Natural building on a hill (slope)

Hi everyone.

Before starting this, i will apologize up front for not being terribly clear.
This happens to me sometimes (often ?) since i'm an engineer by training/inclination and you know the saying ...

Anyway, this is it:
Since i got "The Bug" some years ago i managed to buy a piece of land on a hill.
Pretty irregular shape, agricultural land, with many slopes on different directions.
Largest one is at the front of the property, it goes for cca. 150m at a 15-18% pitch (haven't managed to measure it actually).
The slope is south oriented (one of the reasons why i bought the land).

I would (eventually) like to build "something" and "live" there, from the land.
I might reach this goal by the time i retire but hopefully much earlier.
Anyway, i studied a lot (both good and bad as you will observe soon).

The main issue with agricultural land over here is that you are NOT allowed to build on it.
That is except if the building's sole purpose is agricultural.
Or maybe if you know half of the county's government people and have a lot of $$$ (both are not applicable to me).

So, whatever i build will have to be "agricultural".
This is something that i want anyway so, good to go.
But how can you "make" such a contraption anyway ?
Well, first of all it must NEVER ... EVER ... come close to looking like a HOUSE.
This is perfect, since don't like much of the "modern" looking houses (traditional ones maybe).
So a barn ?
Not really.

One answer would be "traditional" building (pertaining to the materials and construction "technology").
That means cob, rammed earth, straw bale, some wood, etc.
These are highly disregarded around here, concrete/brick and it's disciples being the norm.
But just material usage might not do.
My conclusion that what will do completely would be some form of greenhouse.
I've read the "suck factor" thread and done the math. I actually agree with both sides pro/contra.

Ok, so this is the background.
I have attached a drawing (by hand) on what i was thinking.
To make the message short, i will continue with a reply.

Since i am an engineer (told you so), my first thing was "standard" materials.
That means OPC, EPS, glass wool and all that jazz.
All these must be closely coupled with "active" systems in the mechanical and electronic dept. (think of mechanical ventilation and co.).
This is something i do naturally since i was bred like this.
Natural building is NOT natural for me but i'm beginning to get the hang of it.

So i finally left some of the conventional materials/technics behind (some of the above ones).
The others i kept since i didn't know any better.
But after reading the "raised earth foundations" and similar threads by J.C. i suddenly got some light bulbs working (a lot of them).
They shed some light on the path i was on (that being that i'm on a wrong one).

So now, between using rocks (hey, i live 30km from a quarry/sand mine) and using "tataki" (thanks for that J.C.) for the floor (instead of OPC concrete) i actually am much closer to the goal.
However, what remains is the larger picture.

Ok, so let's get back to the drawing.
What i envisioned was a sort of house attached greenhouse.
That is loosely said because they share just one surface (not wall). For the house it's the southern surface, for the GH it's the northern surface.
The access can be done by some type of door, usually closed.
I've read what has been said about these kind of structures and, for the first time, i am willing to let them go if i realize they are too much trouble.

Since the land is sloped, i thought of doing a small terrace or even a sunken terrace (as shown on the drawing).
That would be the GH. I would like to put some trees there.
It only needs to go from z6b/7 to z8/8b.

The "house" will go on the north side.
Original thought was SB but thick rammed earth might be a better match (i have a lot of earth).
The north part and some of the E-W will be berned by the natural land slope and will have less temperature gradient year round than the surrounding air.
Drainage must be excellent (see the gravel).
I don't know about insulation. EPS on the north wall does not sound right due to condensation possibility and rodents. Other type i don't know.
I helped my godchildren build a SB house an they used EPS and glass wool in some spaces temporary.
Mice loved the EPS/wool and almost completely destroyed them by doing tunnels inside but left the bales intact ... completely unexpected behavior.
Now this was protected EPS/wool.
This i got confirmed from several other people (that rodents LOOOVE EPS/glass wool).

So, the GH side of things has issues, i know (materials used, lifetime, maintenance, over/heating, ventilation, humidity, etc).
But it might make sense if it will have multiple uses (like a greywater treating facility, etc) and done right.

I have many more to the point questions but i am waiting for comments on the general idea first.
My knowledge and understanding can only increase with them.

Thanks.

I think it looks great! I've been living in houses that are somewhat similar for the past 20 years, with only passive solar heat and no backup heat, during winters that go down to -21C on January nights.

If you want to have some space that won't get overheated on sunny days and wills tay warm enough to sleep in on winter nights, I'd recommend that you use a thermal mass wall between the greenhouse and the hallway, rather than mostly glass. I agree, I love rammed earth, and it's thermally the best in that situation. Straw bale might get problems from humidity, and probably isn't as good for thermal mass as rammed earth or stone or any kind of masonry.

I think you should insulate the northern roof -- in the drawing it looks like you're thinking of a metal sheet or something.

