advice for years to people that use this site. Your attacks are like those of a madman striking out at shadows. You question his capabilities, you throw out suggestions that his advice in not impartial, you attack other reputable sites, all without reason. Obviously you have a self esteem issue far beyond anything I've ever seen in a person. Go ahead and spout all of your "hygrothermal analysis" crap. I doubt you could even run the equations. No you're the type of guy that blusters his way into a situation and then generally doesn't deliver. I sure as hell feel sorry for your supposed customers if you really have any

RichM That is exactly what this ass wants. Stay on man!

Parahomes,
I've reread some of you previous posts. Sounds like you're an extemely well-educated person of the type that could pull off some great scams spouting all the intelligent sounding banter. I've had the displeasure of knowing people like you. Business investment schemes and all. Yeah people on this site shoild quit helping DYI'ers and go for the brass ring etc etc. Tell you what, this site just doesn't measure up to your standards, being so intelligent, so why stick around it?

Parahomes, I can attest to one of Dana1's builds....I communicated years ago with Dana1 about the home I was going to build in a unique microclimate on an island off Rhode Island, Dana1 was amazingly generous with his time and knowledge and we spoke by phone several times as well. I took a good deal of his council and based much of my house design on it. I'm not a "DIY hack" I'm a registered architect with 40 years of building experience (I've overseen more than 1/2 Billion dollars worth of construction). But I like to kick around new ideas with smart, knowledgable people - I'm still learning. My house is going into it's second winter now and the fist winter (and summer) was great. The building performed better than I expected. My biggest issue was moisture control in a climate with dense fog and near 100% RH most of Spring and Summer plus horizontal rain (and a wife with severe mold allergies). I have R37 walls and R60 roofs and I have no moisture issues at all! Dana1's take was dead on. I did not run a dehumidifier in my basement all summer and I have no mold or mustiness and I'm willing to bet mine is the only house of 1800 on this island that does not have a moldy basement. It's now November 29th - I turned the heat on for the first time two days ago - but really didn't need to (wife complained at 66). I credit myself with a good deal of the design and the final decisions were mine - but Dana1 provided (at no cost to me and no profit to him) great information, great insights into building science theory and a terrific "sanity check" on some of my crazier ideas - for which I am eternally grateful. His generosity is remarkable! Thank you, Dana! Meanwhile, where the Hell were you?

Is there any way to "Ignore" a poster? PARAHOMES obviously doesn't get the concept of this board. Dana offered his advice based on his expertise and experience. The OP is free to accept or reject that advice, or to ask more questions to gain additional insights/opinions.

You see PARAHOMES, it's about exchanging ideas and looking at things from different angles. Its not about pushing an agenda or stoking ones ego. Your personal attacks on a valued contributor are out of place and not welcome.

Just as we are all free to accept or reject advice, so are we free to ignore some posters. Instead of leaving the site in protest of a poster, better to just ignore. They will leave on their own if we don't respond. Just wish there was a button to push to make that easier.

3CityBlue - well said!

I'd put a lot more trust in statements based on good research (eg, Building Science Corp) than anecdotal data based on a few, poorly instrumented houses and unpublished data. On the other hand, there is occasionally poor research and over generalization. For example, everything I've seen on power attic ventilation is based on the ridiculous use of exhaust only (vs push-pull, causing no depressurization).

I agree, ignore ad hominem attacks.

"Dynamic hygrothermal models". Let's get them to model a Manual 'J' on new constuction... I used 2# foam from ridge-vent to rim-joist in my plaster-off 1921 farm house. Beyond the obvious structural and sound attenuation improvements comfort could only be improved by the addition of triple-pane windows. Though the lower heat load might cool off the floors. More modeling needed...

Since Parahomes is generalizing so much on a much more complex topic than a few posts can address, I will as well.
Parahomes, your comments indicate frustration, perhaps a lack of business sense and desperation, from the sounds of it you cant get financing and you believe the root of all your problems are forums such as these where those with knowledge share it and somehow its hurting your finances when the reality of the problem is you and your lack of knowledge obtaining financing and the process in general. Shutting down the sharing and building of knowledge isnt going to create a green engineer industry you have such a hard-on for.

