Breathable Walls

Really great breakdown of a lot of complex and interconnected data here Terry. A lot of this stuff is over my head in terms of depth, but as an amateur builder, stuff like this is invaluable (if a bit overwhelming at times haha).

Though I love considering these ideas in the context of future builds, I'm also trying to adapt the information to my current house, which was built using conventional building modalities. As I redo different areas and retrofit more insulation and thermal/hygroscopic mass I try to take into consideration how those natural materials (be it earthen plaster, straw, or something else) integrate into the house as it stands. One question I have for you is about basements/crawlspaces and vapor barriers. My house sits over a crawlspace with no vapor barrier on the sand floor. The previous owner shoved fiberglass around the perimeter, but at the current temperatures condensation has actually caused the outer layer of the batts it to freeze to the sill plate and concrete foundation. Since the concrete does not really seem to "breathe" in the same way as the natural materials we're discussing here, do you feel that air sealing around the perimeter (as I have done with the vents) will cause an issue with humidity. Particularly given that I am not looking to spread 7mil plastic across the ground.

I know that full basements/crawlspaces are a bit of a new development in building history for better or worse, so I guess I'd mainly like to hear your thoughts on working with already-existing basements and concrete foundations to minimize humidity and air quality issues while maintaining a decently-conditioned space that doesn't suck the heat out of the floors.

Thanks,
Kieran

Hi Kieran, yes this book is very technical in the beginning to proof the issues with conventional building methods that dominate these days, and to provide some natural material properties, and I think it did a great job.

I can offer what the authors position on crawl space seal vs non getting popular lately and add that the books position makes sense to me anyway. I’ll try and simplify.

They are not fans of crawl spaces at all, especially permanently seals ones, due to moisture issues noting them as “mold factories”.
Reasons: The soil plastics often never seal no matter how much one tries, that last. Attempts to control ventilation fail (reminds me of attics). Air ducts pull soil gases and mold spores into the air stream and leak moisture promoting condensation to the inner stem wall. Rigid foam boards trap moisture to the stem wall.

Simply put they recommend keeping the crawl space temperature above the soil temp due to vapor pressures differences or drive that will dry to exterior air. In cold climates like MI, where soils can get below 55-60F seal and insulate the vents and seal off the CS for the winter months only. The other seasons make sure there is plenty of air flow even if you need to run a fan.

Ideally is a soil level that is higher inside than grade, if not insulate the rim joist. Get rid of the fiberglass it does not dry out fast enough, when wet large reductions in r-value. cotton or mineral wool, limecrete, do well. I made up a limecrete pozzolan with straw-type S hydrated lime, and fly ash from my coal firing plant, type C, that stuck to conventional studs and sheathing very well, it air sealed too, see below, it will not condense moisture at the sills and make help as a capillary break if you do not have one. Then I insulated with tight fitting mineral wool batts. For hard to reach areas a mortar applicator can be used. Get them at Lowes or Home Depot. Much better than open cell foam sprays. If you have ducts try it to seal them or find a low voc mastic.

Rather than a plastic floor, try 70% bentonite clay, 25% magnesium oxide, 5% borax a thin milk like mix spray it onto all crawl space areas as a breathable water proofer; If you are close to a water table use a sump pump. Crushed rock can clog drain tiles and pea gravel back-fills over the years.

As far as humidity a modern psychrometer – moisture meter would tell you a lot, such as the RH of the crawl space we want around 50, and inside your house. Like walls there are material that regulate this level, AAC block would be one if your stem wall were made out of it but it wicks a lot of moisture from a water table and needs a good break. That could be your problem, capillary uptake.

I am shopping around for one here is one I found that looks decent: https://www.youtube.com/watch?v=qat9Nqs8KDw

I’d locate the moisture issues rather than seal, find out what your ground temps are compared to the CS and correct that keeping the CS slightly higher. Check the humidity in the CS keep RH around 50. Make sure you have good ventilation in the spring, fall, and summer. Get better insulation if your rim joist is exposed to the exterior. Add the water proofing to promote drying and reduce capillary uptake from the soil and/or footings, stems, blocks, etc.

There is a lot of other great advice in the book but out of respect for the authors I won’t give it away. The foundation chapter is easier to read than the beginning, offering good advice on basements and slabs without the use of plastics and foams popular today.

I use this easy to use site soil map to get an idea how drain-able and expansive soils are, where the water table is, etc: http://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm

This is a garage room addition I sealed without the use of very toxic OC spray foams.. little more labor but worth it. Water vapor or liquid water will not condense here or on the rock wool.