Also consider ways to remove the greenhouse glazing in summer, or to open large portions of it. Overheating can be a problem. If you can avoid overheating, I love the way that a greenhouse attached to my living space heats the house in winter, provides a green space when everything is dormant outside, and then we remove the greenhouse for the summer and the growing things are open to the sky. It works really well for us. We grow grapes in there, which are just a little too tender to grow outdoors, several perennial flowers which bloom in the greenhouse much earlier than outdoors, and we start all our vegetable transplants, and also we grow some annuals in the greenhouse both summer and winter.

We have our houses bermed into a south-facing slope so that the northern walls are not exposed to the outdoors. I suppose a thick thermal mass wall with insulation outside of it would provide an even warmer living space, but currently the houses we've been living in simply have a stone retaining wall into the hill on the north. The north wall registers about 10 - 14C in winter with one of those infrared thermometers, which I guess is not ideal for a passive solar heated house, but we wear sweaters and sometimes hats and we like it.

Thank you for the input.

I haven't put much details in the drawing.
I thought i might better start with the bigger picture.

The GH:
- i imagined a SHCS but the tubing/fans/electricity has a sharp price and does not last forever ...
- whatever heat the SHCS can't take, windows will (automatic of one form or another)

The surface between GH and building must have some glass. Some or most, depends on actual requirements (this i will ponder later).
The "house" may sit a lot higher than the GH so laying massive stones or plain rammed earth at this place might be better, depends on many factors.

The northern roof must be insulated (with what ?).
I have not put that on the drawing because it's a detail.

I would love to have the greenhouse detachable for 2 reasons:
- save some sun burns (if using plastic material) during summer which prolongs material life;
- expose the plants to the real world.

My main concern is with the amount of labor needed to remove/rebuild the glazing.
I don't want PE film since it breaks down very fast.
2 wall PC is good priced but does have a 10-15 year warranty. Panels are large, how do one moves them ? Movable framing ? Complicated, nut impossible but probably too much trouble.
Glass is good, does not break down by sun, just by hail. Enough to have 1 ocurence. Also heavy but not a problem per se since the supporting structure must resist many times more the snow load (by the codes).

We use plastic film that is UV resistant and it lasts a good 5 to 7 years. It would last longer if we didn't have such ferocious wind here, and feral dogs tearing in at the corners.

It does take a team of several people to roll it down once in autumn and roll it up in spring. We cover it with cloth and tie the roll in place along the edge of the roof.

Hello Ionel...

So, whatever i build will have to be "agricultural". This is something that i want anyway so, good to go. But how can you "make" such a contraption anyway ? Well, first of all it must NEVER ... EVER ... come close to looking like a HOUSE. This is perfect, since don't like much of the "modern" looking houses (traditional ones maybe).

So a barn ?

Not really.

Not really??

Barns are probably and absolutely the best architecture to first stick on a peace of land just about anywhere in the world...They have been with us since we first started sticking seeds in the ground and keeping animals for more than just meat alone. This millenia old wisdom should not be ignored. Greenhouses are great as greenhouses, but have there limitations as "permanent" living spaces. Barns service such a broad range of uses that little can match them. Build a vernacular barn for the region you are in (I can think of a half dozen styles from Eastern Europe alone as my father was Roma) that would melt into the Romaine landscape like it had always been there. Placing a "transient" and/or seasonal, "Greentwo" as I like to call them as Rebecca has suggested is a brilliant application to this type of building, or better, design a traditional barn and really nice naturally built stone, earth and timber glass "permanent" green house and attach the two structures with a functional climate controlling "air lock" structure between the two forms of architecture.

Either way both of these go well on the land, attract little attention. People have live in barns with their animals (still do) for thousands of years...

One answer would be "traditional" building (pertaining to the materials and construction "technology"). That means cob, rammed earth, straw bale, some wood, etc.

Yes...yes it would very much!!

I've read the "suck factor" thread and done the math. I actually agree with both sides pro/contra.

Cons (on average for many builds) far out way the pros if speaking of "permanent" attached greenhouse/solarium in the "live in" green house concept.

Since i am an engineer (told you so), my first thing was "standard" materials. That means OPC, EPS, glass wool and all that jazz. But after reading the "raised earth foundations" and similar threads by J.C. i suddenly got some light bulbs working (a lot of them). They shed some light on the path i was on (that being that i'm on a wrong one).

Glad you got some use and a paradigm shift in thinking from that post...that was my goal...

In reference to "modern materials path" ...I would suggest not the "wrong one" per se...just not really as logical as most modern architects, PE, and builders would have us believe all these modern materials have to give us...which is very little. Actually, still today, the most enduring forms of all our "modern materials" are actually the ones built millenia ago....

The oldest (and most enduring still today) "cements" are all over 2000 years old. We are just beginning to unravel that mystery, and by the younger engineer types that are taking a step back like you are and asking:

"why re-invent the wheel...when we haven't even built a wheel as good as our grandparents had? Nor do we even understand half of what our grand parents knew. "

I say be inventive...but truly understand everything you can about what you are trying to invent.

I like the old adage...if it ain't broke...don't fix it!! I also live by what I was taught by my teachers/mentors..."If you don't understand something 100%...DON'T have the hubris to think you can make it better or improve on it....However, if you have mastered a craft then be creative with it..."

