Raised Earth Foundations

While playing hooky from other duties I found this book (in English!) that may explain much of what Jay referenced in Kanji.

Traditional Japanese Architecture: An Exploration of Elements and Forms
By Mira Locher

Google books sample link:

http://books.google.com/books?id=njnRAgAAQBAJ&pg=PT266&lpg=PT266&dq=hazama-ishi&source=bl&ots=jlWa95aOCf&sig=Rz-6WTIrtevIfY0LJhRd_Pr6i7w&hl=en&sa=X&ei=4lyvU7yuC8yWqAbUt4GwAw&ved=0CCIQ6AEwBA#v=onepage&q=hazama-ishi&f=false

Good find Rufus. This will be added to my wishlist and purchased soon. It looks like it has detailed explanations about the Japanese buildings, as opposed to many books that are simply filled with pretty pictures.

I wonder if there are any websites/books that detail raised earth foundation processes: layout, tools used, local materials that can be scavenged, etc.

Thanks Rufus, for sharing this title, a good book especially if you are student of Asian architecture, and another fine example from Tuttle Press, in there long line of Japanese architecture books. I got to read a "before release" editorial copy, and though I found it a charming book with beautiful photos seldom shown in books in English, I don't typically recommend it to students....Why?

The simple fact, as for most of these types of "coffee table" books:

1. It is still written by someone that does not actually "do the work," they only photograph the work of others and then describe it, albeit in fine detail.

2. This is still not a "technical manual" of any type.

3. This is the main reason...money is tight!...Now the book can be bought for as little as $25 dollars (half the original price) yet all the information in this book (90%) is on the Jaanus web site.


The authors do a wonderful job of framing many of the points reader know me for droning on about, and the photos are wonderful. So, for $25 you won't regret owning it...but the info can be had on the "net" for free.

Please do keep looking into these publications...there are quite a few very good ones, but of course the best are in the original language.

Regards,

j

Thanks Jay,

Sounds like I should see if I can find it at the local library instead. I have enough books to purchase as it is.

If you were to recommend a replacement book for Asian architecture "know-how", what would you suggest? Or is there such a book in print currently (in English)?

I wish was such a book..(or maybe not?) ...and part of the reason I am trying to get my stuff together to write on or at least put the equivalence of a book here at Permies.com. There just isn't anything really up to date in the timber framing-natural building field that isn't saturated in both the "european mindset" and/or still heavily "into" modern means, methods, and materials.

I have several "author friends" including one that is about to publish a comprehensive book in English on Japanese Boat building...Even he has said you don't make any money at it, but on the back side doing classes and lectures about the subject. So I would rather just see folks have the info, and when I teach they can front load themselves with the foundational knowledge.

Actually most of it is out there now...its just not in one spot, sorted, and explained well to "first time" builders and those that have never worked in "Eastern Methods" of construction.

Regards,

j

Jay

People source:

I took a joinery course with Paul Disco long time back. He went to Japan in the 70s and studied temple building under a Japanese builder for several years. Seemed to know his stuff and loved the "old ways". The links below is the closest I came searching the internet; he's likely living in Berkeley but equally might not use the net much/at all so it may be a bit of a job finding him long distance. Guess he's in his 70s now. Maybe keep an eye out for him. He might be a good hands on source for traditional building and might be an aid in putting some of it down on paper. Maybe. He tended to talk w/his craft. I think I saw he was working on Larry Ellisons's opus magnus house, probably making furniture or wood art but don't know what time period that was. If you would really like to find him I can probably go and dig around the SF craft and Zen community; shouldn't take much as he was/is well regarded in those circles. Be a while though as I'm in Chicago now. If you know people around SF you can probably find him.

http://www.fouladiprojects.com/fp/ArtistDetail.jsp?id=20577

http://hyperlocavore.ning.com/forum/topics/from-saw-to-table


Rufus

Hello Rufus,

Thank you for the thought...

I have known Paul D. for over 30 years and have met several times. He did have involvement in the Woodside California residence of Larry Ellison...as did many of my friends and colleagues over the years of its construction. That project was a long and "bitter sweet," task for many in the Asian woodworking field. As far as I know he is very involved with his children, Zen practice, and his publishing with very talented daughter. His business "Joinery Structures" is still going strong as far as I know. He is on par with Len Brackett, also in California...which has a concentration of Japanese/American woodworkers and Timberwrights. Thanks for sharing his name here, though his style is more "imperial class" and not the "folk styles" I tend to specialize in. Anyone would be lucky to study with him should they get a chance.

Regards,

j

I would like to thank you all for this amazingly interesting and informative conversation. I won't go into details, but when I began to think about building my own home, I really didn't come to a satisfactory solution for a foundation. So I could almost call this thread inspiring.

One question I must ask is how these types of structures would perform in areas with lots of frost heaving?

I've been following this thread assiduously, as I feel it's one of the most important parts of "permie building".

I love J.C.W's philosophy of looking to centuries of "tried and true" ancestral and vernacular methods before considering the mere decades-old engineered solutions for problems. I keep telling people that science and engineering are two different disciplines-- and that part of the problem with the modern world is that we have rewarded engineering far more than science. Science is about understanding the world around us, while engineering is about changing it. If we apply a little more science to the question of understanding why vernacular ancestral methods worked for making snug, comfortable homes, instead of trying to engineer our way into doing the same with expensive and unsustainable modern materials, we begin to follow the spirit of Permaculture a lot better.

One of the most basic principles of Permaculture, emphasized in Toby Hemenway's book "Gaia's Garden" is the importance of water control. Water control can be about handling gray- and black- water in a sanitary and useful fashion. It can be about storing water for use in dry months, either in cisterns or delivering into the deep soil via swales, and getting precious water to plants in semi-arid or arid areas. However, it's also about keeping water away from places where it can be a problem.

I just found John Hait's book on PAHS on Scribd.com, and I was shocked and surprised when, as I was reading it, that he has a section on putting a vapor barrier around the walls, even going into detail about how to pleat the plastic vapor barrier material so that it doesn't stretch and break as you move your back-fill in. I was confused, because I thought that the whole point of the umbrella was to dry the soil beneath, keeping excess moisture off the walls/foundation and out of the living space. I still don't understand why Hait's method asks us to put vapor barrier up around our walls. PAHS essentially gives us 20 foot thick "walls" under very, very deep "eaves" of a living roof. Yes, those walls are faced with whatever we build immediately around our living space, but the soil out to the 20 foot mark is every bit as much a part of our "wall system". Ideally, it ends up as dry, compacted soil. Moisture migration through that soil should be minimal if we channel and drain away the precipitation moisture effectively.

