DANA1: "If you need to run a WUFI simulation to figure out whether & how retrofit insulating a balloon framed vinyl clad antique is a problem, you spend WAY too much time playing the the simulation tools rather than working in the real world.

BTW: Try using a different browser- a bit of white space makes it look like you're at least taking a breath. :-) "


Firefox works better than chrome I see. Thx.

You have created quite a following I see, an internet sensation I know better.

Let's recap the thread: Op has R&R first floor plaster and lathe(my guess is lime) with 1/2 drywall. If you do not think there are major property differences especially when the interior walls are coupled to "hot water baseboards", there alone stop advising. "no vapor barrier" as far as OP knows no mold issues. My guess is probably none. Lime is an inert chemically clean stable superior hygrothermal matl. Drywall is not nor do the common vapor barriers change those properties, they make them worse.

" what to do with walls", is apprehensive about insulation based on research.

Next post "you don't need a vapor seal you need an air seal"

to follow as I said all kinds of unfounded advise with new materials that do not have the 116 year history, most with issues in less than 25.

Mine put it back as close as you can where it was. OP: 116 years, "aint broke don't fix it" Since there is no local prescriptive successful path here that has been sited that is the best advise.

The second best choice WUFI. In a fraction of the time it took to generate this confusing thread a novice could have modeled the home using the building wizard and the auto-populated databases to include local climate files. Sketch-up or gbxml file imports make it even faster. The software cost less than $500/yr, the learning curve is not that steep. The amount of info and outputs is much more accurate than this thread or any blog.

The blog writers and popular poster would rather you not use the better tools, go to them to buy their products. WUFI articles on GBA usually focus on it's failures, and it being impossible to learn even by PHDs....Man go back to physics 101.

DANA1: I have no idea how you that has no building design experience obviously running CFD can make a determination which produced better clear accurate results. As in the case of this thread or WUFI. The answer to the average laymen s/b obvious, especially if you download the free versions and look around you will see you don't need an internet advisor or blog. You spend WAY to much time in a "real" dream world trying to get people to follow your way with no proven tested builds to speak of.

BIMs interface is slowly gathering the local prescriptive database you refer to that today does not exist in the US for the most part. In it you will find softwares that captures building lifestyle data to design-build-inspect-sustain to. gbxml is the one interface between WUFI and the design model but is not need using the easy wizard, local jurisdictions, pro's, need to adopt.

My structural engineer blessed the belt-and-suspenders envelope design of my home (now finished) with this definition of his role: Anyone can build a structure that stands; it takes an engineer to build one that barely stands.

So instead of spending $500 for software he uses once, why doesn't OP overdo his wall R&R to eliminate any doubt, with the additional benefit of greater efficiency? 1.5 inch polyiso sheathing, carefully sealed and flashed, is a good answer in new construction. (Right, Dana1?) Checking Craigslist for reclaimed board, $500 gets me about 1,500 sf. I'm thinking OP isn't wild about a siding R&R but you get my point. Overdesign is an acceptable answer.

WUFI has serious "garbage in = garbage out" problem, especially in the hands of the untrained. In the hands of the trained it's sufficient, sure but it's certainly not necessary.

Using a EE analogy, it's sort of like saying you need to run a SPICE model of the circuit to design a stable class-A amplifier when it clearly doesn't. Yes, there are some time where the simulation is critical, but for the vast majority roughing out the zeros & poles on a single sheet of paper to know how much margin you have is more that adequate, and often even that much analysis isn't necessary. And, inexperienced EEs screw up modeling inputs all the time, and tend to put too much trust in the models.

The IRC have prescriptives Chapters 7 & 8 of for wall & unvented roof assemblies when using only Class-III vapor retarders, spelled out by major climate zone. See Table R702.7.1...

http://codes.iccsafe.org/app/book/content/2015-I-Codes/2015%20IRC%20HTML/Chapter%207.html

...and Table R806.5 :

http://codes.iccsafe.org/app/book/content/2015-I-Codes/2015%20IRC%20HTML/Chapter%208.html

The OP's vinyl siding meets the IRC definition of "Vented cladding" in the chapter 7 prescriptive.

Nylon (such as MemBrain) hasn't been around for 115 years, but it's been around for over 80 years, commercialized for over 75, and doesn't have degradation issues when it isn't exposed to UV, high acidity, or high temperatures. If it's still deemed too risky by the OP, half-perm latex works.

There are balloon framed houses in Saskatchewan (zone 7-ish) that have been insulated with cellulose for over 100 years that are still in good shape. The vapor retardency of oil paints may have helped with the longevity of some of those but not all many were simply wallpapered. There are many thousands of houses in zones 5-7 retrofitted with cellulose that are still standing 50+ years later. I've personally seen some of those houses gutted from the interior 30+ years later with the insulation looking like it was installed yesterday, with no apparent moisture issues on the sheathing (both & plywood.) If that practice has been a death sentence it would be interesting to know where the bodies are buried.