So now, between using rocks (hey, i live 30km from a quarry/sand mine) and using "tataki" (thanks for that J.C.) for the floor (instead of OPC concrete) i actually am much closer to the goal.
However, what remains is the larger picture.

Great!! I promise...the "large picture" will reveal itself if you take your time and plan well, listen better to the building site and what it is telling you and the natural world around it. That is what our forbears had (still have) over most modern humans...

Ok, so let's get back to the drawing. What i envisioned was a sort of house attached greenhouse. The access can be done by some type of door, usually closed. I've read what has been said about these kind of structures and, for the first time, i am willing to let them go if i realize they are too much trouble.

Build a barn...then a green house...or a "greentwo" on the barn if that appeals to your personal sensibilities and logistics/ergonomics at the building site.

Since the land is sloped, i thought of doing a small terrace or even a sunken terrace (as shown on the drawing).

I like the drawing a great deal, yet would shift the design to reflect a regional vernacular style of structure more.

The "house" will go on the north side. Original thought was SB but thick rammed earth might be a better match (i have a lot of earth).

If you have clay and you have straw available (not hay) then combine the two materials to work in concert with each other. SB is great, but straw clay slip is presenting as much more applicable in a much broader range of biome type and also has a much longer empirical history in application as a form of "insulative cobb," which has been practice for millenia.

Stay away from foams of any kind if at all possible. Mineral wool can give high insulative properties and facilitate a faster build if that is require for a living space. This can either be removed in the future and or encapsulated with another breathable material like straw clay slip, Kubbhus infill methods or related thermal mass modalities.

Mice loved the EPS/wool and almost completely destroyed them by doing tunnels inside but left the bales intact ... completely unexpected behavior.
Now this was protected EPS/wool.
This i got confirmed from several other people (that rodents LOOOVE EPS/glass wool).

Glad to see someone else publishing this type of info. I have been warning folks about this issue for decades yet few have listened to there own chagrin.

If I have missed any specific observations or questions just give them to me in bullet form and I will do my best to address each one.

Bottom line...go vernacular and you will be pleased both in aesthetic form and tangible "long term" function....

Regards,

j

Thank you all for answering.

Jay C.,
Regarding the barn thingy, i must explain where i come from.
The barn, as was known thruout history over here, is becoming extinct.
It's architecture and construction tipology is considered deprecated.
More "modern" styles are encouraged but modern man's lifestyle does not require anymore such a structure.

I do remember my grandparent's barn and the other villagers who had one (these were built more than 60 years ago).
I can't really say anything about the architecture since i don't think they had a coherent one ...
But i do know about the construction techiques used.
Put together some mud, wood and straw and there you have it (some also incorporated small parts of concrete as it was new and shiny then). No prom queen on the beauty side but who cares, right ?
The thing's purpose was to keep rain and strong winds outside.
Sometimes rodents were kept out with limited success.

If you ask about the housing architetcture, there are plenty of examples i have.

So, there are probably worthy barns still around somewhere, i just happened to not see any.
Google is of no help since my people don't like sharing too much (worthy info) on the internet ...
If you do have more info about this kind of vernacular structure from this area, please share.

I like the drawing a great deal, yet would shift the design to reflect a regional vernacular style of structure more.

Care to shed some more light on this one ?
I'm having a little trouble picturing it ...

Regarding material use i do have some experience wit cob, stone and straw bale.
The straw clay slip i know is good but i lack one important info:
what wall thickness can it be realised, how tall can a course be layed and how long will it take to dry.
Alternatively, could a rammed earth/clay straw slip sandwich be made or it's not justified ?

Hello Ionel,

I am actually excited to read your posts because, as I wrote before, my father's family heritage is dotted with Roma culture and ancestors that come from your regions Carpathian Mountains and that of Southern Poland into Germany.

Ionel wrote:Regarding the barn thingy, i must explain where i come from. The barn, as was known thruout history over here, is becoming extinct. It's architecture and construction tipology is considered deprecated. More "modern" styles are encouraged but modern man's lifestyle does not require anymore such a structure.

Yes, many allegedly "modern cultures" (??) do have such dim views of those things that came before them, be it traditional farming methods or the structures they lived in and used for other purposes. This ignorance of the past is both unfortunate and obtuse in view, as vernacular architectural forms are anything but deprecated. I think that those that take a view that historical vernacular archetypes and their many typologies as deplorable only reflect a lack of knowledge or shallow understanding of such structures. These structures have the merit of proven history, sustainability, and durable use, while modern forms are but a pale reflection of these much grander heritage form. Modern builders only seem to reflect impatience and lack of understanding of history and the natural world around them.

As for the Barns of your region (and Europe in general) becoming "extinct" that is an academic debate we probably should not enter into...

I know of many that are anything but "extinct" or even close to be even uncommon in some areas. I know of modern Timberwrights of several regions that are still maintaining and building contemporary version of these many styles. It is difficult to ignore this wisdom in both design and function. Many of this region's forms are much older than just 60 years, and unlike many here in North America that are considered "young" by European standards at only 150 to 300 years of age...you can find barns in Europe over 800 years of durable service.