"Rising damp" is addressed in his book when he recommends drain tile below the footings, so that groundwater doesn't end up in our floor. The Japanese methods Jay has brought our attention do bring even more attention to that, creating a sub-floor drain to clear any moisture away. So long as we are building well above the water-table, we should be fine. Even if the water-table rises, if we have any slope at all, we can drain water away to daylight.

Anyway, I found these images interesting:

Orkney Island Preshistoric Village

This stone-age culture built homes in one of the harshest, wet and cold environments you can imagine, but they were likely fairly snug. We don't know exactly how they roofed these structures, but rough-dressed sandstone walls, bermed with earth (actually, they built on a midden, and bermed with the same). How they kept them dry, I don't know, but I'd love to find out!

George Spencer wrote:One question I must ask is how these types of structures would perform in areas with lots of frost heaving?

Hi George,

Well I can tell you that "rafting" is how they build in the Arctic circle over "permafrost. These traditionally had been done with a grid of timber and earth, sometimes stone and this is still done today. A more "modern" interpretation is done with gravel layers and "geo cloth"...I find both system applicable.

As for how this works in areas of "frost heaving," I say better than just about anything you can pick from in modern times. For "heaving" to take place there must be accumulated water and soils to support the matrix...with this method...there are none. I would also point out that soil type is just (if not more) germane to frost heave than water...as the "clays" in the soil is what is really contributing to the "heaving" effect...not the freezing. Bentonite clays expand way worse than ice formation...and combining the two is horrific. However, remove, and pack in stone, and even these clays are rendered harmless when managed traditionally with systems like raised earth foundations

Hello Kevin,

Thanks for such a gracious post. There is so much in it I could respond to that I would begin one of my "babbling rants." Would you like a response to anything specific? Thanks for sharing your views on this. as you have noted living with gravel foundations has been around for a long time...as has the entire concept of PAHS has been...Then again, I see little that our wise ancestors have not already done...often much better than we are doing.

Regards to all,

j

Thank you so much Jay for your post, there is information about natural building here that I have found nowhere else.
We are shortly to begin a cob/balecob structure on a 5 acre block gifted to us by friends - as the owners of the land are living in a shed on it elsewhere, there is no possibility of us making this a legal build. With that in mind I feel the opportunity to reject modern materials is too good to pass up. However, finding information on HOW to not use concrete and plastic is next to impossible. Not to mention full of dire warnings of catastrophic failure if you do not!
We are building load bearing cob with an earthen floor. How do we build an earthen floor without the ubiquitous plastic barrier? The same as previously stated; packed stones? Also, is that what we should use for the wall above the foundations and below the cob? I would like to avoid concrete mortar. Is cob suitable for the mortar in the stone foundations?
I apologise for so many questions. I have followed all your links and was tickled pink by the use of mortice and tenon on the rock and timber foundation stones. I'm an avid fan of it in timber, would never have occurred to me to use it with wood and stone!
Adrienne

Dear Adrienne,

I would suggest that you start your own thread to pose your questions. (If you need help doing that...just ask me or any other staff/steward and they will be more than glad to help.....) This way you can reference it as "your own project," for information specific to what you want to achieve. I also thank you for your kind words, and IT IS part of the reason I write here...which is...to coalesce all the things I have learn over the decades in one place so folks, like yourself, can come and learn, as well as, actively ask questions they may specifically have to a project. Certain "generic" questions...or challenges...I address here on this post thread. The collective Stewards, Staff, and general members here at Permies are a wealth of experience and information...Welcome to the group....

Here is the quick answers that I can expand on when your post thread is created...

How do we build an earthen floor without the ubiquitous plastic barrier?

Pretty much like I have described in this "Raised Earth Foundations," post thread. There are others of course and other forms. With photo and details of your land...I can get a wee bit more specific to perhaps help.

The same as previously stated; packed stones?

Yes...in many (most) building sites.

Also, is that what we should use for the wall above the foundations and below the cob?

Hmmm...perhaps, but I need to see photos and understand your architectural goals better...Your current thoughts may be better served with a different approach.

I would like to avoid concrete mortar. Is cob suitable for the mortar in the stone foundations?

Yes...and concrete...(or the majority of it)...can almost always be avoided in most architecture...even commercial if the social building culture would shift from I.R. Big Industry and back into Artisan/Craftsperson lead building practices.

Thanks Jay, I will do that - would the cob forum be the best place?
Adrienne

Yes, that would be a fine thing to do...Then, if need be, I or others will "link" your discussion to other germane groups here at Permise.

I was looking at those links, for example https://www.google.com/search?q=%E5%89%B2%E6%A0%97%E5%9C%B0%E6%A5%AD&qscrl=1&source=lnms&tbm=isch&sa=X&ei=cIyIU9bjB7HRsQTru4HYDw&ved=0CAgQ_AUoAQ&biw=1024&bih=548

Quite a few of the photos show the use of plastic...

Hello Paul,

I used that link to Google Images as an over view of the method. There are indeed “some” that show plastic.

I would also point out that the plastic in many of the photos is a there to keep the gravel in place during the construction process, so the stone does not get disturbed, not as a vapor barrier. Some will just use filter cloth between the different grades of stone in some builds that they leave in place after construction is complete.

After the foundation is complete, the plastic is removed on many of these builds. Understanding the complete process to this from of architecture is paramount to doing it correctly. It is difficult for anyone to obtain a complete understanding of how these systems work by just looking at pictures. After studying thousands and building several, I am just beginning to get a full understanding myself. I recommend anyone that would like to use these more traditional systems to ask for help from those that still build this way.

The primary point of this post is that vapor barriers are a “new concept” and not a requirement of good architecture by any means. From forensic work, it is not even clear just how well they work over time anyway, nor are they proving better than traditional systems…

Oh but contraire monfraire. Iam not aware of any forensic research that casts doubts on the usefulness of subslab vapor barriers but would be interested in reading them in anyone knows of any. Tough to know more about the subject or do more forensic research than the good Dr Joe of BSC. Ive never seen recommendations from him that exclude it in the appropriate locations. Not saying it cant be done (avoiding sub-grade vapor barriers) but most building codes require it and building experts recommend it.

http://www.buildingscience.com/documents/reports/rr-0206-foundations-moisture-resistant-construction

Unless your water table is higher than the slab, there is no reason for a sub-slab vapor barrier. If proper drainage is installed, then how is this vapor going to enter? I am sure there is a place where this is necessary, but nowhere that I have ever worked. Over the last 20 years, I have dealt with hundreds of foundations without a single one needing plastic.

