Raised Earth Foundations

Thanks Jay,
I found this video and hoped you could comment on it? I was surprised to see them using water on the soil (clay?) before building the wall. IS that a traditional foundation?




Adrienne

Hi Adrienne, et al,

The video does seem to be presenting an interpretation of a traditional system, yet without knowing the local biome and location it is hard to interpret elements. This "appears" to be a semi arid region perhaps with a 'monsoon season,' so they stratify rubble and clay soil mortar as they fill the foundation trench. This is meant to stabilize and protect the rubble from silting in. This "clay soil" may well have lime added to it, as some methods employ a clay/lime mortar matrix. The layer you see being "wetted" is a bedding mortar for the first course of stone. Many stone structures around the globe use clay or clay/lime mortar...especially in the interstitial regions of thicker walls like Castles and related heavy mass stone structures.

Hope that sheds some light on this...

j

Jay, I seen this foundation driving around. Does it resemble a raised earth? I never seen anything like it. Steel I-beams sitting on large rock. What architectural style home is this? Asian?

Hello; I am new to this forum and have a question about building a timber frame cabin foundation. My build site is in the Adirondacks on a small hill with a high water table. I have hand dug to a depth of 4 foot and found small rocks to 2 feet,then sand and water at about 3 feet.My question is this; can I use a granite pier foundation on gravel? I'm no fan of concrete and would prefer using the raw materials on site.

Hi John,
Welcome to permies.

I would recommend using local materials over industrialized products for all your building needs. I can tell you from 30 years' experience that these materials feed your soul while working with the factory produced stuff is just work.

The podlii foundation system is well suited for what you have described.

I can talk you through this on your own, or in August Jay C. White Cloud and I are putting on an Asian timber frame workshop in Utah where we will be building a walipini/workshop with a podlii foundation. We'll be doing this in August; starting the foundation around the 1st. Cost is $625 for the 10 day workshop with lunch included every day. The foundation and plaster workshops before and after are free to all timber participants.

Terry Ruth wrote:Jay, I seen this foundation driving around. Does it resemble a raised earth? I never seen anything like it. Steel I-beams sitting on large rock. What architectural style home is this? Asian?

Hi Terry,

I don't know this home, but it sure looks like Frank Lloyd Wright had a hand in the design.

Asian architecture was featured at the World Expo around the turn of the 20th century, igniting passions among the finest architects at the time like Frank, Greene and Greene and Gustav Stickley to name but a few who designed many Asian influenced western buildings.

Thank You Bill, I would like to learn more about Podlii foundation design.Recently I have begun a new job at the Railroad and do not have any vacation time yet.I would not be able to travel to Utah at this time.My timber frame cabin will have12 piers and measure 24x40,with a loft.I have purchased a Norwood sawmill to make all the lumber and would love to use the pink granite on site for the foundation and fireplace.I have 8 acres of dense Forrest to chose from. I'm thinking Hemlock for the frame and Yellow Birch and Sugar Maple for the flooring.I'm not interested in insulation and would like to make as small as possible impact on the property by doing most work by hand.Where can I research Podlii foundation design?

Hi John,
I could give you a partial answer, but why don't we let the master speak for himself;


"...My timber frame cabin will have 12 piers and measure 24x40,with a
loft..."

That is a good starter size for a beginning family...

I am not sure I would have recommended a "Norwood" but if the price was good and it is the larger size that can handle 30" bolts, you should be pleased.

Pink Granite plinth stones or running wall foundation should be fine. There are several ways to do it as you can imagine. The "Longo Barn" is one example of what two of my students cut a few years back. Let me know what you think?

Wood selection sounds great. Both the Birch and the Maple make great flooring, but can be a "bit active" and cantankerous as they move so much. I would probably not recommend "nailing them down" and instead either do a "jointed floating floor" and/or do a Korean 청마루 Cheong Maru style floor of some fashion like this example I did...here

As for the Podii or Podium systems, the best info is in Chinese, Korean, Japanese and a few others none English sites. I seem to have done the most writing on the subject, for the most part, that can be found in English that may not be buried in academic papers within the library stacks of some colleges.

What you find on Permies that I wrote and some of the following from my own files on the subject may help:

Foundation Anatomy:

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Ishi no ue ni hashira ga tatte imasu. 石の上に柱がたっています。Pillar stands on top of the stone.
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Kore o Ishiba-tate to iu sōdesu. これを石場立てというそうです。This is the so called Ishiba stand.
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Nunogiso 布基礎 Continuous Stone Footing-Nunogiso
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Hottate 掘立て Post in ground foundation system
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Hashira no nemoto 柱の根元 The base of the pillar
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Tamaishi kiso玉石基礎Cobblestone Foundation
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Tsukaishi 束石 liter. “bunch stone.” These stone posts come in many forms.
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Neishi 根石 Plinth(root stone)
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Soseki 礎石 Foundation Stone
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Hashira ashi 柱脚 Column Base-Bracket
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Ishi 石 Stone
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Tamaishi 玉石 Boulder (ball stone)
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Ishiba 石場
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Hashira ga ishi no ue ni 柱が石の上に On pillars of stone
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Guriishi or Kuriishi 栗石 The Chestnut stone for packing around foundations and often used on better made Hottate systems.
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Wari guri ishi 割栗石 functions the same as above when performing preliminary foundation work Djigyō 地業 through the process of Warigurichigyō 割栗地業 which required the proper use of gravel jari 砂利, sand work Sunaji-gyō 砂地業, Tama Ishi 玉石, or the above kuri-Ishi 栗石 was hand packed then tamped into place.
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Kiso 基礎 The footing or foundation of a building.
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Xiájiān shí 狭間石 Are the often dry laid stone found under Castles and other “raised earth and stone” foundations.
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Kindan 基壇 (Jaanus Definition for this foundation type.) This “podii” (danjouzumi 壇上積) or “podium” of raised stone and earth forms a platform in many Asian temples and vernacular folk architectural types from the Middle East through India, China, Korea, and into Japan. This is very distinct in design and is broken down into several basic elemental forms.
o

Kamebara 亀腹 This is a rounded mound covered in white lime and/or clay plaster. It in turn can support base stones *soseki 礎石 or other supporting members for a wooden floor itayuka 板床 and building framework *jiku 軸.