Ionel wrote:I do remember my grandparent's barn and the other villagers who had one (these were built more than 60 years ago). I can't really say anything about the architecture since i don't think they had a coherent one ... Put together some mud, wood and straw and there you have it (some also incorporated small parts of concrete as it was new and shiny then). No prom queen on the beauty side but who cares, right ?

I am afraid (I don't mean to correct or criticize your view...) however to state that these vernacular forms didn't have a "coherent" form, does not reflect the rich heritage, nor brilliant styles that exist through this region, which is very much part of my own very mix heritage. I do not presume to speak to what structures you saw or "think" you understand that was just, "Put together" with "some mud, wood and straw," but I would have to strongly suggest...respectfully...your comments above do not reflect any knowledge at all about how they are constructed. Not at least in the true vernacular forms of this extremely rich and diverse region that would be Romania.

Ionel wrote:Google is of no help since my people don't like sharing too much (worthy info) on the internet ...Care to shed some more light on this one ? I'm having a little trouble picturing it ...

I would suggest that it may be how your research is conducted, the mindset you hold onto behind it, and the sources you are looking through to find information. I am here in Vermont, and have little issue finding contacts or resources that document your many styles of building. I grant that I have been studying vernacular forms of Eastern Europe, Middle East and Asia for the last 30 years, but with just some very basic quick checks of my own records and a fast "Googling" to search topics, I found a rather extensive list of several forms I am familiar with...I am sure there are even more, but can talk you through the basics of each one of those listed below. I am more than willing to share as much as I know, and assist in any way I can building more appropriately a strucuture like you have suggested interest in that reflects a more sustainable and proven formate in design and history.

Alba Regional Architectrue

Bran Vernacular Architecture

Maramures Architecture

Sălciua Architecture

Arad Architecture

Măldăreşti Architecture

Curtişoara Architecture

Campu lui Neag Architecture

Bihar Architecture

Chiojdu Architecture

Moişeni Architecture

Ionel wrote:Regarding material use i do have some experience wit cob, stone and straw bale. The straw clay slip i know is good but i lack one important info: what wall thickness can it be realised, how tall can a course be layed and how long will it take to dry. Alternatively, could a rammed earth/clay straw slip sandwich be made or it's not justified ?

Height with "straw clay slip" is only limited by the timber frame structure it is placed into. Wall thickness can be as great as required to achieve the desired efficiency goal one wishes to obtain. "Sandwiched" and related multi stratum design matrix with natural materials mixing both thermal mass and insulative forms are all applicable to vernacular design systems of which there are many heritage forms.

I am afraid (I don't mean to correct or criticize your view...) however to state that these vernacular forms didn't have a "coherent" form, does not reflect the rich heritage, nor brilliant styles that exist through this region, which is very much part of my own very mix heritage. I do not presume to speak to what structures you saw or "think" you understand that was just, "Put together" with "some mud, wood and straw," but I would have to strongly suggest...respectfully...your comments above do not reflect any knowledge at all about how they are constructed. Not at least in the true vernacular forms of this extremely rich and diverse region that would be Romania.

I agree with you.
I only said i have little direct experience with them.
What i remembered is from an area of the country where living was not easy and the modernity virus was very strong even 60 years ago.
That's why there was a mix of vernacular and "modern" styles and materials but the emphasis was on functional since life was hard.
And even there people were encouraged to live modernity as was back then.
Settlements who were in the planes were particularly affected by this, less so those in the mountain areas, especially up north.
This, after all, was state policy, forced and criminal but those were the times.

One other aspect is the actual word BARN.
This has so many facets but english has only 1 word ...
We do have many words here for such a structure, depending on it's purpose.
Purposes are keeping crops over time, keeping animals, keeping tools, etc.
This is for the case when the structures were standalone which they were many times.
But just as often there was no clear separation between house/animal shelter/crop keeper since one structure performed all these functions and more.

What i was talking about were mainly the standalone structures that only took one function or maybe more but did not involve actual people living inside.
These i had little success finding.
One example of the kind i do remember is this one.

On the other hand, as i said earlier, if actual living spaces are present, then there are myriads of examples.
The area i was talking previously is in the southern part of the country and if the separate barn structures were perhaps too functional to be pretty, the houses were not.
The architecture was clear and as old as history even with that modernity breath in the air.
The first (and permanent) impression of these houses (i will use this term) was : restful and timeless (as Christopher Alexander put it).

This impression is the same as for the housing in my current region which is the westernmost part of the country.
Suprisingly, or not, my land is in the middle of "old country" that still heavily possesses these buildings.
Even tho the architecture is quite different, the feeling is the same.
This area was under Austro-Hungarian empire rule for a long time.
The local vernacular styles and even the actual people were considered sub par subspecies evenly.
Therefore a major colonist movement was started and new settlements produced.
Architectual style was german and even today, many places have the original german names.
My land sits at the middle of two small villages, Charlottenburg and Altringen.

So, even if you can see the violent assault of modernity, the actual timeless feeling of these places is kept also in the old to very old housing.