Hello Brian, et al.

I am not, nor claim to be a geotechnical engineer, though I have worked with a few. I do have some spattering of knowledge and/or have read a thing or two about phase wetting imbibition, osmotic pressure effects; cohesive diffusion vs true capillarity, permeance, and other related points as they relate to stone, drainage, foundations and the like. I may even have a wee bit of experience as some of this may be germane to construction in general, and/or like trying to wrap me old brain around research and papers that find their way to my reading pile. I have even come across a few studies that are more an examination of vapor barrier applicability and effectiveness, well before the digital age. Often, as I find in many of the industry based means, methods and materials, be it food, fuel, construction or otherwise, there are agendas. (Even here, we have the agenda of natural and sustainable building with as little industry involvement as possible.) One has to ask, “who funds the research and what are the agendas?” I can say from 40 years of remodels…vapor barriers…very often…are not working as intended and/or not necessary. Not even the many industries themselves agree on this subject. For example: in 2001 the American Concrete Institute (ACI) recommended 100 mm of “granular fill” (sand) on top of a vapor barrier before a final foundation (usually slab.)…Now they don’t, and I am sure it will change again…Point is, the construction industry has been battling with its own systems of means, methods and materials since about the day they have found a way to profit from its manufacture and/or application…So for the sack of this forum…and discussion…let’s stick with “natural and traditional” systems and how they work.

I can share that just over the last few years in our work; we get to “undermine” slabs in the process of razing or remodeling. I always make an accreted effort to examine closely the condition of these “vapor barriers.” Yet have I found a single one in even average condition, in tacked, and not full of punctures and lacerations…effectively rendering them useless in my view, though some “experts” claim this has little impact even if 95% of it is punctured with holes. I have to question that logic, as if big holes, rips, tears and related compromises of the barrier don’t affect them…then why use them at all? That’s for another post topic…

I am a building expert, or at least some seem to find my views, experience and opinions in that realm, so there are some of us "alleged experts" that don’t recommend vapor barriers, and do not use them in most applications and/or as typically performed. I also work with many others that don’t care for vapor barriers, and the issues related to trying to use them (i.e. curling, cracking in the slab, ineffectiveness, cost, etc.) or just because “code” recommends or insists on something…does not…make it good practice.

Now before this conversation moves to far “left” I don’t care for OPC concrete in general, and this entire thread is dedicated to…TRADITIONAL RAISED EARTH FOUNDATIONS…not concrete slab construction and its many ills. So let’s stay on topic of the post discussion and questions about this very old, very well proven, very functional, and…still in use today system.

So…getting back on subject…

If one just does a little web research on “foundation preparation” (for any style foundation…slabs or otherwise) DRAINAGE is about the only thing anyone agrees on…The more the better, and the better done the better the build...This post thread is about one of those traditional systems and how they have worked for the last 4000 years…

I've been working on a natural design/build lately, so I actually got out my dusty copy of the 2009 IBC. I looked up the requirements for different foundations and each situation referenced was resting on a gravel trench. So, if the load is ultimately transferred to the required amount of gravel, then why require monolithic concrete reinforced with steel? The concrete will crack and the steel will rust, so how is this any better than the stone/clay/lime foundation that my little adobe rests on? Why do we continue to waste resources on things that really make no sense? This is in the front of my mind, because I got an e-mail last night from friends who live in a 15 year old home that is leaking water into the finished basement through a crack in the concrete foundation.
Bottom line, short term thinking has gotten us to a state of emergency with our current housing stock! I for one can't keep up with it.
So, let us all learn from those who built homes to last. If it's over 100 years old, there's probably some good lessons there!

I understand the intent and title of this thread and I want to learn more, specifically how water vapor from the ground is viewed or mitigated for. Echoing Paul's comment, in the Warigurichigyō 割栗地業 search link, which is the heart of the thread as you say, I counted around 40 pictures of plastic, around 20 of which were covered, being covered or unlikely to be removed which makes me wonder how many more were planning on adding the plastic and covering it. I also counted around 50 pictures of steel reinforcement, which implies concrete, or actual concrete. Judging from the stages of construction, it appears that many of the examples without concrete are possibly on their way to including it. Iam guessing those many examples from your link are in your view of this method done wrong?

We all agree that drainage is key. I think most who include these plastic vapor barriers recognize they can help drainage by creating a condensing surface for water vapor, which accumulates as bulk water and is redirected down. Place clear plastic over beds of well-drained gravel and it doesnt take long to see the water vapor accumulating into bulk water droplets. A visual example of bulk water droplets forming from accumulation of water vapor from the Warigurichigyō 割栗地業 search link:



Correct me if Iam wrong but I think this is a fair example of how this upward migrating water vapor and soil gases are dealt with traditionally (without vapor barriers), again from the link:



This shows what could be described as a structure on piers or what we in the west call a vented crawlspace. Sure, you dont need or want a vapor barrier when building on piers with clear separation from the ground. It seems to me that this is closer to a vented crawlspace, which can work great in certain climates (usually dry) but can create more problems than they solve for humid ones. Building codes require vapor barriers at the ground in vented crawlspaces and this is certainly a case to me (as most cases are) where its safer to follow code than ignore it. Am I correct that ventilation below the floor is how to deal with water vapor from the ground in these traditional systems?

Iam also curious why its ok to use geocloth which is made from plastic and has a shorter "proven history" than plastic vapor barriers. Thoughts?

Brian, I know Jay will answer your questions more fully, but I'll give it a go.

The main driving force for vapor is temperature differential causing heat to migrate, carrying vapor in the same direction, from warmer to coooler(not up, that's convection).

The other is more intuitive; moisture travels from wet to dry.

The foundation wall is almost always warmer than the earth that surrounds it, therefor moisture is migrating out of the foundation wall into the earth unless it encounters a barrier. Then it will condense and saturate the foundation wall on the wrong side of the barrier!

There will be times when the ground is saturated, that moisture will travel against heat flow and migrate into the foundation wall, but this situation has it's own remedies.

The only time I see where a vapor retarder is beneficial is on the inside of an insulated basement wall, never on the outside of the foundation or slab and never a vapor barrier.

The photo you provided shows what would happen if you took soil and sealed it into a plastic baggie, then left it out in the sun. This doesn't really correlate to buildings though.