If you take the "kanji" above and stick them in a google search line, you can find more info. I have some also in Korean and Chinese but the above should more that satisfy what you are seeking. I have to get to writing a book or I am going to start "leaking info" soon....

We can discuss insulation and other items later.

Regards,

Thank You Bill! I will search Google for info. I would like to go with a large single piece of Granite if possible. That would save lots of time and I think would look great. I just have to find or quarry 12 large pieces for the piers.

JT

Hey Jay and everyone else,

I just read this thread from start to finish, and I am happy to say that it was super duper educational. What a roller coaster of conversation! I have to applaud you Jay for being so articulate with the english language. Not only that, but the energy and thought you put into this thread far exceeds any conversation I have ever experienced. So, I appreciate your knowledge and wisdom, but I do have a couple questions if you would be kind enough to answer them.

Now, I know that each building must be designed based on location, but I want to ask about Earth Berms. First of all, when would they be appropriate and advantageous? My guess is that as long as you could design the earth around the house to drain the water away from the structure you would be fine.(french drain possibly?) Second, could you combine a Earth Bermed house with a raised foundation? Third, is straw bale or rice haul construction combined with breathable lime plaster an approbate infill for timber framing? What are the advantages and disadvantages to whole log framing vs timber framing? Do you think rain water collection of your roof can be used in conjunction with natural building? If so, would you use Pro Panel metal roofing or a different natural product? Here are just a couple of questions I had tonight, I hope I didn't ask to much. Thanks for everything so far, I have learned so much! Oh and I am hiking the Appalachian Trail this monday! It is my last adventure before I settle down to build a house and permaculture environment. Yay, you guys kick ass!

Peace and Love
Gabe aka Remedy

Hey Terry,

I posted a response way back when to you...don't know what happened?? Bill B. got to you though and I concur...it looks like a FLW influenced work from his latter attempts at modernism. There is a 'faux' podii foundation and has elements of both Asian and Mayan/Inca architecture, with a smattering of Syrian found in some of the motif. Very interesting...would have loved to seen it as a true "natural-traditional" build instead of all the "faux work" it has on it...

John Thomas, I hope Bill B's posting that I shared with him offline was of some assistance in your research...feel free to call any time...

Hello Gabriel G.,

Thank you deeply for the kind words and I am very pleased you found this post of interest and value. Now to your query:

Now, I know that each building must be designed based on location, but I want to ask about Earth Berms. First of all, when would they be appropriate and advantageous? My guess is that as long as you could design the earth around the house to drain the water away from the structure you would be fine.(french drain possibly?)

I believe this is perhaps a matter of aesthetic for many, yet I would suggest that almost all of the enduring forms of architecture in the world rest upon some form of dais (i.e. podii, platform, mound, rostrum, berm etc.) such as the Japanese 基壇 "kidan". So with that understanding, almost all building sites will benefit from some form of "raising above grade" for the architecture in question, be it on stilts or just on a raised mound of earth and stone.

Second, could you combine a Earth Bermed house with a raised foundation?

I would say generically...yes...yet would have to see each individual case to ascertain the most applicable architectural forms for a given local.

Third, is straw bale or rice haul construction combined with breathable lime plaster an appropriate infill for timber framing?

Absolutely in the most generic of responses for such architecture. This is a the way of it for most of these over the last several thousand years and only as late has it been a trend to adulterate such architecture with methods of modernity...often with very poor outcomes.

What are the advantages and disadvantages to whole log framing vs timber framing?

Depends...

This battle will rage for decades among us 'traditionalists,' and most of our debates are academic over historical context and anthropological interest more than applicability aspects of form for a give local. There are subjective points around both forms in regard to sit applicability. If you have lots of trees, the means and methods at your disposal then I suggest that when both styles are employed the architecture these render are virtually unbeatable in all aspects of form, aesthetics and function.

Do you think rainwater collection of your roof can be used in conjunction with natural building? If so, would you use Pro Panel metal roofing or a different natural product?

Yes...in almost all cases, unless there are issues with acid rain or other pollutants being elevated in a given area's precipitants. I can not say I am overly familiar with "pro panel" but most standing seam metal roofs would yield a potable water from all I have learned, and experienced. I would still test and check my water for any new build if doing "rainwater harvesting."

Here are just a couple of questions I had tonight, I hope I didn't ask too much. Thanks for everything so far, I have learned so much! Oh and I am hiking the Appalachian Trail this monday! It is my last adventure before I settle down to build a house and permaculture environment. Yay, you guys kick ass!

Have a great time on the A.T....I have guided many sections of it, and please enjoy the many shelters...my friends/students have designed and built several of them...like the "velvet rocks shelter" in Hanover, New Hampshire...Be safe, and have fun!!

Regards,

j

Yes Jay, the wealth of information was awesome! You really should publish a reference book! Thank You!

As soon as the snow melts I will start digging down by hand to a depth of 48 inches and tamping item 4 stone.
Then I will add rock vertically in a herringbone pattern to grade level.
My plan is to shape pink granite blocks 30x40,with a height of 32 inches,similar in size to a old railroad bridge foundation.

My question is,should I attach my Hemlock 8x10 sill beams to the granite blocks? Lag shield anchor,or just use gravity with a rebar pin for wind shear?

Wow, what a great discussion. Thank you Jay and Bill for sharing all your knowledge.

Here's where I'm at. I am not a builder by trade so I tend to mull ideas over for quite some time before executing and wanting to build with minimal impact on the land is always foremost in my thoughts which makes the mulling that much longer. I am planning on putting up a shop/pottery studio soon and have been contemplating foundation choices for sometime now and it seems the raised earth foundation or a variation of it may be just what I've been looking for. I will be building on what is now my parking area which is built up runs of stone and bank run gravel that is compacted. What I'd like to do is add layers of compacted stone directly on top of the existing stone/gravel and then place some plinth stones and build from there. I have a couple of questions and was hoping for some thoughts/suggestions.

First, what size stone and how deep of a run before compacting and should the size of stone get smaller for the final run to help with drainage? How deep total would I need to go? (I have a feeling that last one will be answered with something beginning with "It depends..." )

The second is similar to what John is asking regarding tying the building to the ground. Does the weight of a timber framed building alone negate the need for securing it to the ground?