So, to summarize:
Some of the links you posted are for architecture styles of my childhood (south).
The vernacular (german actually) local architecture is like this.
A little bit more sober than our own but still in touch with reality.


I will thoroughly analyze every bit of imagery i have and extract a common pattern even if i actually know/feel most of it already (it's in my genes).
This is something that will happen in time.

What i would like to do next is a discussion about the actual building methods implied in realizing the chosen vernacular architecture and it's place in my site.
I will make another post to keep things coherent.

So, regarding materials/methods.

My land is on a hill, therefore sloped.
My engineering self thinks that a construction placed inside the hill, even partially, will benefit from the geothermal energy.
Such a structure will have to cope with some humidity since earth is naturally moist.
A great answer to this issue is the raised earth foundation.
But what about the walls, especially the north one ?
I have extended the foundation thinking to the walls.
If gravel works for the foundation, why nor for the walls ?
That's why i have added the gravel between the northern wall and the earth.

I now battle with two sides of a coin.
Mass and insulation.
I need and want mass and i know it works differently than one would imagine (better).
I still think a little insulation can help.
Here the clay straw slip has monumental advantages (or so i imagine).

So, considering all the above, i need a way to achieve high mass and some insulation.
High mass is easy. Wall thickness of 0.6 to 1m i am willing to do.
But the insulation i would need some help/guidance.
This has three parts:
- wall insulation (possibly the easiest);
- roof insulation (how ?);
- floor/foundation insulation (a red herring?).

Height with "straw clay slip" is only limited by the timber frame structure it is placed into. Wall thickness can be as great as required to achieve the desired efficiency goal one wishes to obtain. "Sandwiched" and related multi stratum design matrix with natural materials mixing both thermal mass and insulative forms are all applicable to vernacular design systems of which there are many heritage forms.

Can you give some links to the sandwich part that i can study ?
I have an idea of how i can achieve a sandwich between rammed earth/straw clay slip/rammed earth but any other experience is very valued.

(I will combine my response to both your post here...)

Hey Ionel, et al,

Ionel wrote:What i remembered is from an area of the country where living was not easy and the modernity virus was very strong even 60 years ago.

I will do my best to help you protect against this. I REALLY!! understand how strong it is there, because of my professional contacts in the building trades in Russia and Eastern Europe. It goes well beyond the face of logic or good reason, especially when it comes to OPC (ordinary portland cement) and what so many people have been lead to believe, and...believe it blindly. I just was party as a fellow reader to a heated conversation between a Russian General Contractor (RGC) that builds concrete and cement brick infill multi-story structures, and a structural engineer that also has a timber framing background. The SPE (structural professional engineer) tried to explain how weak modern OPC is in the face of time and tectonic activity. The RGC would neither listen to reason of direct examination or empirical history on the subject and basically insisted that living inside concrete structures was the safes, most enduring, economic and comfortable architecture to build...He was alone, as that region is dominated by this trade and mindset. With just that one example of many, I hope I reflected just how much I sympathize with where you are and what many builders will try and tell you, or insist what you build with.

What i remembered is from an area of the country where living was not easy and the modernity virus was very strong even 60 years ago.

One other aspect is the actual word BARN. This has so many facets but english has only 1 word...

Hmmm...

Actually, that isn't quite the case. In general conversation, we may through the word "barn" around in many generic and non specific ways. Three are even regional habits of this. However, if you as folks that even understand them a little bit from particular region, you will receive much more than just the single word barn, as this is only part of the term. For example we have:

Bank Barn
Millers Barn
Gambrel Barn
Mills
Granaries
Tobacco Barns
Dutch Barns
English Tieing Barns
Monitor Barns
Pent Barns
Stone Enders
Crib Barn
Dog Trot
Cantilever Barn

And this list continues into regional variants of each of these...

What i was talking about were mainly the standalone structures that only took one function or maybe more but did not involve actual people living inside. These i had little success finding. One example of the kind i do remember is this one.

The link didn't seem to work as intended yet I think I fixed it and there are examples of ethnographic monuments in certain rural areas, yet many are under threat of neglect, which is sad.

Ionel wrote:My land sits at the middle of two small villages, Charlottenburg and Altringen. So, even if you can see the violent assault of modernity, the actual timeless feeling of these places is kept also in the old to very old housing.

That is a beautiful region and the "circular layout of Charlottenburg is stunning and very interesting. I am glad you are in a region that is maintaining this level of respect and understanding for such vernacular structures. I took a "virtual tour" between this two villages this morning, and the views are stunning and remind me of much when I was last in that region. You are blessed to live in such a stunning place...

In your second example, the structures are more "lime washed" and or "lime rendered" which did take place in other regions that lime kilns became more prevalent. These do have there own level of charm. They also led to a bit of confusion as layfolk thought OPC buildings and lime based washes and renders to be the same thing, just one old and the other a newer from. Many still believe this today, and why many old structures are decaying so rapidly, as they had there old lime and cobb materials replaced with OPC

Ionel wrote:My land is on a hill, therefore sloped. My engineering self thinks that a construction placed inside the hill, even partially, will benefit from the geothermal energy.