Lastly.... Thank you Brian for being the necessary counterpoint for a truly informative discussion.

Hey Bill,

I read your last post and gave it a thumbs up...then read it again and thought...well...short of just some editing (and me being to "wordy" sometime and wanting to expand things) your post deserved more than a thumbs up...so, an apple is in order in my view.

I too, appreciate having folks like Brian ask questions, yet sometimes it detracts from the body of the work on this forum. If anyone wants to build in more modern ways, by all means do so, yet I really don't want to get into what often seems like "defending a natural building process" over "using modern methods."

Architecture, and the design and building practices behind it, is as much sociological/psychological as it ever is..."good practice." It takes centuries if not millenia for actual "good practice" and common sense applications of them to reveal their applicability, true function, and understanding. This "chronological vetting out" of the sociological/psychological matrix of what so many..."think"...is a good idea, or must be done from what is actually necessary takes a long time. Most modern architecture, isn't even close to being around long enough to know what is...and is not...a good idea, or necessary.

I selected (perhaps I should not have) a very generic "image page" of Warigurichigyō 割栗地業 to show it. This page reflects a gambit of approaches and even some of the sociological impact of "the West" on the Japanese after WWII. I have been a student of many aspects of architecture, including the ethological impacts that take place. After world war two the body of the Japanese culture was internally stripped do to Western influence and the Japaneses own internal constructs within its society. Everything that was old (and/or often "Japanese") was consider "bad" or not of value. Entire villages started getting razed, and the Westerns left behind often subjected Western ethos, and concepts into the Japanese society. This influenced much of the rebuilding of major cities and it has taken decades for the Japanese to once again realize the applicability of their own building systems over what was forced on them. It also has take this long for many Westerns to realize their building modalities (or what they "thought was better") really do not work in a highly volatile tectonic region like the Ryukyu Archipelago.

...It seems to me that this is closer to a vented crawlspace, which can work great in certain climates (usually dry) but can create more problems than they solve for humid ones. Building codes require vapor barriers at the ground in vented crawlspaces and this is certainly a case to me (as most cases are) where its safer to follow code than ignore it. Am I correct that ventilation below the floor is how to deal with water vapor from the ground in these traditional systems?

Of all the things you could describe about Japan and the Ryukyu Arc in general...dry...is not one of them, and this presents as one of the reasons (beside tectonic instability) that "post and lintel" and/or "raised earth foundations" developed their superiority over other system in the course of several millenia of building. "Vented crawlspaces" are not only applicable in damp moist humid environments, they often dominate, and have little application or need in dry arid biomes...I am not sure why anyone would think the opposite as most "pole and stilt" architecture, with the clear airflow underneath is the dominant vernacular form in almost every tropical region of the world. So on that point, I would have to correct the assumption that "dry" locations are best suited for vented crawl spaces, it is usually the contrary, as the oldest and most enduring architecture in these arid regions are very often built as close to (or into) the landscape as possible, taking full effect of the earths natural thermal stability, because of, comparatively, the huge temperature swings between hot and cold that often take place in these regions. From North Americas south west to the Mongolian deserts these vernacular buildings are at grade or below grade in many examples.

Again, code is the least level to build to and has as much "bad practice" in it as it may have good, so I do not rely on it as a guide most of the time for my work, nor is it very applicable when trying to compare it to traditional vernacular systems. These systems have millenia of proof behind their applicability, functionality and really don't need to be compared (nor should be in most cases) to modern (very fallible) code systems.

Iam also curious why its ok to use geocloth which is made from plastic and has a shorter "proven history" than plastic vapor barriers. Thoughts?

I try, as do many perculturelist, to avoid modern materials wherever possible, unless it is a safe recycling of them. This is not to say there is a complete moratorium on them, as the many "hoop greenhouses" would suggest. Yet, wherever possible, it is done, and this is why "raised earth foundations" was offered as another example of building to mitigate their praxis. When executed properly these and many other building styles do not warrant or need a vapor barrier, and even in modern applications of them, in most cases they are simply not needed. I have, as I know others have, omitted them on all my builds and have not once in 40 plus years (when everything else is done properly in the way of drainage) ever had any moisture issues...at all...with their absence. This "vapor barrier" concept, again rose from what "seemed like" a good idea, into "it must be done this way;" in all a sociological gesticulation more than anything else as it just is not warranted and/or can be designed out of most builds.

As for "geo cloth" being new? I am not sure where that impression stems from? Geo cloth, in many different forms has been around for about 2000 years perhaps longer. Bamboo, reed and log matting has been employed as a geo stabilizer in several cultures, then before the turn of the century, textiles had been deployed to stabilize loose soil under road beds, and the practices just evolved from there. A geotextile or the equivalent has been around much longer than the aberrant "vapor barrier," practice with plastic. I would suggest in defense of the vapor barrier that the rammed clay in raised earth foundations could be looked at as a more applicable and germain "vapor barrier" yet again, this negates the need for the plastics.

I appreciate the thoughtful replies and I love the contrast between Bill and Jay's writings.

Bill, in your apple receiving post, you suggest that the main direction of vapor flow is from the inside to outside. For most locations, I believe the dominant direction of vapor flow is from the outside in.

Above grade, vapor can regularly travel in both directions. Underground things are different. Vapor is always trying to even itself out despite the temperature differences. I cant speak for the dry desert but most soils have moisture levels higher than what we want in our homes. The higher moisture levels of the ground will readily flow inwards towards a dry basement, slab or crawlspace despite any temperature differences.

My picture was not a plastic baggie of earth left in the sun. It's a picture of a building detail clearly showing underground moisture seeking equilibrium. This vapor is effectively being blocked and redirected to drainage.

Jay, are you suggesting that whenever you specify geocloth, you make it from "natural" materials? Most geocloth in use today is made from plastic and it has a shorter history than plastic vapor barriers. I think some thicknesses of geocloth probably use more of the earth's natural resources (plastic from oil) than these plastic vapor barriers.

I dont want this to come across as pushing modern methods over traditional. I think building on piers is the way to go if one is dead set on avoiding vapor barriers. As for underground walls and crawlspaces, Iam not at all convinced.. yet

For most locations, I believe the dominant direction of vapor flow is from the outside in.

Through walls, if not properly designed, I would agree...This is just not the case in the region of the foundational diaphragm of most structures and why the plastic can and should be omitted...if...all the other design criteria are facilitated and built properly.

Again, the plastic is not needed.