Finally, a bit off topic but in relation to it, with regards to insulating the floor of a building that sits on this type of foundation. What are the most effective options?

Thank you in advance for your thoughts!

Hi John and Rob,

Yes, like most natural things it depends.

Check out this video thread and then ask more detailed questions that include what style of building and details of your biome.

Korean Hanok

All Blessings,
Bill

Hello Everyone!!

john thomas wrote:As soon as the snow melts I will start digging down by hand to a depth of 48 inches and tamping item 4 stone. Then I will add rock vertically in a herringbone pattern to grade level.
My plan is to shape pink granite blocks 30x40,with a height of 32 inches,similar in size to a old railroad bridge foundation.

Excellent...absolutely "bomb proof" and I mean that literally. The structures of wood and stone hit my our bombs on Japan at the end of WWII (including nuclear) actually withstood such impacts. Even dry laid stone in the "herring bone" pattern withstands millenia of earthquakes, drains water better, and actually "gets tighter" with age, unlike "ashlar" methods of laying stone which can shift and loosen.

john thomas wrote:My question is,should I attach my Hemlock 8x10 sill beams to the granite blocks? Lag shield anchor,or just use gravity with a rebar pin for wind shear?

John this entire subject of "attached framing" is a very interesting one that I have studied for decades now. I can honestly say that over the last 4 decades (and thousands of pages of reading and field observation) I think this is 20% a practice of logical design in some applications and/or forms of architecture, while 80% of the rest of it is "psychology" having little to do with a logical reasons.

I will validate with some examples and stories.

First, if a well designed foundation and timber frame can..."just sit"...in a place like Japan for 2000 years...then the entire concept of "attaching" is rather moot in many applications. I have actually...more than once...had these types of discussions with Engineers which too often stand entirely too close to a subject without taking a step back and really looking at the big picture. They (PE that is) will solve one problem (too often) and create 6 more they don't see.

As an example, after seasons of major wind events in places like southern Louisiana, the PE there thought it wise and prudent to do away with "overhanging roof eaves." This was even placed into local building code, and much of the "rescue and rebuild" funding demanded that "eaves be removed and/or not built." So now we have structures in a hot humid climate, lots of water and..."NO EAVES!!" What does that give us...??

Well, very hot interiors that now have to be overly air conditioned and water infiltration at the eave line between roof and wall... Their logic is that now..."if"...a hurricane directly hits the structure the roof will have a better chance of surviving...

This is turning out (as many of us knew it would) to be utter nonsense. Why?

Well...the simple reality is...if a tornado or hurricane of any strength directly impacts most architecture (short of bomb shelters) it is going to damaged or completely destroyed that architecture, and the roof almost always comes of. That is kind'a the nature of nature, and big disasters..."stuff gets chewed up bad..." So here we see a PE solution that was moot, without any consideration or regard to vernacular designs of the region, and actually created many issues that now are coming to light and the buildings have either go under routine repair for water damage and overheating or...torn down to be built again...some in the same silly way...?? All the while in close proximity there are local Creole structures over 150 years old still standing...One more example of "modern folks" and their hubris that they can "do it better,"...

So, without seeing a building site and some photos I can't really say for certain about your project... but I would wager that you don't even need the rebar pins. Timber frames tend to sit on their foundations really well, and for very long periods of time...Unless...something big happens...Then we just typically put them back onto their foundations...Something you can't do with "stick built" modern buildings, or those built out of cinder blocks and others such methods of modernity...

Rob Viglas wrote:First, what size stone and how deep of a run before compacting and should the size of stone get smaller for the final run to help with drainage? How deep total would I need to go? (I have a feeling that last one will be answered with something beginning with "It depends..." )

First Rob, thanks for joining the discussion...

I think you would benefit from reading about "angle of repose" and seeing what else is on the "net" for "plate compact" and "gravel trench foundations." These will give you a great deal of insight into what you plan on doing in the future.

Each layer you place is called a "lift" and they are typically (depending on material's angle of repose and other characteristics) laid in 200mm to 300mm lifts for most "crush run" stone in the 30mm to 100mm size range.

Depth is depended on design, soil types, and building site. Get us some photos and plans and we can give better advice.

Rob Viglas wrote:The second is similar to what John is asking regarding tying the building to the ground. Does the weight of a timber framed building alone negate the need for securing it to the ground?

Weight does have a lot to do with it, and also just the general aspects of gravity and how it "actually" interacts with architecture in relationship to tectonic events, both wind and seismic. Drift pins are warranted at times, yet actually "tying down" a structure I only do because PE and code demands it...

Rob Viglas wrote:Finally, a bit off topic but in relation to it, with regards to insulating the floor of a building that sits on this type of foundation. What are the most effective options?

Two forms come to mind typically as the easiest and best practice overall.

1. If going the "all natural" route...I would personally have really come to love the "straw (or wood chip) clay slip" infill methods. These are nothing more than "insulative forms" of other styles of cobb work.

2. Mineral wool board and/or batting which can work in concert ver well with the one above there by adding a thermal break and more insulation in less space.

There natural insulation types but there cons compared to the two above often outweigh there use in my view with most applications...

(Bill, I am sending you and email...look for it. I have some stuff to go over and want to touch base on some other things also...)

I'm not sure if I should just start a new post, but I would love input on building a barn on a hill with a composting floor

I started a new post thread for you Skye about this barn project...please give details and questions...

Regards,

j

I read through this post once before, but decided to read through it again and have understood it so much better for doing so.

Jay, since the topic of this thread is the raised earth foundation, could you describe it in a bit more detail?

I'm confused about the interface between earth and ground (and whether there is one). So you start by digging down deep, then filling it all with packed gravel. I can see how this mitigates moisture issues as the rain drains away and the moisture from the earth can't get up to the floor of the house. I am also supposing that any condensation or dew that forms on the gravel/rocks drains downwards due to gravity. You place big foundation stones in the corners (and perhaps more than that) or stacked stones as either plinths or a continuous foundation wall - but with the latter it is a "vented crawlspace"...do I have this right so far? I'm assuming it is "vented" or open on the sides so that air can flow through and circulate and dry out any moisture there such as dew or condensation, much like the old "leaky walls" of buildings kept them dry (albeit very drafty; not an issue when it's under a floor).