Yes Terry, I have a lot of catching up to do in terms of understanding building techniques, but a major component of what I've currently learned is that crawlspaces/basements are likely not the way to go. I like their term: "mold factories."

If you don't mind, I'm going to regurgitate some of the information you just shared back at you to make sure I've understood correctly. Some years ago it seems that an updraft furnace was installed in place of a downdraft furnace in this house, rendering the ductwork in the crawlspace pretty much useless. I began to tear some of it out, and have just been sealing the vents. (I heat with wood so Keeping the crawlspace above the soil temperature makes sense to me, so after I've insulated and sealed the rim joist better, maybe I should remove the old fiberglass from between the joists to let the crawlspace just steal some of the home's warmth? That way my water lines will be better protected as well. I've been doing some reading about the Korean Ondol design and I do wonder if that could somehow be integrated with a modern crawlspace design. Or as a retrofit. I'm not that interested in installing such a system in this home, just something I was thinking out loud about. I also haven't weighed the cost/benefit of it against conventional radiant floor heating though, nor do I know what the traditional system would have used on the ground. Presumably a rock/rubble medium, but then again, moisture is probably less of an issue when you have a fire burning at one end and sucking air out the other.

My main question about what you sad though was regarding the limecrete. It sounds really interesting but I'm not sure I entirely understand what you did in the picture below. If I've understood well, it seems that after mixing the limecrete you simply plastered it along the sill plate and in between the joists, and then once dry you stuffed in the mineral wool? I could easily reach into the cavities between the rim joist and the floor joist to pack plaster in there. It seems like that would stick to the concrete stem wall as well as the lumber as you said, but I suppose I could also use building paper (or even something like burlap potentially?) to cover the wood if the plaster was pulling away.

As a final question: is the book available for sale yet? I found the 2008 edition for sale on their website, but it seems that you're discussing a more recent edition. I'd love to read through it more thoroughly, although I can tell you're doing a great job relaying a lot of the information. Sorry, don't mean to hijack this thread. Carry on delivering information from the book.

Best,
Kieran

Terry

Really appreciate your detailed comments. Science can sure get intricate and it looks like you're spending lots of time in study hall! One thing you mentioned to Kieran struck me, though:

> crushed rock... plug drain tile

I believe that may be true depending on the percent of "fines" in the crushed rock. However, current practice as I understand it specs the use of _washed_ crushed rock for drainge, meaning that essentially all the fines are washed out leaving only the large pieces. Crushed rock is preferred over naturally occurring gravel because it has many more sharp angles and edges which create more and larger spaces between particles for liquid water to drain through. But _washed_ gravel of any kind should not plug the drain tile.

FWIW regarding drainage. I have read one engineer who designed fill and engineered drainage for big dams and road beds in the 60's claim that concrete sand (what is used to mix concrete) performed far better than any other fill for drainage. He returned to projects 20 and 30 years later and made a point of checking whether his fill has remained stable and continued to perform to direct moving subsurface water properly. He views gravel/crusher-run as a special purpose fill that is grossly overused. Cement sand is spec'd to have sharp angles and corners just like crusher-run; both are spec'd for load bearing structural purposes because the particles tend to lock and hold together better than smooth sand or rock; the sharp irregular pieces also allow excellent drainage. But the reason he prefers sand for drainage is that it does not "silt up" as much from the surrounding earth diffusing into it. I don't know all the science but apparently the relative size of the particles in each kind of earth or fill has a huge influence on whether on not the boundary between to two types remain open to water flow over time. Gravel boundaries with earth tend to silt up as the earth migrates into the relatively large gaps in the gravel and pack hard; the sand being more the same size particle, doesn't offer easy pathways for the earth, clay or mud to move into and pack and so the boundary remains relatively free flowing.

Kieran: > crawlspace

Crawl spaces were made to raise the house above the ground to avoid water. They do that pretty well. Good ventilation down there was always the plan. Ducts and plumbing were something added by HVAC contractors who saw a quick 'n' easy go of it. You may want to consider just ventilating well, removing sheet metal ducts and fixing any insulation (above the crawl) and installing permeable sheathing on the bottom of your floor just to prevent wind washing and keep pests out. Screen the vent openings securely. Grade or drain the site around the house as needed so you don't direct surface water under the house and unless you have a spring under there you should have a happy home. If there is wet insulation there it's most likely because you have a leak above it. Putting linoleum (a natural product) on kitchen and bath floor just make sense compared to any kind of wood finish floor.. Keep the tub surround and shower walls and pan properly caulked and maintained; caulk around the bottom of the tub and toilet.