Agreed, and there are many applicable vernacular styles to this logic. "Bank Barns" is a very generic term used for many examples of this around the globe that have been use for both "just barns" or "barns and/or homes" combined. We have converted a number of these into houses over the years, or built new versions of them.

Such a structure will have to cope with some humidity since earth is naturally moist.

Not necessarily. This is an often repeated misconception about these structures and what some may present like yet this "moisture" is usually the result of opc renders, bad or poorly maintained drainage and structural neglect. I have been inside Mill Barns that sit in a body of water like the stream flowing past that runs the mill turbine, and even below water level, the structure is anything but damp. The principles suggested in Raised Earth Foundations apply above grade, as well as, below grade foundation applications.

Ionel wrote:But what about the walls, especially the north one ? I have extended the foundation thinking to the walls. If gravel works for the foundation, why nor for the walls ? That's why i have added the gravel between the northern wall and the earth.

The walls can be stone if you have them, or some type of gabion system if you do not. Tires filled with rock are a form of gabion system. So your concept of gravel is perfect...this is normal, common and appropriate "good practice" in all these types of builds. There are some "do's and don'ts" but those are easy to avoid. How the drainage is constructed, the size stone, orientation, etc are all the factors that must be looked at. Even the soil types and seasonal hydrology.

Ionel wrote:I now battle with two sides of a coin. Mass and insulation. I need and want mass and i know it works differently than one would imagine (better). I still think a little insulation can help. Here the clay straw slip has monumental advantages (or so i imagine).

This is not only a traditional concept, it is an excellent one. Little is probably less understood and has more "bad science" behind it than the often "industry funded" research into these to forms of insulation architecture which "mass" or "loft" insulation modalities. Each has it pros and cons, and understanding these (as best we are currently able) is the trick. On can be prone draft issues and suffer from interstitial moisture buildup while the other creates thermal bridging challenges and out of synch "flywheel" effects. Homeostasis between the two is the goal, and when achieved "can be" very effective working in concert with one another.

I won't currently design an insulated structure (mass or thermal) that has a wall thinner that 250 mm so you goal of 500 mm to 1 meter is outstanding...

The way I generally consider this (note this is the most basic of generic guidance at this point in your design planning) is if the location is arid and hot I would prefer the thermal mass to the inside of the living space, more of it, and limit "loft insulation" to perhaps only the roof area, and other strategic locations. While in colder climates this is more challenging to get a good balance between the two elements. Loft insulation is more efficient "resister" to cold than is mass alone, yet those issues of interstitial moisture must a constant focus of not allowing them to be trapped in the wall void matrix. So now we move into that actual final building system that is selected, as this has some dictation to what are the most applicable modalities to explore while at the same time considering the ergonomics of the build, the local resources and vernacular archetype/typology for a region.

Ionel wrote:- wall insulation (possibly the easiest)- roof insulation (how ?) floor/foundation insulation (a red herring?).

Wall:

Lets figure out what the wall structure will be first. It will guide this decision. I usually recommend a timber frame structure as where there is forest this is usually the dominant vernacular for walls. As such a mix of minernal wool, straw/wood chip clay slip infill and mass cobbing is recommended.

Roof:

A loft insulation if a more commercial form like mineral wool can be afforded otherwise a natural more loft form like straw bale, or if the framework is robust enough more straw clay slip.

Floors:

These can be a "redherring" as heat goes up more than down and some conservative evidence suggest that loss is broken down (depending on design, convective currents, region and other mitigating circumstances) as 80-15-5 to 70-20-10 or close to those ranges. So the floor is relatively easy to deal with just using good mass forms of insulation, proper drainage and a good umbrella (roof) covering with extended overhangs.

Ionel wrote:Can you give some links to the sandwich part that i can study ?

I would read the following and use the contain information to do additional research. From here more questions are to assuredly arise and I can address those the best I can. These following conversation are full of links and terms to learn about and understand like, wall truss, timber frame, cold roof-rain screening, etc.

Thermal-Mechanical Wall Systems for Timber frames and other structures.

Breathable Walls

Waterproof-breathability

Build Tight...Ventilate Right

Framing for clay slip chip walls

Condensation, and other moisture related challenges in natural building...

best backup heat source

passive solar with hybrid and traditional/natural construction

Regarding the round village, it has a tail now. It looks like a whistle
Mostly vacation houses, questionable architecture ... etc ...
See the attachment.

My land is in red and i don't live there but want to.
I'm next to the local sheepfold (modern building).
The slope is from south (where the road is) to north and also the ear looking part to the right has an eastern slope.

Regarding the strong modernity around, i can tell stories about what our grandchildren built (stone, cob, straw bale hybrid) and how they were received.
I will only mention one thing.
Local construction is pretty much hollow brick encased in concrete (posts and beams).
Our grandchildren's father is a little conservative, that means using plain bricks.
He offered to finance the whole build as long as it was made of brick ...
They refused ...
Now he recognizes what was built is waaaay superior ...