Now where I'm confused: Where does the packed earth come in? Is this put directly on top of the gravel? Why is it called "raised earth" then? If the packed earth floor sits above the ground then what hold it in place (on the bottom)?

This is a great thread!

I've just re-read the entire thing, and while coming from a more modern construction background, am so intrigued by these building methods! Thanks to all for sharing their knowledge and experiences.

Jay, I know this is slightly off topic... but could these techniques be used in a hillside/walkout design? Is there a good way to approach that design goal without using OPC? Our new property has some great locations for slope side living, and I really like the idea of having a two level walkout design. While I'm not against using OPC, I would certainly be interested in learning ways to not use it for these scenarios. We are in the way early design stages of a slightly larger house than the cabin I have discussed in other posts, and are open to any new directions at this point.


Thanks

Hi Folks...sorry I missed that I had questions here...so I will do my best to cover them...

Jay, since the topic of this thread is the raised earth foundation, could you describe it in a bit more detail?

Hmmm...well in its most simple definition past what I have gone into details over...it is a raised "kidan" (aka podii or dais) of packed clay earth and stone. There are many vernacular forms in a number of cultures, but those of Asia to the Middle East seem to be the most well laid out and enduring. As for detail, other than taking one example and going step by step through its construction process (equal to a small book) I can't really cover more than I have here already, but I would gladly answer specifics to what is found in the many "links."

As to the "confusion" part...that is o.k. many are that just start cold in studying this vernacular system...In short, some are "zero entry" style structures that sit atop the podii while others are further raised (my preferred style) on stone plinth/socle. None should be or need to be "drafty" or in modern terms..."inefficient."

Now where I'm confused: Where does the packed earth come in? Is this put directly on top of the gravel? Why is it called "raised earth" then? If the packed earth floor sits above the ground then what hold it in place (on the bottom)?

The "packed" part comes from the fact that all the different elements (clay and stone) is not just "dropped" but "placed and packed into form and purpose it is servicing...

It is called "raised earth" because it is comprised of earth as well as stone and "rises" above the sites "natural grade."

What holds it in place...is stone and/or rammed earth in most of the vernacular designs...

I know this is slightly off topic... but could these techniques be used in a hillside/walkout design?

Absolutely and to good effect in my view...

Is there a good way to approach that design goal without using OPC?

In short...YES!!

None of of the methods I have studied, promote or profiled in this post thread require concrete at all! I wrote this for the clear intent of giving folks an natural, durable, and well proven alternative to "opc concretes" and other modern building methods for foundations...

With "specific" plans, and site descriptions and more detailed formate could be discussed.

Regards,

j

It is called "raised earth" because it is comprised of earth as well as stone and "rises" above the sites "natural grade."...What holds it in place...is stone and/or rammed earth in most of the vernacular designs...

Oh, I think I get it. Kind of like how "raised beds" (for gardening) aren't "up off the ground" but just "higher than ground level". Thanks!

This is a great topic, thanks Jay for posting it! It gets right at something that has been bugging me for a while trying to learn about "natural building". I have really been surprised how common plastic membranes are. Now, I don't have any qualms with people choosing what they want for their house. I don't think everything we do has to be ideologically driven, but in terms of championing natural building as an architectural form I do see a problem with reliance on plastics. For my own house I have been looking for an alternative and looking to older techniques, I don't want to live on top of a sheet of plastic, and rightly or wrongly there are a few reasons I want to avoid it. Particularly as I am a complete novice builder. It has been really hard to find much info that doesn't use concrete or plastic. I am really grateful for the info here on Japanese foundations.
I don't have a complex understanding of capillary action or the physics of water movement, but I think its okay for me to come to this thought anyway. My main concern is this:
Plastic has a set lifespan and it is not as long as I want my house to last. So at some stage that membrane that is integral to my house being healthy and sound will break down. Because the plastic is buried beneath my floor it worries me that I would have no idea when and if the integrity of the plastic is compromised. I worry about anything in the 'system' of the house being hidden so I can't see if there is a problem. How will I know if the membrane deteriorates or punctures? I also don't like the membrane approach or the concrete slab approach because it seems to create "battlefront" water vs human technology right under our house and I doubt we can win that one. If the moisture is kept out of the house under a membrane surely it will just pool?
There is another point I would like to throw in the mix. Houses and the approaches we use work as a system. I really worry about anything that mixes old and new systems that work in completely different ways. It seems like a recipe for problems down the track. For example a house design "system" that relies on the exclusion of water and being sealed in watertight, in my mind should not be mixed with methods that rely on breathability. I see a problem with one approach for the foundations and another for the walls, for they seem to work together. Now, I am no expert in any of this, but it's just how I am thinking about it all as I learn.
Here is something I found informative, maybe because of the nifty diagram. It's also one of the few approaches I have found that doesn't use concrete or plastic somewhere in the design. This approach uses a breathable limecrete floor over graded gravel layers. Its designed to be able to be retro-fitted to old lime cob houses also. Some also use an aerated glass product as a water resistant but breathable layer. The other design uses aerated clay as insulation. I wondered if just a layer of tumbled glass could work? They use breathable geo-textile membranes to keep the layers separated as they are constructed and the limecrete out of the gravel. It gave me some good ideas, but now I am off to research podii making an extended platform foundation...keeping the water well away from the house seems a great approach.
http://www.limecrete.net

Hello Fianou,

​I have really been surprised how common plastic membranes are. Now, I don't have any qualms with people ​​choosing what they want for their house. I don't think everything we do has to be ideologically driven, but in terms of championing natural building as an architectural form I do see a problem with reliance on plastics.

​Very well put...I like the way you wrote that...!

I often come across perhaps to "ideological" and I really don't mean to. I am just trying to do my best at following a foundational logic, that if natural building is to be "natural" (aka traditional) it can't have all this heavily industrialized materials.​

​The second part is just "simplicity." ​We have not even come close to matching the durability of traditional and ancient building materials or methods...Most modern elements of the "built environment" (aka bridges, highways, commercial/domestic architecture etc) are showing signs of extreme wear, aesthetic compromise, and often difficult/expensive maintenance in less than a few decades. In comparison, the oldest wooden structures look very much the same as they did 500 to 2000 years ago when first built. In stone this is measured in many millenia...None of these have ever relied on "plastics" to function...and...function very well! It is only a broken construction industry and the contractors that facilitate these modalities that insist they are necessary...or "good practice."