Who on earth would post client names and addresses on a forum? That's ridiculous and no builder has time to build case studies, we try new things, seek advice and try to make the next one better, sometimes successful, sometimes not. Will net zero houses appraise to build cost...probably not thus homeowners seek to diy some of the cost prohibitive extras that make a house better, they have no choice. Sometime the builder cost and ROI doesnt make sense, again thats where these forums come into play...owner equity. Ever notice how alot of featured high performance homes and net zero homes are featured in architectural blogs and journals with high end finishes? Most likely cash builds. Its hard enough to get standard new homes to appraise in certain situations.

I too at times have wondered Dana1's motives or angle to his incredibly detailed posts and remember when he first started posting many years ago. Over time it has become apparent he really is doing a great job helping people and he has become a value to GBA and this forum. Occasionally we all might suggest something that sounds good from a desk but doesn't work in the field, but sorting that out is how this "grassroots" community works.

To summarize my thoughts..you need to chill out, contribute concisely as an engineer should without emotion or piss off.

Clearly I'm NOT to be trusted- I even use my real name! :-) (The "1" was only 'cuz some deadbeat "Dana" beat me to the moniker here.)

... and just make it up as I go along (or link to IRC prescriptives &/ or building science analyses of how things really work ad nauseum.)

Dana, I was giving you *())&^ it's ok I know all about what you post. If you all have not seen the site PHIUS, for loads I run the WUFI passive cert modeling and Plus, also Beopt, nationally, do my own Architectural designs and drawings as a design-build firm, own several degrees & licenses. It ticks me off to see ppl like Dana1 and GBA simplify it to DIYs that know no better. I guess PHIUS should just throw a "perm here and there" or thoughtless "r-value" here and there, meaningless statics, based on some erroneous state wide climate zone, neglecting the actual dynamic environmental surround loads of the home. Forget all the hard work others have done based on this sales hype! Above you will even find suggestions by a "certified PHIUS consultant" that took the classes should know better than this. Blindly air/vapor seal this and that. This takes down the need for local business, green engineers and architects actual pros, PHIUS, etc..... I've done recent US market analysis, in concert with Metrostudy the green home movement is moving very slowly. Seems Dana1 and others moving GBA backed products, perhaps making a living on "green" DIY advice is reaping short term profits. In the end, if the local infrastructures that should know the best about their designs and products some of which like lime plasters are cheap and superior cannot profit this whole green movement will die, including this site. Don't believe for a sec unless your IAQ has been professionally tested and continuously monitored all is well. That is a science in itself not engineered online, WUFI is a start. We in America for sealed passive homes need to start with it. There is a TON of info in it, like in Wufi-Wiki to learn. Once you get into the free "static" Passive version at least you will have a better appreciation what I am talking about. The labs like ASHREA, NREL, massive data, etc has the tested builds in the software. You cannot replace it with a forum or blog guessing. If you really think that call PHIUS convenience them all we need is forums and blogs drop dynamic modeling that has been proven for the most part globally accurate for the better part of 20 years. Blog writers prefer you go back to them. Our dynamic air/vapor flows in US, it is not that simple. At the end of the day, we want advice that is climate specific by pros in those climates based on many output reports. That grows the industry. Add all that to what green homes are nationally appraising at in the local areas, not doing well, there is too much to know to act as a national expert, there are no such thing unless they have built and sold them all at the passive level which does not exist. Nice try, my name does not change the facts want to know PM me give me your #. I speak the truth from experience I'll stand behind when we talk. Can't wait for someone with some balls to call me ass for that. I actually travel the US doing design jobs on contact consulting that pays me well, could be in a town near you soon. Just got home in the central plains from PA six months ago, Dana1 your advice probably more than likely wont work there, after having some fun in San Diego, CA and north of it on assignment(DANA1 you'd have better luck there) as in the high desert where I was and any moisture dries out in less than 10 mins most of the year. 3 hours south or north of that or Philly totally different, state codes don't work so please stop!. Peoples health and lives depend on it.

I wrote a long entry, but deleted it. You give PHIUS - a great organization, started and run by a great visionary, a bad name. Shame on you. I'll also mention that unlike yourself, I am not afraid to use my name. Unlike you, I own what I say, mistakes and all, instead of hiding behind a fake.