The higher moisture levels of the ground will readily flow inwards towards a dry basement, slab or crawlspace despite any temperature differences.

I can understand that perspective, yet Bill's points are valued as well. Temperature is the engine that drives moisture, and it has been my experience that moisture can be mitigated by this engine as well as venting and proper drainage. I not trying to guess at these conclusion, but do my best to speak from experience and observation of my own, others and what I can glean from the many tombs covering the subject. Temperature differentials are the primary "engine" in this equation, and there is very often, accept during certain transient times of the year when outside climate and inside are the same, in most architecture this very clear differential the rest of the year does exists, and clearly affects moisture movement more than any other factor.

This entire post acknowledges that most regions of the world will have a ground level moisture content of both free water and vapor greater than we want in the architecture.

Agreed.

You do not need plastic to mitigate this...not at all, and I have presented here just one example of natural and traditional building that proves this very effectively.

My picture was not a plastic baggie of earth left in the sun. It's a picture of a building detail clearly showing underground moisture seeking equilibrium. This vapor is effectively being blocked and redirected to drainage.

Unless you took the shot, and had been on sight during the construction process reflected in the photo (I have been on several of these that is why I selected the page), Bill's observation is just as valid and very accurate to what the photo depicts.

The moisture...by the way...could just as easily be from the concrete pore just so we are clear and a very heavy rain...NOT GROUND MOISTURE. I have seen it countless times and one of the reason many are omitting the plastic as it retards the natural drying that really does need to take effect during construction...Unless of course we are trying to slow the drying because...oh ya...because we used freaking concrete that is drying too fast and must be slowed down by wetting the foundation area.

Again, one mistake follows another...follows another...and the nasty cycle of "modern materials" not working in concert with each other and the biome it is built in.

Again...you don't need the concrete...you don't need the plastic...

Jay, are you suggesting that whenever you specify geocloth, you make it from "natural" materials?

No, not at all, I have and like to us only natural materials, but most of the road bed cloth I have "had to use" because it was spec'd by the PE or others is 80% post consumer recyclable material and/or felted carpet padding taken out of the waste stream...

Most geo cloth in use today is made from plastic and it has a shorter history than plastic vapor barriers.

Geo cloth is a concept that has been around for millenia. Between WWI and WWII it, along with many long chain polymer materials got all types of examination by the Pentagon and the petroleum industry.

So again, these cloths and the concept have been around as long as the concept of a plastic vapor barrier...

I think some thicknesses of geo cloth probably use more of the earth's natural resources (plastic from oil) than these plastic vapor barriers.

In pure volume I would agree, a geo cloth could use more plastic, yet more and more are moving towards post consumer recyclables. I don't care for the plastics...this is true...but my primary point is if they are not needed...why use them?

In closing...if you want to build modern...please, go for it, and make sure it is well design with all the technology it most definitely needs to operate well. I believe this can be done, as I have seen it done and we have members that have used foams, superinsulation and the related tools, I being one of them. If you want to embrace and take a more peaceful footprint on the planet try the natural and traditional modalities. They work just as well...perhaps even better...though I agree that is a subjective view.

Regards,

j

Take a clear piece of plastic and lay it on the ground, or even a thick, well drained layer of gravel. It doesnt take any concrete in the area to quickly get visual evidence of moisture in the ground, even if it hasnt rained for a very long time.

As to geocloth using more plastic than vapor barriers it appears I was even more correct than I originally assumed. I have some of the lightest variety (3-5oz) which I weighed at 1.6 grams for a 3" square. The 4 Mil plastic 3" square only weighed .8 grams. Not exactly definitive proof but pretty strong evidence especially considering I weighed one of the lightest geotextile fabrics available, and it was 2x heavier than the most commonly recommended thickness of plastic for vapor barrier applications. My short web search was only able to find geotextile with recycled content of 30% which would still mean more plastic overall based on weight measurement.

I love the idea of carpet padding (just as much as recycled billboard vinyl), and think it could work great in some soils but I doubt too many engineers would accept its use in the field. I can see it being very inconsistent with questionable permeability and filtration compared to commercial geotextile. I think most of it would not be permeable enough for most soils and would tend to clog. I found this interesting geotextile link but couldnt find much else out there on how carpet padding would compare with the engineered and tested commercial variety. As important as drainage is, I dont think these are frivolous considerations.

This exercise is largely an attempt to figure out the main objections of including plastic vapor barriers. Is it the evil of plastic manufacturing? Will the plastic cause problems? Thats not the way ancient builders did it? You seem to offer all these as reasons but Iam curious how your apparent acceptance of another form of plastic based technology compares.

At this point Brian, we are, I think, moving way too far off the topic of this post...

I used geo cloth as it is often spec'd by PE for projects, and felt carpet padding did meet the requirements for a project as a permeable separation barrier that has not affected the performance in drainage where ever I have seen it used.

Reasons not to use plastic:

Well the first...it just is not needed...which I have stated several times and we don't need to keep going in that circle...

Second, where I have had a chance to examine them...again as already stated...they are heavily compromised...so again...you do not need them if they are full of holes laceration and other elements of compromise...

Yes...there is not reason to keep promoting the chemical industries that manufacture them. If we can get to a point that plastic sare 100% recycle and or fully bio degradable to harmless organics/inorganics and or of a sustainable manufactured processes...then there would be something to examin...yet...if they aren't needed...why employ them...

If clay can do what plastic can...either as good or better...again...if ground moisture is even an issue after all the other elements of the foundation and design are done...why use plastics?

Well I want to thank you for letting me participate and thanks to all of permies for putting up with me. I dont think including below grade vapor barriers represents any meaningful sacrifice for natural or traditional builders and I think avoiding them in many situations introduces a lot of unneeded risk. I will try to make this my closing comments on the matter.

I have a passion for improving other's projects and feel like people need to be very careful when integrating parts of their structure with the ground. I think most engineers, scientists and researchers find that underground moisture does seek equilibrium and will readily do so through natural building materials given the opportunity. This is why building codes require vapor barriers for below grade interfaces.

Basement or underground wall situations are the most risky as they go the deepest underground. I recommend people avoid crawlspaces but if you must, consider building an unvented crawlspace.

I want people to be aware that outside of pier type construction, most of the building science community would be appalled that people would not include a vapor barrier for their ground to house interfaces. Contrary to the opinions and findings of the thread's author, the vast majority of scientists and independent researchers recommend them for controlling underground vapor movement and soil gases.

Again...what risk?