For my own house I have been looking for an alternative and looking to older techniques, I don't want to live on top of a sheet of plastic, and rightly or wrongly there are a few reasons I want to avoid i​t.

​Good!...It really isn't necessary and I commend you for seeking to look deeper into this subject..​.

I don't have a complex understanding of capillary action or the physics of water movement, but I think its okay for me to come to this thought anyway. ​

I would note that many "Scientist" don't even have a really good handle of "true capillarity" and I have seen some deep, lengthy and sometimes comically heated debates over the subject. My Geology professor, many decades ago, actually was the first to acknowledge this in our discussions. For example, only organic tissue has "true capillaries" and other than man made capillaries or some rather rare geologic crystalline filiform (e.g.​ "zeolit")...you won't find "capillaries" or "capillarity" in any building material​ or minerals in general​...

We will find the effect of "cohesive diffusion" in the interstitial micro and macro spaces of the structural matrix of many materials (sometime referred to as "pore structure")...However...this behaves rather differently than "true capillarity"...​

My main concern is this:
Plastic has a set lifespan and it is not as long as I want my house to last. So at some stage that membrane that is integral to my house being healthy and sound will break down. Because the plastic is buried beneath my floor it worries me that I would have no idea when and if the integrity of the plastic is compromised.​

Actually most are very compromise from the moment they are laid and built with. Most are heavily punctured, torn and further degraded just in the building process itself, which has lead many to ask the question...Why even use them?​ The second, is how long will they last, what are they doing, how would you replace them and is it (again) even worth employing them in the first place?

I worry about anything in the 'system' of the house being hidden so I can't see if there is a problem.

​This is actually a concept in "better architecture" that is part of "disentanglement." There by all elements of a structure should be fully inspectable, and/or maintainable/replaceable whenever tangibly or feasibly possible.​ ​ This goes for every aspect of architecture such as plumbing, wiring, and anything in any "interstitial zone" of a building...​

How will I know if the membrane deteriorates or punctures? I also don't like the membrane approach or the concrete slab approach because it seems to create "battlefront" water vs human technology right under our house and I doubt we can win that one. If the moisture is kept out of the house under a membrane surely it will just pool?

​Wow...another well written query and understanding...and...very true in my experience. Humans never are really able to "force" nature to behave the way they want (or think) it should or will. Especially water...It is much better to embrace it, and work with it and/or remove its 'vehicles of transport."
​

Here is something I found informative, maybe because of the nifty diagram. It's also one of the few approaches I have found that doesn't use concrete or plastic somewhere in the design. This approach uses a breathable limecrete floor over graded gravel layers.

​This is a perfect example of a "raised earth foundation" form as they are employed today. I am very pleased that folks have found this post not only informative, but provides them with a very ancient method to achieve "dry architecture" without modern "waterproof" concepts that really never seem to work as intended or for very long...

Thanks again for your comments and observations...​

Rethinking this issue lately.... I was watching a bollywood movie (Lagaan) with my son and the villagers live in earth houses on a platform! So i started think about this again.
It has struck me that the podii approach of having a large platform foundation is superior to the common method of building foundations under walls that I see in natural buildings like cob. My cob handbook says to build a trench under the foundations and then stick in a pipe and then build the foundation over that. Now, in my head I have a problem with that. Surely by building a trench under the wall you are essentially inviting water to gather ( at the lowest point) and somehow expecting a plastic pipe and whatever method of building the foundation to stop water from rising up into the cob? What if there is a lot more water than the pipe is able to handle?Surely that is not the best way to do it? Wouldn't it be better to have that drainage trench as far from the wall as possible? I would have favoured open drainage trenches filled with gravel, or just open so the water moves. My grandfathers house was built like that, it was concrete, but in the tropics of malaysia they had a lot of rain, and instead of gutters used open trenches like a moat around the house, the water moved away much better because it was free moving and able to evaporate, rather than soaking into the ground. Could you use like a podi foundation with a dry riverbed drain around the outside channelling water into a rain garden?

Hello Fianou,

I'm glad you have enjoy reading this post thread. I will try to answer and/or address your question/comments.

It has struck me that the podii approach of having a large platform foundation is superior to the common method of building foundations under walls that I see in natural buildings like cob. My cob handbook says to build a trench under the foundations and then stick in a pipe and then build the foundation over that. Now, in my head I have a problem with that. Surely by building a trench under the wall you are essentially inviting water to gather ( at the lowest point) and somehow expecting a plastic pipe and whatever method of building the foundation to stop water from rising up into the cob?

The many different cultures that employ podii (aka dias, kindan and other "raised earth" and "plinth and post" foundations,) have proven over the millennia of their superiority in many ways of these natural/traditional methods, so in that regard your observations are very accurate.

"Trenching" is actually part of the "Raised Earth Foundation" as well, and these trenches and other "drain channels" are common to all these similar and related systems...

In a few word...it is all about..."drainage," and natural water management and mitigation.

If we were "only just" creating a trench under a wall (or anything else) that had not design or intended plan, then indeed this could be a perfect vehicle for water to infiltrate and move up into a structure, instead of away from it...However, these trenches and other drain systems are specifically designed and laid out to do the exact opposite and working in concert with the "roof diaphragms" drainage design, the water around and coming from overhead, is effectively channeled (and can be also store) in and/or away from the architecture itself.

Understanding this is actually one of the reasons I do not employ "gutters" in most (not all) designs. Water management is best done in a subterranean fashion, and/or stored there as well, and/or in plant tissues meant to manage and mitigate water.

What if there is a lot more water than the pipe is able to handle?Surely that is not the best way to do it? Wouldn't it be better to have that drainage trench as far from the wall as possible?

Think of the roof as an umbrella, and the podii as a great pair of boots. For this umbrella/boot combo to work well, (and to keep you from standing in mud) we need a series of either trenches and/or "drainage pads" that all work in concert to drain water where we want it to go, and not go.

Pipes, whether modern plastic (which have merit in many ways) or traditional clay/stone/brick subterranean culvert system are not meant to handle all flows that are possible but to expedite the "average amount" for a given design in an expedient manner. This conversation would rapidly cause eyes to glaze over for most readers if I went into the greater details of "materials angle of repose," "drain rates" "flow capacities" and other such things that go into good (and proper) foundation design...