Regarding the word barn, i see the english has more variants but most contain the word barn.
We have completely different words which makes impossible misidentifying the purpose.
The bank barn is very slightly inside the hill.
I would like it to be as much as possible inside for all weather protection.

The link i posted is this.

Regarding moisture, i've read and understood the articles. I was only saying that having an entire 2.5m high wall inside the earth (even with gravel for drainage and aeration) will pose a slightly higher humidity level than the medium air humidity (except when it rains).
I have also experienced mills on creeks to be bone dry.

The walls can be stone if you have them, or some type of gabion system if you do not. Tires filled with rock are a form of gabion system. So your concept of gravel is perfect...this is normal, common and appropriate "good practice" in all these types of builds. There are some "do's and don'ts" but those are easy to avoid. How the drainage is constructed, the size stone, orientation, etc are all the factors that must be looked at. Even the soil types and seasonal hydrology.

The only thing i don't need to haul is clay.
Nevertheless, straw (baled or not) is available locally (pretty much) for modest prices and stone is available via transportation.
I think it costs something around $8-10/ton including transport.
Sand gravel is in the same situation.
I can order any size rock, from pebble to car size, they deliver.
Our grandchildren ordered washing machine sizes and they got it that size give or take.
The rock type is diorite and has a rusty colour.
Local soil is alluvial clay (mostly clay).
Climate is continental temperate with mediteranean influences.
Considered cold climate (zone 6-7) it has some hot summers even a little arid sometimes.
Rain can fall anytime but mostly during spring/autumn.
Annual means are 500-550 mm.


I would prefer rammed earth since i consider it to be better suited to the workforce (me) than cob.
However, since my soil is mostly clay i would need to haul in some sand.

Regarding the sandwich, i imagine something like the attached drawing.
I am still unsure how a bond between the parts is to be made.
As you said, the situation when the dew point temperature is situated at the junction is to be avoided since there is a higher risk of voids being present.
This leads to condensation and all that follows which i want to avoid.

The articles you linked to i have studied more or less as they evolved so i'm pretty familiar with them.
I am doing this reading/studying stuff for some years now but i entered the discussion only because the wife would like to have something built sooner than later.
She does have a point here.

Hello Ionel,

I restored a 140 year old home several years ago that was, as far as I know, a unique pise style building in that it was a rammed earth sandwich as you describe except the builders had left the 4" center open. The 2 4" thick layers of what looked to be lime stabilized rammed earth were tied together with steel masonry ties and finished inside and out with lime plaster, much like what you have drawn here. I think straw/clay would be a great infill for this, but I wonder about getting a permit for such an experimental building. I only say experimental because I have not seen or heard of another like this; that does not mean there isn't someone already doing it.

I would go with A or use a truss for B.

Be sure to test everything first with mock-ups or a shed or something and see how they fare over time.

All Blessings,
Bill

Thanks Bill.

Regarding the permit, you would be surprised what can pass around here for approval ...
But regardless, this will be an agricultural purposed building, that means lower requirements than residential.
This does not mean i won't have higher requirements, just the "code" side has.

Regarding the wall type,
There are 2 simple solutions, each with it's own drawback:
1. Thick mass wall
2. Somewhat thinner insulative wall

1 can be rammed earth but in my cold climate can be a little bit underperformer since insulative capacity is less.
2 can be straw clay, can be a little thinner since it has great insulative capacities but it lacks the huge thermall mass.

Walls of type 1 can be realized as thick as wanted but type 2 not so since the clay has to dry and if the wall is too thick (>12 .. 14") then it will not dry in time resulting in straw rot.

So i still think that marrying 1 and 2 will give excellent results, i just don't know exactly how to do it.
I imagine 20" of rammed earth on the inside + 4" of straw clay or a little more on the outside will do the trick.
I just have no idea how to actually build this, especially regarding gluing the 2 materials together.

I could first build the mass part, put some forms into place, wet the wall to get a better bond and lay down the straw clay yielding a compact sandwich wall.
Or i could first do a thicker straw clay wall and after it dried put down the inside thick rammed earth but i don't know how well will this glue into the straw clay.

More questions than answers ...


PS
The wife says we should first like build a small structure that has pretty much a barn/warehouse function where we can occasionally stay for the weekend, or vacation, when we need to work on the land.
This could give us the opportunity to test everything and see how this works.

Hello Ionel,

The thing with straw/clay is that to get good insulative properties, the mix must have very little clay; therefor little strength, so most designs incorporate a support structure like a Larsen truss and even some bamboo internal cross supports to prevent slumping. That's why I would recommend design 2 with trusses hung from a timber frame, then use ties connected to the inside of the trusses to keep the RE or cob wall tight to the structure. Although the home I mentioned has stood for quite a while, I would stay away from structural insulative core RE and only use this method where t is incorporated into a frame design.

All Blessings,
Bill

I've took data from Doug Piltingsrud's experiments in which the straw clay is 13psf (half straw and half clay by weight).
I have no issues with using a truss, be it Larssen or other type.