If we have been building dry structures (no not all of them mind you) for over 4000 years, why all of a student has the laws of physics and dynamics in architecture suddenly changed?

Building science, is a relatively new thing...not all these scientist do agree with many things being examined in the last 50 years...so lets leave the sciences and the many theories where they belong...in the laboratory and testing fields. I have a science back ground. I like science. I also know it is ever changing and probably one of the most dynamic and fluid constructs of the human condition.

I have been in around natural and traditional buildings for over 40 years, I think that awards me a certain degree of credibility. I have seen Mills on the sides of rivers, and sub, sub basements of old plantations homes in the south where the lowest level had a spring fed stream running through it, and other basements with "open water" either in a spring or stream running through. I have even ripped up concrete floors in basements and the concrete parging off the walls (the water sponge concrete usually is) and its vapor barriers in vintage homes with hideous moisture issues just to resolve the issue with better drainage, lime or cobb pointing and a raised wood floor and/or flag stone...in all these examples...What's the common denominator? Natural building principles, no plastics and a very dry space to live in and utilize in a much more holistic fashion.

So again...new science...or 4000 years of history...I leave it to the readers to decide and ask there own question as they may pertain to this post topic.

A 4000 year old structure offers valuable lessons on structural stability in the region it was built. It tells us nothing about how much energy its used to keep comfortable or quality of its indoor air.

"New" science has just as much to tell us as old, surviving architecture.

Again...we will have to leave it to the reader which has more value...

Science is transient at best I think, and it has been described that way as well in text such as..."the dynamic and fluid nature of the sciences..."

Often...very often..reversing itself and the views of hypotheses and conclusions about outcomes, particularly in complex systems of any order like nature, architecture, medicine and other complex systems. I know I was a Scientist for a short time, and have worked with countless members of this herd...to say it is fluid is an understatement. I would also have to point out the "politics" and "biases" that are bought and sold by funding grants are ever common. There is even a 12 years study claiming the positives of "saturated fats," now to be found in the annals of Science...just as one small example.

A 4000 year old structure offers valuable lessons on structural stability in the region it was built. It tells us nothing about how much energy its used to keep comfortable or quality of its indoor air.

I agree, they do offer valuable lessons and I hope that some of these could be view as even viable today if folks really take the time to study them and put them into practice. They are applicable, in my experience, whenever they are implemented for the specific biome they are designed for.

I can design what is being called a "green building" with HVAC systems and Heat Exchanging filtration and recovery systems, with super insulated closed cell foam walls, and other "modern amenities." This is a viable method and I have done it, and understand that others still are. I am, for the sake of this forum and my future endeavors to use natural and traditional modalities that can achieve exactly the same results. I think we become better facilitators, teachers and architectural designers when we can understand both modern and natural methods. This way I can correct, or augment a system with more natural modalities. Understanding them as intimately...that way real comparisons can be facilitated and create the paradigm shifts we need to have a more sustainable future in architecture in general.

A realization just clicked for me that helped me understand why this system works and I think it will help other people understand it much easier as well.
In Edward Fulkners book, "plowmans folly" he explains why plowing is detrimental to the health of crops. Plowing takes the top layer of soil, which is high in organic matter and field litter, and places it 8" below the surface. This layer of organic matter will completely stop the wicking action of the moisture in the soil, leaving the top 8" of dirt void of the needed moisture.

Putting a layer of rocks in between the earth and your floor will also leave anything above the rocks high and dry. Because moisture cannot wick thru gravel.

BING-GO!!

Philip...if I had a prize...you'd get it......and "apple" will have to suffice.

Plowing takes the top layer of soil, which is high in organic matter and field litter, and places it 8" below the surface. This layer of organic matter will completely stop the wicking action of the moisture in the soil, leaving the top 8" of dirt void of the needed moisture...Putting a layer of rocks in between the earth and your floor will also leave anything above the rocks high and dry. Because moisture cannot wick thru gravel.

This is not a real complicated equation...or as hard to really understand...especially...if the time is taken to study it, and then try building a few. With the site "raised" and the clay soils "packed and then layered with stone and gravel...then "raised" again, and the entire process done over with more stone and gravel and sometimes even more clay...all rounded off with a huge overhanging roof and you get a very high...and...very dry...island even in the wettest of areas of Japan...

So, extrapolating from a place like Japanese with its very similar biome types to our range here in North America the same can be immulated...again...no need for modernity to creep into the build...unless there is a specific reason or goal set.

Brian Knight wrote:I appreciate the thoughtful replies and I love the contrast between Bill and Jay's writings.

Bill, in your apple receiving post, you suggest that the main direction of vapor flow is from the inside to outside. For most locations, I believe the dominant direction of vapor flow is from the outside in.

Above grade, vapor can regularly travel in both directions. Underground things are different. Vapor is always trying to even itself out despite the temperature differences. I cant speak for the dry desert but most soils have moisture levels higher than what we want in our homes. The higher moisture levels of the ground will readily flow inwards towards a dry basement, slab or crawlspace despite any temperature differences.

Firstly; I see a lot of this argument having to do with where we are in our careers. Brian you are me 10 years ago, Jay I hope to be you in 10 years.

Brian, you may believe what you like, but the predominant driving force for subsoil vapor is temperature differential. Sheltered soil tends to be cooler than we like our homes to be, therefor vapor drives outward into the soil. As I said before, this is not always the case, but proper drainage and material selection can mitigate bulk water infiltration for those times when the soil is saturated, which happens even in the desert.

The 2 photos illustrate my point. The soil is completely saturated from heavy rains, yet the soil next to the basement wall is dry. If what you say is true, the soil would all be the same moisture level. The second photo is a grade mistake that is also dry even though water would run into this hole.

I appreciate the acknowledgments and hopefully I will be blessed enough to face many more humble pies in my future. Much like you guys have learned from those more experienced than yourselves, Ive had much personal instruction from those much smarter and more experienced than me. All teachers and instructors have different skill sets and experiences to pass down. I study, try to learn and post links from what the vast majority of building professionals see as the masters of science as it relates to our built structures.

While you guys seem to have been involved in various different occupations, some relating to this industry and some not, many of these building scientists have lives as long or longer than Jay yet have been studying successes and failures of buildings exclusively throughout their entire career. I feel this is a different skill set than what you guys offer. Its not necessarily better or worse but it takes a village.. Iam sure you see value in what the scientific community offers us, hopefully as much as we see the value in what you guys provide.