Not much magic here. <g>

Rufus

I have to be honest, the reason I was attracted to this book is the MGO content. I am struggling with building codes, banks, appraisers, insurance and real-estate agents, developers, sub-divisions, getting rammed earth, strawbale, hemprete, approved to where I as a natural builder do not take a loss. I talked to George on the phone, he has done all that and much more in Austin, TX, and since came up with methods (mag boards, low density fiber board made of petrified-clay mineralized wood, and Portland cement in the form of ICF’s) that are easier to adapt to this mainstream conventional mess we are in and I want no part of. Yes, they are industrialized but it is a start getting over the hurdles. If you are in a rural community and plan on never selling your house and having to worry about an appraiser or buyer’s bank that can’t get their head around the value of natural materials that are better for our health and environment, then you have nothing to worry about. Unfortunately, these hurdles have stopped permies and natural builder dreams, some get us far along in design only to find out about these road blocks. Some are good for public safety, since some do not understand a lot about mold, materials, and how they can harm health and structure. Then again, today's building codes and Architects are not much better and with all the sealing going on it is getting worse. So the book both promotes natural building materials some not much that are also manufactured using more natural materiasl that have less environmental impacts and embodied energy.

Kieran: Here is how I developed that mix. I started with Type S lime in a mortar applicator along a stud-sheathing seam (I figured the MGO content was enough of a binder), it cracked. I added 1:1 fly ash, it still cracked. I tried Portland cement with fly ash since I read it makes it stronger, it cracked. I added a little straw, no cracks. Final, binder: Type S and Flyash, 1:1..water in bucket first, add binder and mix, add straw 20-30% or until my drill paddle will not turn anymore. Cellulose (straw, wood chip, etc) petrified in clay or any binder like this is protection from fungi. The straw promotes capillary drainage and insulates, and keeps the binder together in tension. This composite is air entrained by the mixing process with open pores that wick and evaporate, not condense. Spray that water proofer on the wood first and after. The clay will neutralize the wood sugars, this is how below grade cellulose fiber board that has been around since the 19th century works, it started in Europe now is in the US. The Portland cement provides an alkaline surface that prevents mold. The troweled surface will close the upper pore rendering it “plastic” like but still leave permeable. You could burnishing the horizontal planes as Bill does on lime plaster with a trowel to close the surface pores more. Test a section until you see some beads. Or angle them so the drain from gravity. I am assuming you do not have a neoprene or peel-n-stick capillary break between the concrete and sill. If not that could identify the issue, especially in MI. I was there working last year in winter-spring-summer , 100 miles east of Detroit, and it gets moist there. That mix might offer a patch job break, or, getting heat to the CS may be all that is needed to stop condensation on the rim. But this would also seal in heat in winter, so it may be good to use it to seal vs toxic spray foam. There is probably no access but you also with the use of forms produce an insulation cast in place block.

I know OPC (Portland cement) is not desired since it produces twice as much CO2 that is not reabsorbed like lime (calcium or even better magnesium carbonate), but if you have to haul in bags and pay for shipping what is the point. Here they have cheap bags of lime and “Sutherlands” bags of fly-ash for around $10/80-90 lb bag. Portland cement is cheap we know that is why it is so popular with all its issues. Good news is mag is making a comeback. In the meantime, we have to use what is locally available and bags of MGO are not readily available, other than Type S has some which is fine. I’m not sure it that will work with that bentonite water proofer. Pure “light burnt” MGO can be purchased here: http://www.premiermagnesia.com/cpg/magnesium-cements.

Or here: http://www.rosendalecement.net/html/rosendale_natural_cement_produ.html

And here are some coating products that breath, Silox is one, there are test above using silane-siloxane water repellents, they are affective as noted, you can use on both sides of the wall.

http://www.edisoncoatings.com/store/sealers-consolidants.html

Tec-eco in Austrailia.