This is why many like myself in the professional sector become a tad concerned when folks write of speak so "generically" about building a "natural house." It can be very easy, yet there are many factors that should be better understood and planned out...not just done a certain way because of an image in a book illustrates it...Some books are just plain inaccurate, while others are just not detailed enough and too often folks are "mis interpreting" what they may think they understand....Which isn't an author's fault, and why most (if not all) of these books have a disclaimer somewhere in the beginning (or ending) of them.

I would have favoured open drainage trenches filled with gravel, or just open so the water moves.

This can work very well also, yet in some areas it also cause too rapid of evaporation of water than needs to be conserved and stored. Open drainage can also be an issue if near a house in raising the ambient marco humidity levels around the architecture. It can also be a breading ground for many biting insects if not part of a really well design water feature within the landscape and a balance ecosystem to balance it out. All in all, under ground is much better than above, unless very well designed and planned out. Open channels also have a very nasty habit of going through the natural process of "succession" just like any open body of water....In other words...they natural get clog faster than drainage underground that is protected and process "cleanouts" that also must be maintained just like gutters on a roof (just not as often.)

Could you use like a podi foundation with a dry riverbed drain around the outside channelling water into a rain garden?

This can indeed be part of some designs...in some environmental types and building sites, while in others, or with certain designs, it may not be the most prudent option.

Hope that helped and address in detail some of your points.

Regards,

j

Thanks for humouring me Jay and explaining everything so thoroughly! I am still learning a lot about building and focussing on learning as much as I can about good design before we make a start building. I really appreciate you explaining so much. You have deepened my understanding greatly.

One thing I think I haven't fully understood about the raised earth foundation is how the earth can still act as a thermal bank without simply pulling heat out of the house through the floor. Something like the korean Ondol system would maintain and radiate heat as it is simply pre-modern (and very cool) underfloor heating, but it would seem that the typical raised earth foundation would leach heat unless it were somehow insulated. Likely I have misunderstood, as I do not mean to suggest that the japanese have spent millennia walking around on cold floors but I don't understand the mechanisms at play very well.

I also wonder about certain additions such as the japanese engawa (?), or wrap-around porch. It seems that this is an easy way to co-mingle the living space with the outdoors and also provide a successful method for extending the roof overhangs. Why then, are these porches not integrated into the raised earth foundation, but instead usually set out some distance on top of posts and plinths? My guess would be is that the house can then shed the water effectively many feet away from the foundation itself.

Fianou Oanyi wrote:Thanks for humouring me Jay and explaining everything so thoroughly!

Hi Fianou,

I truly enjoy questions/thoughts from folks like yourself...

These types of query not only help you, but other readers having the same thoughts, and conclusions.

Thanks for taking the time to read and think about all this and natural building...

Kieran Chapman wrote:One thing I think I haven't fully understood about the raised earth foundation is how the earth can still act as a thermal bank without simply pulling heat out of the house through the floor. Something like the korean Ondol system would maintain and radiate heat as it is simply pre-modern (and very cool) underfloor heating, but it would seem that the typical raised earth foundation would leach heat unless it were somehow insulated. Likely I have misunderstood, as I do not mean to suggest that the japanese have spent millennia walking around on cold floors but I don't understand the mechanisms at play very well....

Hello Kieran,

Having spoken with, followed, read, and listened to countless Building Scientist and other PE over the years regarding the world of architecture, I can say that most will admit that "thermal dynamics" of architecture is one of the poorest understood and often negatively conflated by alleged "building and construction experts and industries."

This is particularly true for "U Factor" and its potential values. The best way to think about it...in the most generic of terms...is one a mass object (in this case the foundation itself) is brought to a certain temperature, it has a tendency to store this (flywheel effect at work.)

So in the summer time, the "coolness" of this mass has a strong effect at keeping a structure comfortable, if other aspects of the architecture are working in concert together to achieve some form of homeostasis.

In the opposite season this mass has a tendency to store "warmth," as the earth is natural "warmer" (comparatively to winter ambient temperatures) and holds the heat effectively. If you will...this is a form of rudimentary "geothermal" heat storage. There is some loss, but minimal as "heat" tends to rise...not go down. The planet itself "radiates" heat from its core.

One of my rather intense hobbies of the past (don't get to much any more) is "caving." There are all types of caves in the world, with most being "cool" but not cold by any means...Nevertheless there are also "hot caves" that the deeper you go the hotter it gets with some reaching the temperatures of an oven...Our planet is one giant "nuclear fusion reactor" and most folks forget that. We basically are a stone crust wrapped around a little "Sun" at its core. Like all things it has a "life cycle" but it tends to be measured in billions of years, not decades. Along this way, our still young planet is very "alive" in many ways...

Kieran Chapman wrote:I also wonder about certain additions such as the japanese engawa (?), or wrap-around porch. It seems that this is an easy way to co-mingle the living space with the outdoors and also provide a successful method for extending the roof overhangs....

The engawa, as with most veranda, porches and related spaces does indeed lend themselves admirably to "outside living" in all manner and form. I virtually have them on everything I build, as the logic is just too strong to ignore, and does a perfect job of creating the ultimate "umbrella" for our architecture, and healthy living styles.

Kieran Chapman wrote:...Why then, are these porches not integrated into the raised earth foundation, but instead usually set out some distance on top of posts and plinths? My guess would be is that the house can then shed the water effectively many feet away from the foundation itself.

It all depends on the region, culture, and styles.

Some are part of the "Kindan" while others move past it and actually form an "umbrella" that not only covers the house itself but additionally the podii system also. In some forms, the "socle" or "plinth" form the "raising" of the podii, while others may be multi tiered. Even in some French, and of course Greek and old Roman/Italian architectural forms for example, one has to really move way back away from the architecture to really take it all in. At that point one sees that the entire garden, yard and house all sit "raised" off of the natural grade in a crescendo of different levels with the house at the upper tier.

Your "guess" is more than insightful...it is exactly the reason.

The "moder" bad habit of ...."zero entry"...architecture is the poor bastardisation and lack of understanding these systems... Many "raised earth foundations" have "zero entry" architecture. However, it can actually have this convenance in its design because the entire mass of the yard, foundation and structure itself all sit at least a meter usually above indigenous grade of the building site.