And, the hygrothermal analysis (whether simulated, prescriptive, or practicum experience) is missed the largest risk entirely:The single biggest cause of moisture problems in retrofit insulated buildings and new is (by far) inadequate bulk water handling details, not vapor diffusion.

To meet current IRC code the OP's wall would need Class-II or tighter interior, not that it's particularly risky if it's air tight, especially if the cavity fill is cellulose, unless the bulk water handling details aren't adequate.

BTW: My degrees are in physics & math- don't need Physics 101, but thanks for the suggestion. :-)

Until/unless the OP weighs in, I'm done.

LMAO! Never hire a structures or EE to do a CFDs job. It's been entertaining, much better than reading Trump tweets and Saturday night live

Dana has been one of the better contributors on this site helping people here for many years. Para you just show up and attack everyone. People who come to sites mouthing off while hiding their identity are either company bots or trolls. Not sure which one you are but you are another dirt bag arsehole for sure.

If you check parahomes on the interweb it comes back as an shaggy carpet company in India. May we call you "Shaggy"?

Posted By Bob I on 01 Dec 2016 10:24 PM
Mr Para: My remarks were ill conceived and made in haste. I apologize. You are obviously an expert in some of the murkier areas of building science, and could be very helpful in bringing some understanding to the readers at this site. Most of the people posting questions are DIY; some with very little idea of building science and some we versed, but probably not in the details you know about. Maybe you could suggest practical ways that would help on their project. And demonstrate why understanding and using PHIUS principles is beneficial to them.

Thanks Bob, I've learned alot from the Germans and a 30-year global design background of sorts. As you can see explaining PHIUS principles to people that know little to nothing or care to is an impossible task. I enjoyed your videos. I did the same using my Architectural model, HVAC software where I show my ERI of zero, and WUFI model on my website. The biggest challenge trying to simplify complex building science like some out here fail to do in practical terms was best demonstrated by walking through the complete design processes in a video series. I used a Passive spec demo.  Hoping here this approach crushes the competition offering junk at a premium price.

Marketing that and getting clients on board another story. Another, getting accurate appraisals and lenders on board as you know. As you know, putting your reputation, business, money, legal liability behind your advice is MUCH different than posting and blogging on "Green" sites. In the short time I have been out here I am amazed how many building failures there are from lets call it "ill conceived" advice.

Sad to see little activity on WUFI forums I and others hope to improve. We are a small nit national group that needs to maintain PHIUS integrity and accuracy replacing bad advice with it for those that are willing to learn and pay a price for, ignoring the rest and ignorance. That will grow our local communities so practicing professionals like you and I can grow the national green industry and sites like this.  Good to see Joe and BSC is behind it now, although some pick and choose when to be in "his camp".  Also, good job John Straube, Chris Schumacher, ASHRAE 160 committee, NREL, and other credible sources

I been chatting with the Germans lately about some new plug ins coming up. In my experience it's excellent software PHIUS has chosen no single person can compare to it's accuracy. I'm sure you are wise enough to know that. The newer plug-ins like WUFI_BIO takes a conservative approach to mold growth as the OP is concerned about for retrofits it would answer accurately. I been trying to find out when the others will become available and looking forward to it.

Keep up the good work!

https://wufi.de/en/software/wufi-add-ons/

 

As you can see explaining PHIUS principles to people that know little to nothing or care to is an impossible task.

I don't think it is at all impossible, but the methods you've used in your posts on this website is not the way to educate anybody. Berating and insulting people you don't know simply turns them and everyone else off and brings down whatever you are suggesting. The above posts demonstrates that you can, in fact, write pleasant, un-insulting educational posts. Please keep this up & drop your attitude and insults and assume that you are talking to intelligent folks who are trying hard to understand how to do the best job they can with the constraints they have. You can disagree with advice, as many of us do, and suggest other methods, without being disagreeable. And thanks.

Please keep this up & drop your attitude and insults and assume that you are talking to intelligent folks who are trying hard to understand how to do the best job they can with the constraints they have.

I only targeted DANA1 since I know he is intelligent enough to understands when he is wrong and I could have keep going and you, ignoring the rest. I don't believe most are really trying to understand or they'd at least download the free versions. I can tell DANA1 that talks to WUFI has no experience with it or "is trying hard to understand" what the Germans, John Straube, Chris Schumacher, ASHRAE 160 committee, NREL, BSC, and other credible sources have known for decades represented in WUFI.

Now I'm done wasting my time here. Have better things to do like get better at WUFI_BIO.

Most people know nothing about WUFI except what you have said in your posts. Why don't you explain it; why it is useful and discuss how easy to is to use and the cost.

Still feeding the trolls, are you Bob?