China has a lot of MGO but you have to watch quality. George can help he has been over there many times. He can also get mag board or it is all over the internet,

Here are a couple of suppliers that have code approval or third party testing: http://mgoboard.com.au/
http://magnumbp.com/products/mb-faqs.htm

If I were to sheath an existing crawl space ceiling-floor, since it is too late to drop in a limecrete on battens, I’d use mag board or a products like Durisol or Faswall even if I have to ship them is as opposed to OSB and plywood with all their clues and resigns that are food for mold. Drywall paper, linoleum glues, calks, sealants, most glues are usually the food source. The glues break down from thermal and structural fatigue cycles unlike natural cements do not in nature, let moisture in the voids, grow mold, or suffocate the interface trapping moisture in if it does get in which is inevitable.

As we have seen from Bill that opens walls up tearing latex paint down to the gypsum to expose a hygroscopic materials to interior air, the same will occur from the boards noted above that the typical OSB, plywood, paper faced drywall, will not have as much of to absorb/desorb to the surrounding moisture in the area. MGO, lime also absorbs C02 faster than Portland cements.

Kieran bathroom remodel has so much hygroscopic mass the wood will be fine as Bill has proven in many builds, and history has shown. A wood floor in such an environment that is able to dry in a 48 hour period would do fine as well. Not the case if you vapor lock the room with plastic or glue barriers that stop hygroscopic intake/exhaust, or that do not transfer heat through them to dry vapor, creating a condensing surface and high temp dew point.

Chapter 12.4 “The physics of vapor pressure and migration” explains the elevated temperature to soil ratio. It assumes your walls can breathe to the outside, but also states that pressure should be enough to push vapor through any material.

Eight feet of soil can exert quite a force on tiles and rocks and fatigue over time, especially from high expansion soils and tiles that are not draining properly, freeze thaw cycles, etc…The average force is said to be 1800 lbs-ft2 at 8’, the greatest crushing force is the resultant of the vertical and horizontal forces or “killer load” (like pushing a lawn mower down and and forward) the book refers to in the foundation section. It is common for homes to have drainage issues to day light and that may be what is happening with Kieran’s, in part or whole...check your drain output when it rains. We did not know as much 60-80 years ago as we do now.

The sand back-fill makes void and even load distribution sense, since without air drainage cannot occur or hydrostatically locks. There are membranes available now with dimples that have air gaps that are uniform unlike pea gravel. Studies have shown with uniform gaps drainage is faster…makes sense to me anyway, more than flat mastic's used as a water profer that do not drain well or pull moisture of the concrete from vents. Delta MS is discussed in depth. There are also mineral wool fibers rated for below grade that drain well, but have little MC ability.

I did not get into that with you Kieran because I assumed you have good hats and feet, and do not want to dig out your foundation walls and redo them we hope is not the case.

As far as the radiant floor heat and getting down to the CS….We know heat rises and yet moves from hot to cold so it may work. We see above that the human body does not need as much radiant heat (12 F) less to get the same comfort level as forced air. The idea looks interesting if you can get it past the fire marshal. Some are going with ceiling installations I don’t understand how they are as effective unless in mass. This book promotes the use of thick wall mass or thin wall using fiber-cement or magnesium, not little mass and high insulation. Mass can be just as insulating if you understand it, it does so very differently from low mass/high insulation.

Rufus: Thanks for the input I address some of it above. The only place the author’s and I’ll add myself would disagree is with the use of low hygroscopic materials like linoleum. There are “natural” materials that are glued together with non-natural food for fungi. If the binder, some noted above, are inert and that can be viewed in the spec or MSDS ok, rarely the case. Wood, lime, MGO, clay plasters, and natural ventilation and methods that work with the forces of nature not against them are the focus of this book. Caulks, peel and sticks, petro-based water proofing membranes, have their limited place as long as they do not trap moisture/air flow, and provide food for fungi in the same camping grounds

Thanks for the inputs guy’s, outside of Bill I was feeling lonely, there is little interest and I was posting to myself. Ask for opinions without data we see plenty, ask to look at data we get little, go figure! Don’t worry about hi-jacking the thread, keep it coming it helps me understand better when I have to go find answers and put them to practical applications. This book has drastically changed the way I was taught by reading to many opinions on mainstream sites. I get kicked off them now for proving them wrong like the book does and ruining sales/sponsors, challenging “building Scientist”….Not that I know it all, but neither do some of these guys clearly or they choose to ignore the data above.