I did want to close with an understanding that many "vintage designs" where more "airy" (aka what we would call "drafty") today. This was not from a lack of "understand" about "draft proof" living. Rather from a robustness in our ancestors that most have lost today. I routinely let our home, during certain seasons (fall,spring) lower its ambient temperature into the 5 to 10 °C range. (~40 to 50 °F.) Warming the "body" is much more efficient (and healthy in my view) than trying to "heat or cool" an entire structure.

Some (many?) forms of vintage homes (and living styles) only planned on heating a limited space...not the entire structure. Ondol are a good example as most only heat a raised bed or dias within a single room...not an entire floor of a house, though some did and could. All in all, I feel there is a broad range of understanding (and life alteration) to really embrace "all natural living." I find it to be much healthier, and much easier to maintain, as did, I suppose our ancestors, and it hasn't been until the "softness" of technology and consumerism inundated our lives collectively as a species that we forgot this...

Regards,

j

I saw a great idea in a house once... now unhelpfully I can't remember where to try and find a link/reference, but anyhoo... where they used a bank of glass facing the sun for passive solar gain, with a paved flagstone floor to gather heat, hydronic heating in the house, but also, a big rock. Essentially the house was built around a rock that was used as a bank of thermal mass to both heat and cool the house. In the winter the windows captured the sun and it would hit the floor and the rock and the heat would be stored. In the summer the sun would be higher and would not come in the glass windows and the rock would store the cool. I thought it was a brilliant idea. It took the notion of thermal mass to a whole other level. Plus the bonus was the rock was a stunning feature and gave a great connection to the earth.

@ Jay C. White Cloud and Bill Bradbury - If I remember correctly, both of you have mentioned in passing, basements.
So - aside from Raised Earth Foundations - have you specific threads for natural subterranean foundations?
I haven't done a thorough search yet - there is just sooooo much info in these here parts - I tend to get lost in the dialog.

If you'd prefer to actually answer this question elsewhere - could you take a moment and answer it on my post - New Home Design Challenge(d)?

Another question with respect to foundations in general - since many of the particulars are dependent on the weight of the structure, is there an easy way to calculate the load on the foundation for any specific structure to easily resolve the dimensions of the foundation? Granted - I do understand that the soil type is the other major factor. For my project, some of those details are posted for a specific hypothetical case - no mileage is guaranteed (the extreme version of, your mileage may vary).

Jay C. White Cloud wrote:

I think we can only glean a glimmer of understanding of how many (not all) these people lived in there homes in the past. I think the people of a hundred years ago preferred 72 degrees as much as we do now, and did not tolerate drafts any less than we do today...I could be in error, yet compared to those still living this way and building these structures for themselves, I think I

I know this was written a while ago, but this part caught my eye. I think you are in error here. I think the whole 72/21 thing is a sales gimmick to sell more building supplies/energy and is very new. The idea that there were warm parts of a home is an old and quite common idea in many parts of the world. Most of the time these warm parts were radiating in nature as can be seen from chairs with insulated high backs and curtains around the base. Also look at the standard bed with a frame/canopy/curtains booth/tent surrounding it. Yes people liked to be warm, but the house was not expected to be at any certain air temperature, that is a late 20th century idea that has yet to cover the whole world.

As part of my wofati background study, I looked into "pit houses" native to the part of the world I live in (SW BC Canada). While these were not seen on Vancouver Island where I live now, they were quite common on the mainland where I used to live the interesting thing though, was that in the Hope BC area the pit houses had a fire in them to keep people warm. This is as expected. What was unexpected was that similar pit houses in the Delta BC area did not have fires in them but the young and old still spent their winter in these homes.

Quick note: On Vancouver Island the Long House made of 2inch thick cedar plank often cut from living trees was common. Same people as the mainland but in an earthquake zone.

Two more things to point out. In the late 70s I spent a summer on the lower end of Baffin Island (Frobisher Bay as it was called then). The high temperature was 6C (40ish F) and I wore a jacket of some sort whenever I was outside. However, I was able to observe the children there in bathing suits playing in the sprinkler just the same as children much farther south. Just recently I have been working as a Letter carrier for Canada Post and find it very comfortable to work outside for hours at a time even in wind and rain wearing shorts and a short sleeve shirt. The outside temperature being in the 6C range. The point of all this, is that humans are remarkably adaptive to temperature swings even being fur-less creatures.

Another story from personal experience: My family and I have enjoyed walking on the beach in all kinds of weather including gale force winds and rain. One event in particular comes to mind. There are a lot of logs and sticks on the beach we like (there are less people there) and we had found two big (4foot diam or so) logs at right angle. We decided to build a small hut by stacking small logs against these two log house fashion. However we did not notch the logs so there were 6 inch gaps between them. Our hut ended up about 4 feet high with a 4foot by 5 foot floor size. As I said this was one of those gale winds days (used to be small craft warning) and we were dressed for it. What was interesting to me was that even though these 6inch slots were head on to the wind, the inside of this hut was warm and it felt wind free. I couldn't have been wind free of course but was very welcome.

To people who spend most of their day outside, warm or cool have different meaning from someone sitting watching TV or playing with a computer. We seem to have grown up with the idea that air temperature is important for comfort. I think this idea is in error. Being warm is important, but what that means is somewhat lost to modern man. I think warmth is subjective and we are really unable to measure what warm is with a thermometer. I also think draft or lack thereof, is not that big a part of the picture in how a dwelling feels.

Foundations? What I am saying about foundations is that having something that breaths and allows a draft (probably not as much as one would think) is the right way to build. No concrete needed. Start with large stones and go down towards gravel by the time the foundation is above ground. This will keep the water from wicking up to the wall... From walking in the rain... I find shoes that evacuate moisture well better than rubber boots (which end up wet inside from sweat if nothing else).