Please dont see this as a challenge, rather a healthy debate on the physics and choices relating to these issues thats meant to encourage learning for all, including myself. One of the main problems I see with evaluating very old structures is that they largely do not have the same level of Thermal control as called for by energy experts and building codes. When we make a wall or structure airtight and insulated, we completely change the physics. Many of these older examples have walls or roofs that IMO are closer to a barn in performance than a thermally efficient building envelope. A barn's walls are generally much more exposed to drainage and drying from both sides of a wall and will tend to last much longer than if we take those barn walls and make them thermally efficient walls.

I know all that jargon makes eyes glaze over, and Jay's been gracious to point out the pitfalls of science, but the guys publishing this stuff are not just pushing modern materials and are well versed in many ancient building techniques. Check out this Energy Vangaurd blogwhere Dr Joe points to igloos as the first passive houses. Many of Dr Joes writings and modern perspectives use the past for guidance and rightfully so!



To the issue thats forcing my seemingly unwelcome return to this thread is the assertion of dominant moisture flow below (or at) ground level. We are probably all guilty of over simplifying the issue. Here is a chart from BSC on the measurable forces at play in moisture movement:



Our disagreement involves the second law or thermodynamics, and as Dr Joe would say, its not rocket science.

While the law states that moisture does flow from warm to cold it also flows from more to less. I think most experts in this field recognize that the temperature differences between ground and basement are not nearly as strong as the moisture differences. Moisture will have no problem moving from mild to slightly warmer than mild as it seeks out its equilibrium.

This of course is just looking at the second law and there are other forces of nature at work here. Take a look at this illustration from Joe's pressure in buildings article.



Ive read in your other posts Bill, about your understanding and acknowledgment of recognizing and mitigating for this phenomenon, creating airtight ceilings to control thermal and moisture transport. Its another force that will easily overpower the slight temperature differences between ground and home.

Philips post is a great example relating to farming techniques but effecting moisture movement as it relates to our buildings? I liked Jay's follow up on packed clay and gravel layers better. Just be aware folks that gravel is a capillary break for bulk water and will not stop vapor. Packed clay will certainly do better but it will not stop vapor flow as well as a true modern vapor barrier.

I hope Iam not out of line by suggesting that if a site does not have good clay, the resources to bring it in could be more than the resources used of the more modern methods. Excavation, loading into a dumptruck, driving to the intended building site, and grading work to get it in place all of which will probably use a lot of fossil fuels. Then come this, first picture from Jay's link:



I dont know how many of you who have had the pleasure of packing dirt and rock but after 15 minutes of hand tamping, you would probably gladly mine, burn, frack a hundred times over than do it by hand compared to the efficiency and ease of one of these modern machines. Not saying its a fact or means much, but its likely the fuel used by this jumping jack will add up to more than the weight of plastic sheeting or foam.

Ahh then the gravel. If the site is extremely lucky, it has its own gravel or a natural source nearby. Otherwise, its usually mined and transported. Iam not sure about how many layers or volume of rock we're talking about and some sites will be more than others. Just keep in mind that concrete's biggest ingredient by far is gravel and there could be less material and environmental impact overall depending on the overall volumes of construction materials in play.

I also want to stress that building sites are highly variable. From site to site and from year to year. Groundwater fluctuates. We've built on sites that seemed safe and dry during initial evaluation only to discover that no matter how far you raised the pad, underground water or vapor is always a risk.

For the most part though, I think Jay is absolutely correct. Choose the right site, use the right methods and things will be hunky dory. I still think people need to take a very holistic view of materials, labor and costs when comparing and mixing modern and traditional forms.

Brian...you my friend are always welcome......just realize the goals of the forum are natural and traditional building...not modern methods wherever possible...

...And I will stress to other readers publicly that Brian and I have an old relationship outside of permies going back a few years. We can often get into heated debates on all manner of things "architecture related," yet if a potential client in the North Carolina area asked for reference to a good designer of an energy efficient home...Brian is at the top of the list, and this is me publicly saying so...

Now if this client wanted an all natural build...I would aim in a different direction yet still listen to, debate with, and have Brian on the design development team if possible for this region, just because you need the..."ya, but..." type of guy on any crew...

Now Brian, to your last post...

Like I have said before, I admire, know (have known) and appreciated "building scientists" and the work they do. I have worked with, and around "testing fields" and "real world lab settings." More and more each year is being discovered, (and rediscovered) as well as, many..."oh, I guess that isn't the way it works after all." This all right down to a University of Michigan's head of the building science department back 20 years now stating that "house wrap" and the concept of air tight homes will take 40 years to understand that it probably...over all...is not that great an idea... I still tend to agree with him, and other like him, on this point.

So yes, many do "feel" on this subject, as Brian does...others, myself included...do not...

The point about vintage architecture not possessing the same level of "thermal control," could very well be true of many (not all) of them...I agree.

This is not what is being suggested at all today in the realm of natural/traditional builds facilitated today. There are many, as a good example, today in the U.K, and other areas of Europe that are "upgrading" the thermal efficiency of timber frame infill systems (as just one example) by using a more thermally efficient cobb mixture and doubling wall thicknesses in new replication designs. Straw bale is another example of this, Just as Philip has shared. So, we can embrace completely what has been achieve in traditional builds and further enhance those same modalities by better understand them with today's eyes. I should also point out that here in North America, builders and the scientist that study them seem to fixate on "air tight" and "thermal efficiency" alone, while there Asian and European counterparts are just as focus on U factor. They actually focus on U factor so much that they don't even use R factor when designing wall in many cases...so there is an entirely different perspective from the same herd of the "science lot."

So, since barns are used as an example and this is a mainstay of my business for clients in part of what I do...I will agree that barns, in the first part of their life, do indeed have air circulating on both sides, and would not render the most comfortable place to live in a thermally dynamic environ...However, barns are also timber frames, and as such, as are many other vintage timber frames from around the globe, more than capable of supporting a very efficient, very permeable (and draft proof "all natural" materials and/or recycled) thermal foundation, wall and roof diaphragms. If they could not do this, I would be very much out of business, and the clients would very much not be pleased with me.

Allison Bailes wrote:He (Dr. Joe Lstiburek) also showed a lot of photos (from the 1980's) of his early projects and the failures they had to work through. My favorite was the house where they were going to embed ducts in the slab and then had to fight to get them to stay down as they floated in the wet concrete.