Here is Kieran’s bath remodel thread, surface treated wood as an integral part of the surround hygroscopic mass. Most would not do this but I believe the wood will never saturate or get past 28% EMC after a shower or if you put water on the surface being crossed grained.
https://permies.com/t/43317/natural-building/Bathroom-Remodel-Retrofitting-Natural-Materials

I agree not much new magic just a loss of the magicians that made it happen prior to the industrial revolution, now the "green" washed revolution is thinking they are re-inventing the wheel with the same materials doing thier best to get the toxins and mold out of the assembly lines, Energy cost and CO2 levels down to stop global warming, etc, and at the same time sealing it up to get to Germany's "passive house standards" when Germany understands the material science way better then they average USA builder designing homes. Now anyone can get on the internet become a building historian or architect, some popular sites like GBA ("Green Building Advisors) are charging for the green washed knowledge to pay the sites bills. GBA is very entertaining, they put a straw or earth build up once in a while to look natural, then never recommend their use in their Q&A section. That brings me here. It's a shame since there is some talent out there either unaware or ignoring this stuff.

Forgot to mention, 2008 is the latest and only addition. Well worth the small price, the knowledge alone...I'm sure there has been growth in materials not noted in the book like MGO board, etc, since. They refer to it as a building "manual" not book. I'd agree this one goes with me to job sites, books stay home on the shelf.

Great to hear all of that Terry. Many things to take into account, and I really enjoyed reading your thought process as you experimented with the limecrete. I hope to be able to work through something similar. I'll look into getting a copy of the book sometime soon.

Hi Terry,
Great stuff as always!
I'd like to point out to folks that they should scour/compress any natural plaster or air seal/filler type material when they start to dry and crack. Lime is self healing so the cracks will just heal up and go away. There are many pozzolans, fly ash from coal fired plants is not one that I use. Easier and usually accessible are; volcanic tuff, pumice or ash, diatomaceous earth, burnt clays, ground brick, calcined basalt or bauxite, wood ash, and really anything with a silica content of 40-60%.
Always add fiber to your mix as well; straw, hair, plane shavings and manure are easily obtained. The fiber absorbs water and slows internal drying which helps prevent cracking. Fibers also reinforce small cracks so they don't spread.
Crawl space treatments vary so much with climate and design that I would have a hard time really recommending a solution, but this sounds like a good starting point. Observance is always your best bet.

I have been lime plastering on drywall and thought I would share some images of breathable walls using drywall. It is interesting that the unfinished drywall does not readily absorb water. When I sprayed the bare drywall board, the water ran down all the way to the floor, but the same spray on drywall with a single coat of lime plaster absorbed every bit.

The third photo is of the back side of the plastered drywall. We spray the walls with gallons of water in order to ensure proper set. You can see this water diffusing through the gypsum and wetting the paper on the backside of the wall. The plaster side looks dry.

Bill, when you say "Bare" front side you took the paper off? And then put lime plaster on?

Check out the new buzz word Phase Change Materials (PCM)s that add a coat of paraffin wax on gypsum board and patented it:


http://www.zdnet.com/article/game-changer-phase-change-products-boost-building-performance/

http://www.psfk.com/2012/08/wax-drywall-reduces-energy.html

I use to use that wax on my surf board. Never thought it be on walls. Perhaps we can go surfing?

Hi Terry,

Interesting stuff with PCMs in drywall. For me, I wonder if you can plaster directly to the paraffin enhanced drywall, if a sanded primer will be necessary or if they plan on developing a paraffin plaster and would this still be breathable?

In my photos above, the piece of drywall is bare; we stripped the outer layer of paper from the wall behind it since it was painted with latex, but the walls with new drywall perform exactly the same as the one in the photo. My thought is the paper is not very porous, so doesn't absorb water quickly, but once impregnated with plaster, moisture can travel right through. This can cause a problem with drywall and insulation over 3 wythe brick, creating a possible condensing plane, so I use the blue paper to restrict vapor transmission in the winter, but allow full permeability in all other seasons.

This is my thread on plastering drywall https://permies.com/t/46164/Finishes/Converting-latex-painted-drywall-lime

http://www.greenbuildingadvisor.com/community/forum/general-questions/36320/installed-r-60-insulation-attic-now-using-ac-more