My boyfriend and i are also going to try out building some eco houses. If any of you have any advise thats would be great. Here is our kickstarter page if you want to donate or simply tell us what you think !
Thank you
https://www.kickstarter.com/projects/1057204348/eco-friendly-wooden-cob-and-hampcrete-holiday-home

Wow! What a lot of fantastic information! I hope this thread is still active, as I'd love to have some input. I have a small (2 ac) acreage on Vancouver island. The back acre or so is forested, there is a creek that runs through, but a lot of it also is quite marshy. I would like to build a small cabin or studio or whatever you want to call it, out there, as there is abundant wildlife, privacy and it's just a great place to be. I Have found a nice spot that I have been watching through the seasons, and water doesn't ever pool here, though it does in many places around.
Do you think that a raised earth foundation would work here, or do you think it is just to wet?
To clarify, I'm not talking a house with a kitchen or anything, just a cozy spot to be.

I think previous posts here will give plenty of details on how you could make a dry foundation. For just a sitting or tenting spot, as long as your land has stones available you should have no difficulty in making a good base. Depending on whether you want a raised area or an inconspicuous floor, you can start piling stones on the surface, or dig down before starting. Removing soft organic soil before starting will make it easier to get a firm base in any case. If you have no plans for a permanent structure you don't need to worry about frost depth if that is a factor in your climate.

"Raised earth" does not imply a pile of ordinary soil, but rather a mix of materials which resists damp from rising to the top surface, largely by giving it no pathway for getting up there, and allowing what is present to dissipate to the exterior.

I don't get the substance of this thread. Is it merely rejecting "modernity" as symbolized in $20 of poly vapor barrier?

We need more modernity, not less. Only the most upscale residential along with some commercial and industrial applications use air to air heat exchanging ventilation. The rest make it "air-tight" and spend the extra money on size or style (i.e. it is not "normative"). If we want to live in small, sustainable, energy conservative -yet healthy- buildings we should incorporate systems that exchange the heat of outgoing air into the incoming fresh air -to open the window in winter and not suffer heat loss. Just need to power 2 small fan motors, which could be 12 volt. I don't understand why heat-recovery ventilation is not the "normative constructure behavior of modernity." ... nor do I understand arguing about plastic film which merely symbolizes something undesirable. Plastic is an awesome building material for many applications (e.g. plumbing). I regret that because of our "normative" energy gluttony our great, great, great grandchildren will probably be mining our current landfills to recover some recyclable plastic to make their version of Pex.

.

Len Ovens wrote:

Jay C. White Cloud wrote:

I think we can only glean a glimmer of understanding of how many (not all) these people lived in there homes in the past. I think the people of a hundred years ago preferred 72 degrees as much as we do now, and did not tolerate drafts any less than we do today...I could be in error, yet compared to those still living this way and building these structures for themselves, I think I

I know this was written a while ago, but this part caught my eye. I think you are in error here. I think the whole 72/21 thing is a sales gimmick to sell more building supplies/energy and is very new. The idea that there were warm parts of a home is an old and quite common idea in many parts of the world. Most of the time these warm parts were radiating in nature as can be seen from chairs with insulated high backs and curtains around the base. Also look at the standard bed with a frame/canopy/curtains booth/tent surrounding it. Yes people liked to be warm, but the house was not expected to be at any certain air temperature, that is a late 20th century idea that has yet to cover the whole world.

(...)

Just like task lighting, task heating should be a common principle in housing design. A warm floor, couch, shower dressing area and toilet seat are really all that is required IMO. Let the rest of the house be what it is receiving whatever tramp heat from these favored "hot spots."


.

I've read this thread through 2-3 times because I'm captivated by the idea of long-term durable and dry foundations made with natural and on-site materials and am trying to better understand the concept.

What could have helped me understand the subject better is a diagram or two for specific contexts.  So I made an attempt.  The context is 4’ frost depth, northeast USA, varying soil types, water table below frost depth. Please critique, letting me know if I'm spot on or way off. 

Please note that there are three questions in the image.

I forgot to illustrate that the foundation would not be a bowl that would hold water, but would have drainage ability, as applicable to the site.

Lastly, for now: should the foundation infill always be separated (with cloth, etc) from the surrounding undisturbed soil to prevent 'silting in'?

Hello,

I'm new to this site.  I'm responding to T.S. Moss' post and sketch.

Q: Should there be a layer of clay covering it all?
A: Clay has a relatively large capacity to absorb moisture and swell, and an equal capacity to expel moisture and shrink.  A volume of clay placed as you indicate--as a cap over fill*--would not likely have an appreciable effect on moisture intrusion into the fill; however, because of the swell/shrink capacity mentioned above, it would likely negatively affect the plinth stones by raising and lowering them.
* Gravel is a material which is suitable for consolidation through vibration and pressure. Consolidated fill is usually suitable for structural bearing if properly designed.  Small stones do not consolidate.

Q: Should there be layers of clay alternating with gravel, stone layers?
A: No--for the same reasons outlined above.

Q:How does any of this design change, if at all, due to the surrounding soil being sand, silt or clay?  
A: Depending on its characteristics, the surrounding soil mechanics would have an appreciable effect on the type of foundation illustrated.  There's not enough information regarding the soils.  For example, depending on the shape characteristics of sand, it can be consolidated or not: round grains will not consolidate, irregular (called sharp) grains will consolidate.  If there is organic matter present in the silt mentioned, it will continue to decay and the volume will lose mass.  Clay will shrink and swell.

Thanks for adding your knowledge, Brett. I wonder though, how what you wrote about clay can be resolved with what the O.P. Jay C. White Cloud wrote earlier about clay layers and packing clay as part of R.E.F.s.

However, before you answer that, please note that I think I didn't help myself by adding in specific, or technical, questions to my posting; this is just continuing to confuse me.  I feel like there's a lot of individual aspects of R.E.F.s debated here, but I haven't been able to put it all together  enough mentally to feel confident in creating a long-lasting R.E.F. myself (vernacularly).

I see so often in articles about more modern & conventional construction cutaway or flat diagrams that make clear what even pages of writing fall short of (at least for my mind).  People may be debating features of said diagram in the comments of an article, but at least readers can mentally comprehend a big-picture visual to give grounding to the debate about technicalities and to see a functioning design in at least one specific context.  A picture is worth a thousand words, so to speak.

I hope someone who feels they have a sufficient understanding of a raised earth foundation that would be (or has been) successfully long-lasting in a humid temperature climate (e.g., northern Japan, Korea, northeast USA) would take the time to sketch a diagram, maybe like I did.  Or short of that, attempt to fully describe one feature by feature.