Brain, your links and the above passage kind of illustrates my point about "building scientist" (now turned business people as the links are from dot coms...not dot orgs.) I have been reading, watching and listening to Dr. Lstiburek, et al, for over thirty years...they do not all agree with each other by a long shot....and...as illustrated in the above passage have been selling their "experiments" to the consumer public since the late 70's...Each permermation of "we got the best way.." all backed up by "science" and deep convictions of their ability to build "better architecture" with "better methods," in each of the permutations and evolutionary steps in every decade I have been watching and observing...guess what...they (scientists and building experts) are still getting it wrong and arguing about it...

What have I seen?

Well, as much.."oh...we got that wrong..." as I have seen..."well that seems to work...maybe...I think...."

Again, being a permaculture site, we want to experiment, study and compare "natural and traditional" modalities to achieve these "efficiency goals" and concepts and leave the other stuff too big industry and those, like Dr. Lstiburek, that get much of their past (and present?) funding stream from these industrial intatties. As I said earlier, yes there is science on both sides...there are also agendas...I tend to like and trust the permaculture crowds agendas and the scientist in this realm much more than I do the "Dr. Joe's" of the building world.

I also have to latch onto the Eskimo's igloo comparison, as I work indirectly with Athabascan cultural groups and the "modern architecture" with diesel generators operating them so they will work properly (ie, heater, air exchangers, recovery units, etc.) All the while the oceans are rising do to global warming. Who funds much of this development, and architectural normative development?...Yes the government of Canada..but follow the funding for the architecture and the research behind it far enough and what do you get...Guess folks...

"Big oil..."

Sorry, not the root of a tree I want to take "knowledge fruit," from.

Now, do to this cultural influence on a former nomadic people, we have a heavy dependence on food that is not good for them, loss of hunting knowledge, dependance on big industry, and the list goes on. Those holding out and still practicing the "old ways" as much as they can are living in those igloos and other fossorial architecture. By the way, R2 per inch on an "ice pack" deep winter igloo (I won't get into the other vernacular types) will yield a structure you can heat to over 40 degrees f by lamp and/or body heat...as the R factor of the wall is an average of over 72!, and that not including the traditional fur linings...


I could (I won't) get into the above chart on "Moisture Transport In Assemblies," as it is as subjective and interpretive as everything I could write in the next ten paragraphs as a rebuttal. Suffice it to say, the chart is interpretive, potentially aberrant from an extrapolative perspective, and probably entirely too generic to really apply to specifics. The "capillary" part I could write a chapter on alone as there is virtually zero "capillarity" in any of these materials and only "cohesive diffusion," which is a point of ongoing scientific debate...

While the law states that moisture does flow from warm to cold it also flows from more to less.

Yes, and there is still great debate over which "engine" is primary and which is secondary, and how often they may "zero out," overlap, or fluctuate... Again, using a limited "information stream" such as BSI is not a great path to go down...in my view... (Which I encourage all readers to follow and read to draw their own conclusions about "agendas," and information applicability or complete accuracy, as some of it is o.k. some good, and some very subjective in view.)

...Just be aware folks that gravel is a capillary break for bulk water and will not stop vapor...

Stone and gravel...actually...is a mitigator of "cohesive diffusion" as there are zero structures of "capillarity" in gravel or stone...another often misstated misnomer even among alleged experts, and the gravel also is a "diffusions matrix" as well that is still poorly understood...other than we know that it works. The latter being so poorly understood even among experts and often just ignored like so much else in the building trades when pushing a particular agenda...this field is full of them...so one aspect will be over emphasized and studied (often for convenience and/or agenda) while another ignored. Packed stone and gravel does indeed diffuse moisture vapor, and when working in concert with the complete system presents as rendering it virtually a non issue...that coming from experience and the knowledge to build such foundations...not just reading about them...

Packed clay will certainly do better but it will not stop vapor flow as well as a true modern vapor barrier.

Please agree, this is a subjective view, because my investigation into this modality, and years of observation show that it is not only as good, it is better in many ways and it can not be damage by puncture or chronological compromise...A "clay layer" will last millenia, even through heavy tectonic activity, and one of the reasons in reached its zenith in development in a places like the Ryukyu Arc. Plastics, and their application, are so new, we are just learning that many issues with them, form organic estrogen mimicry to affecting us in ways we still don't understand...

The clay layers is a extremely effective at mitigating, diffusion and inhibiting moisture and vapor migration in an upward direction, yet still seems to be highly permeable when applied in walls, which also reflects the same characteristics as where we lose heat out of buildings...roof first, then walls second, and only some downward...

As for comparative analysis of plastics to "tectonic compactors" that too is subjective...Having spent many thousand of hours now doing this both by hand in a traditional line with others alongside and behind the machine, I can share that I can often fill up the little tank on the one of the compactors that I own and go for well over a day sometimes, and use only a small amount of fuel that is either biodiesel or alcohol...so I am sorry, I think that is a non starter here worth comparing or discussing....

For the most part though, I think Jay is absolutely correct. Choose the right site, use the right methods and things will be hunky dory. I still think people need to take a very holistic view of materials, labor and costs when comparing and mixing modern and traditional forms.

And, one must have a really good history in both traditional and natural/traditional modalities, as well as modern methods (I think I have that covered within reason...) to have a good understanding of those comparatives, and systems. The "transported of gravel" and other challenges are indeed comparatives to look at, yet most sites will often yield those elements to be used in a completely traditional way over transport or a compromise between the two. Over all, in 40 years of thinking, watching, reading, studying and observing...little of modern has sway over what I have seen achieved in traditional systems of architecture....but that is just my experience....

Regards,

j

Gudday,
I was reading the usual advice re moisture barriers on a Natural Building page on FB when someone chimed in with this link: webpage: Griffin Soil - can I get your opinion on ths, Jay C.? Is there a hope that I could convince a council to allow me use this under an earthen floor instead of a plastic moisture barrier? We live in the sub-tropics in South East Queensland.
Adrienne

Is there a hope that I could convince a council to allow me use this under an earthen floor instead of a plastic moisture barrier? We live in the sub-tropics in South East Queensland.

I would say yes Adrienne, and one of the things I do for folks like you if the case is not to complicated. I often write "recommendation reports" for "alternative systems" not that any of them are actually that alternative...Most have been around way longer than the modern..."well maybe this will work?"...concepts. You could possibly just find a good natural builder in your region to also lend support and if you can, find a PE with a background in and support for "traditional and natural building practices."

Lime earth stabilization is very much part of many "raised earth foundation" practices. Thank you for bring attention to that with your link!

Regards,

j