I don't know if you guys seen this one where the homeowner went from R-11 to R-60, air sealed, the attic and home is still performing poorly or worse. NG at the bottom just did a very good thermodynamics breakdown of the radiant heat gradient that is in part the problem, air sealing will not solve since air does not hold much heat as he said. Had the house had more mass a better transport/storage system of radiant heat then drywall (glued paper faced gypsum) it could manage the heat and realtive humidly better instead of the HVAC, as well as the time lag to night time cooling. He fails to factor in the low hygroscopic properties of the material coupled to the interior conditions, popular drywall. If he ripped out all the paper to just expose the natural gympsum and plastered an earth and lime plaster on all interior surfaces like Bill does the problem would be solved. If this house had 2-4" of traditional earth or lime plaster it would not have these issues.The only cooling climates this performs poorly in or fails are high night time heat-relative humidity above desired set points what are rare (this is not one of those cases). He'd drop is cooling and heating loads by far, especially if he combined this mass with the sun and night time radiant cooling. Bill does this for a living....countless cases of insulated or non low mass interiors that under-performed until large interior hygroscopic internal mass was added. The same type of mass to the exterior can keep heat and humidity out of the attic, function to pull humidity and radiate heat out in direction through the ceiling, along with air vents that are not really that effective and drawing radiant heat out of insulation. Radiation seeks cooler radiant surfaces, humidity seeks lower too, air affects both very little hence the higher ventilation rates under performed.

Interesting though how people dump huge money into homes just to get poor results. If they had just purchased that meter and got some data first, or hired someone that knows what they are doing.

This could probably help more than an air barrier: http://www.radiosity.biz/Attic.html

Hi Terry Lee,

That would be funny if it weren't so tragic. Those dogs were just chasing their own tails and when you tried to influence the direction of the dialogue, they either chased you away or ignored your excellent advice completely.

Through air sealing and insulating, they have achieved a fart filled box where humidity and CO2 can only be lowered by running the A/C and opening windows. I tried to log in on GBA, where I was a member nearly a decade ago in my previous life as a home performance contractor, but I guess I'm no longer a member.

I would have posted that I could cure the home of the high humidity and CO2 plus reduce the A/C usage for about $5/sq ft of wall and ceiling area. These esteemed gentleman(this is how I politely say puffed up hypocrite) can't seem to see past their own rhetoric and dogma. There was not a mention of latent heat of vaporization and the way this heat source has been manipulated by our ancestors for millennia without resorting to the fart filled box. It is a sad commentary on contemporary society that a group of supposedly forward thinkers could be regurgitating lies promulgated by the corporate disinformation machine and disseminating them as cutting edge technology for the benefit of all humanity.

Keep on keeping it real!
Bill

Well Bill, I decided yesterday to take down my identifying info off JLC after telling many how bad the majority of advice was out there is including from the MOD Chad Fabrey in a “Building Science” section that is anything but that, and I don’t learn anything from anymore. I started there in mainstream, then had to undo most of what I learned. The latest debate I disagreed with putting a foam vapor barrier over “air sealed” bays with pine T&G attic floor that had a ceiling vapor barrier below and fiberglass insulation that would trap moisture. Foam on hygroscopic wood that pulls moisture out of the vented airstream and insulation how crazy is that? The only way to be on foamaholic and plastic solution sites like these as a natural builder is anonymous, you get attacked if you point to natural material data that is in this thread. This is the only site I feel safe revealing myself and my company info on. You are not missing anything by not having accounts on these sites, I won’t post on GBA or JLC anymore. They are good for cases like this to learn what not to do. The sad part is people that go to sites like these get mislead, and little changes in America one of the worse building communities in the world for the price paid. Hopefully we can change that out here.

That thread is VERY entertaining. With the latest additions it is getting close to 50 unfounded opinions that point to no creditable material properties that were developed by labs, field testing, and massive history in this thread. Typically, in most professional environments I have been in many, if this was present in one, the first order of business would be to develop data points over a 48 hour period that includes several relative humidity reading’s from a psychrometer mulit-meter to determine RH gradients, temp gradients, reading’s at different locations inside the attic, insulation, indoors, outdoors, air speeds, pressure gradients, etc, and also to monitor fungi growth since that is the biggest reason we control moisture and temperature in these assemblies that rarely gets discussed….The process is called “cause and corrective action”. Data is developed and reviewed before corrective action. Pretty much what I posted early on “we simply do not have all the facts” ….but people love to give opinions and their personal unrelated experiences, so we got just that, many, and I doubt they stop anytime soon perhaps it hits 100? Now that would be funny! I did not have as much data back then to point to, and I even made some errors in my statements I see now with regard to relative humidity as the primary source of vapor drive, as there are MANY from others on that thread. The majority as seen alone by the lack of discussion on the three vapor transport systems in this thread and how they affect heat drive. That dynamic is actually very complex if you get right down to it, no math equations are going to define and solve. A better tool would be a calibrated model to the specific climate zone like WUFI as a start but it would correct input data.

The classic was Martin’s response to my suggesting the use of more proven hygroscopic thermal mass like clay and lime, in most cases they are a “no brainer” solution just based on properties above that remove opinions from the equation.
.

Jeff,
Terry's opinion that "the best way to remedy your issue is to add mass" is not universally shared. In most homes, adding thermal mass costs so much money that you are unlikely to see any payback from the investment. Improved airtightness, high-quality insulation, are proven approaches.

Absolutely chasing his own tail and contradicting himself which he does often since he completely misunderstood that there is insulation in all mass that although may have a bench tested lower “industry unacceptable “r-value” out performs in sustaining r-value when it gets wet (such as binded clay/lime/hemp/flax/slip) and works under a completely different dynamic mechanism and benefit than say fiberglass batts or cellulose surrounded by sheathing and drywall, vapor retarders and barriers, etc. The binders in these insulating masses creates an air seal by default and I am not saying that keeping conditioned air from escaping the envelope is not needed but, they are better than the caulks on the market that fail hair-line cracks from movements and poor sustainable bonds, then trap moisture behind those cracks than produce mold since they are not inert materials. They are better at eliminating or reducing moist air loops and barriers in bays that lower r-values in batts. These “25 year” caulks if thermally cycled will see a life of less than 10 years, polymer sill seals the same. I have tested many in professional labs to determine cause and corrective actions. As I said, like apples and oranges, high r-value insulation assembly designs and mass. Mass also has other benefits like sound reduction that need special batts for, CO2 absorption/desorption, etc, noted above….The data is above that includes charted, tabulated, vapor transports and gradients that need no barriers or retarders, layers, etc often yielding lower cost solutions despite Martin’s opinions….clear as day and it is not “universally shared” it is better than that it is “globally” shared except here in America, look at Germany that many look to for blower door test and pasivhaus designs but ignore that abundance of natural material data they use to get there. Here we totally misunderstand the use of the blower door test, air sealing, and “breathable walls” There are Germans that have .6 ACH @ 50 pascal or below and breathable walls.

The properties of the materials do not change because someone misplaced them in the wrong environment or has a lack knowledge of them and how to assemble them.

I wish I had the data George has presented in this book back then, it would have been posted all over that thread nothing but tables, graphs, little words. He set out to prove how current practices will cause issues like this and he did just that with facts. If you look at the thread you see the lack of graphs, charts, tables, you do however find plenty of worthless words and theories to solve the OPs issues that probably left the guy completely unresolved and more confused. Often sites like this twist the facts or misinform like with vermiculite insulation you straightened out Bill. You therefore end up with a site to promote mass confusion and product sponsors with enough unfounded opinions to make your head spin. Put facts out there and Bill, you and I for the most part are the only ones looking at and interpreting them, well George and his network too. Your experience provides more real world evidence of the data.

“Ignored” you’re are absolutely correct, I was and it was and from “Experts” that have been in this industry for decades, that are unaware? I doubt it, much of the data comes from guys like George and John Straube that also have been around the world showing this data to many, to include whom this site GBA gets some of its “selective” data from. Another person that got asked to stop posting and proving the data wrong on that GBA was a guy named "Richard" a product health expert they did not want to hear it from. What I find of more interest is even some when you present the facts from high dollar studies some still value their unfounded opinions more, or twist the facts. That is when I stop responding and wasting time. It never fly in a professional engineering environment I have spent a lot of time and therefore have not watched this industry as long as some, you’d probably get fired for even suggesting it.

Then what gets me the most is utility bills are the determining metric and only data if you did well? I fail to understand how it and ventilation rates determine or manage IAQ, VOC’s, toxins, how much mold and mildew is being generated from the junk in the products that were installed. I guess to some low utility bills are going to save your lungs and stop cancer. “Must be that “payback on investment” Martin referred to? If were going to that and not use our brain as a thermometer lets include the difference in set back between air and radiant heat on the order of 6-8 F lower or higher, more comfort from radiant walls, floors, and ceiling's that distribute heat-cold more evenly than nasty dirty inefficient ducts.

When it comes to “mass” the only thing the mainstream industry refers to is OPC concrete one of the worst performers out there, it holds on to moisture, dry’s slow, has a history of issues that needs all kinds of remediates like liquid toxic popular bitumen membranes, ad-mixes, foam, plastics, to attempt to solve but, in most cases make matters worse. How long has this product been in a R$D phase now? In a professional environment it should walk on water now after all the $ this industry has spent. Again, look at the data of it say compared to other types of cements or binders like lime and clay or MGO above. I did not disclose all what is in George’s book out of respect. OPC is cheap that is why it is still alive, I guess some have not heard of “you get what you pay for”.

Stay tuned on the thread Bill I think Dana is going to pull some more numbers out of his hat, fancy words and writing, worthless calculations without having the necessary instrumented data points I mentioned above. Well just call his “Dana Points”, what I’d like to see is for him to fund his theories and hold himself liable to the OP vs computer jockey design. Put his company name and website out there or some of his proven designs. I think the only build Martin did was his own home decades ago. This is going to be real fun to watch far better than cable TV. The guy does have an excellent ability to write, so does Martin, I call “the dynamic duo” I give them that but that is about where it ends. Thanks George for some real usable facts unfortunately that masses do not understand or ignore.

Well Terry,
I understand your frustrations with these types, but we must press on and inform the public of other options. We Permies types are a rare breed these days, but that just makes us more vociferous!

I am not a computer lover and I don't like teaching people who aren't right in front of me, but the amount of opposition to natural/traditional building methods requires that we put our best foot forward and teach these enduring principles that have been passed down generationally for time immemorial.

I agree with your decision to not fight on their home turf with those that have a vested interest in their own re-invention of sound building practices. We have a home here on Permies, where those that need advice are open to and agree with natural building philosophy. This makes it much easier to argue a point in the interest of Earth care, people care and future care.

Thank you Terry for your beneficial presence here on the only website I've ever felt comfortable posting on.

All Blessings,
Bill

Thanks for the encouragement Bill. Just got off the phone with George. My son and I are heading over 500 miles to see him and his builds. We had a good laugh about all the mainstream bandages and layers. He just got back from spending a month in China last night. He said they are light years ahead of us in building science. The best news we want from him is not getting to far out in left field that our trades, inspectors, banks and appraisers, real-estate agents, don't understand.

I should be threading a build soon. We decided to start residential go from there. We're going to change things up and hope to keep doing it.

Is there anything in the book about what to do if you've built NOT using these principles, and now want to make what you have more breathable?  

If not in the book,  can someone point me in the direction of who to consult for this very thing.  We built brand new construction 5 years ago.  I knew about breathable walls, could not afford the extra that Durisol was going to be, went typical modern american construction.  Guess what we are now having a few issues I'd like to see what my options are to help my situation.

Hi, I know this is an old topic. I am building a house with adobes in Cyprus. It is based on a steel frame. We left a 10cm gap between the exterior adobe wall and did a steel stud wall and placed cement board. We where told to then drill a few vent holes on the exterior. I am not an expert so I don't know how many holes will do.I have been told not to use cement based plasters on the interior as cement does not breath and create problems to the earth wall.. We have a special gypsum+perlite mix that they use for earth walls. However these are relatively soft and I am afraid that walls will be banged all the time by the kids. We even thought of doing the same as we did outside, creating a steel stud wall and placing either cement board or gypsum drywall and again create vent holes. however its not as solid as a cement plaster on a reinforced adobe wall with mesh. any advice will do.

Hi everyone,longtime lurker, first post.
I have yet to see any mention of expanded cork panels in a thread. Carbon negative, r-4/inch, exterior grade, vapor permeable, bug-proof...Why not? Well, they're expensive, though (in my opinion) not prohibitively so. I'm designing a tiny timber framed home wrapped in cork. Any thoughts?

hy,

If possible, it will be greatfull to have your hint for our construction.

We build a straw ball house in Quebec, Canada.

We already do the COB on the two side. It's a 2 inches of COB : sand, clay, straw and horse manure.

On the inside, we close the grain so the coat is smooth.
On the outside, we let the grain open and we do some keying for the last coat.

We will do 2 coats of lime for the exterior (around 1/4 inch for the both coats). We will put some casein, methycelullose and brick in powder.
We really like the aspect of the interior and if possible, we will keep it like that.

We are not sure if it will be okay for the moisture, because the exterior plaster will be a little less permeable than the interior because of the 2 coats of lime.

Because we read that
In cold climates, the trick here is  to design the wall so that the exterior is at least as vapor permeable, and ideally more so, than the interior.

Do you have any clue?

Is it okay to do that?
Or, do we have to do also a lime coat inside? or a lime paint?
Or to put several coat of oil?
Or to put bee wax?

Thanks

Ianis