What i wonder is the actual implementation.
How thick the RE and how thick the straw clay (with truss) and in what order should they be put up?
From your message i gather the RE is first which can make sense.
Afterwards the trusses get fixed to the RE wall.
Then the straw clay as infill for the trusses.
But considering the straw clay is only exposed for drying to the air on one side, what thickness should it be to avoid being moist for too long ?
On the other hand, the RE wall will at firs absorb some moisture from the straw clay, helping a little.

These are very good questions for me and the answer is not very clear yet.

With that much clay, I would skip the RE and just infill with straw/clay. That much clay will perform as an insulating mass wall without the RE.

I don't have any experience with this, but I think you could use a truss with RE sandwiching a layer of sawdust for the effect that you are after. I would still use trusses for mounting the slip forms and to prevent settling.

Thank you Bill.

I am intrigued by this mass vs insulation strategy.
I gather that to achieve a certain performance one has to either:
1. Build very thick mass walls (>24" ) that offer mass and due to the thickness also some insulation;
2. Build less thick walls (>12" ) that due to the unique combined effect of straw/clay offers enough insulation but also an equivalent thermal mass as above.

I would skip on sawdust since i don't have it available.
I would choose RE since it seems more manageable than cob (to me at least) but i could also skip it since i have to haul in sand.
But clay and straw i have plenty so i think this might just surface as the solution.
I wonder tho if i can manage to build walls thicker than 14" ...

Perhaps we can find someone with more experience in this field.

I actually think that RE is much more difficult to build with than even traditional cobb in my experience and one of the only reasons I haven't been more enthusiastic about RE. I have now seen, and/or been a part of a few of these including an architect's self build. He loved the system and what it offered, but said he would never do it again, compared to other modalities.

I have come to the conclusion as of late that if straw and clay are available, a combination of mass and higher r value insulation is a perfect balance. I personally would have my walls within thermal envelope of exterior walls to a house be of a mass material like dense cobb, wood plank, stone, brick adobe, etc and outer walls of more insinuative form like log, hubbubs, straw clay infill to a timber frame, mineral wool or related system. With this mortality I believe we can achieve a better homeostasis of the better qualities to each system.

Regards,

j

Thank you all.

As of late, the balance was tipping towards straw clay infill in some form of framing, be it larsen truss or something else.
It makes too much sense for the outside walls and for the available materials/workforce.

I did experience cob firsthand and, considering local limitations, i think RE is easier to do but much harder than straw clay.

The straw clay outside walls + mass inside walls (cob/RE/stone) is something beginning to settle in my mind.
Also, a mass(ive), thick floor is something i consider.
I am having a little hard time figuring how to make a structurally sound hybrid.
I will try to put it in a drawing.

My main question is how to secure the interior mass walls to the exterior insulative walls.
I know the exterior walls have a wooden truss system but how can this be safely connected to the mass walls (pink ellipses on the drawing)?
I live in a somewhat seismic active area so good lateral integrity is essential.

Also, another question.
What about the northern wall ?
It will be backfilled with gravel.
I think a good plaster would be lime.
How will the plastered straw clay wall behave in this situation (not exposed directly to air) ?
Of course, the wall will be first left to completely dry, then plaster and only at the very end backfilled with gravel.

And what max wall thickness for the exterior wall (considering it has to dry) ?

As of late, the balance was tipping towards straw clay infill in some form of framing, be it larsen truss or something else. It makes too much sense for the outside walls and for the available materials/workforce.

That sounds promising and like a decision almost made and finalized.

I did experience cob firsthand and, considering local limitations, i think RE is easier to do but much harder than straw clay.

I have experience with all three and would suggest strongly that RE is the hardest by far, then cobb, the straw or woodchip clay type cobbs.

The straw clay outside walls + mass inside walls (cob/RE/stone) is something beginning to settle in my mind. Also, a mass(ive), thick floor is something i consider. I am having a little hard time figuring how to make a structurally sound hybrid.

I am not really sure, at least for me, I would try to re-invent any wheels here creating "hybrides." All these methods come in vernacular versions that only need very little adjustment to work well in concert with each other.

My main question is how to secure the interior mass walls to the exterior insulative walls.

For me, the entire "superstructure" would be a traditional timber frame of some local vernacular style, and the "wall truss" infills" would only need to be structural to themselves and the fenestration within them. The floor could be a monolithic mass of just stone and gravel with "flag stone floor," or a mix of stone, wood and cobb/lime floors.

I know the exterior walls have a wooden truss system but how can this be safely connected to the mass walls (pink ellipses on the drawing)?

By the timber frame as it is done traditionally. Look at these two ancient traditions to get ideas of the hundred of styles there are.

Kath Khuni

Bhatar

I live in a somewhat seismic active area so good lateral integrity is essential.

Considering that Japanese timber framing is subjected to heavy tectonic events on a daily basis in some regions, as are Kath Khuni and Bhatar, this is not an issue.

Also, another question. What about the northern wall ? It will be backfilled with gravel. I think a good plaster would be lime. How will the plastered straw clay wall behave in this situation (not exposed directly to air) ?

If the stone drainage is done properly and well, it should be an issue at all, even if you employed just a cobb mortar for the stone and clay plasters. Lime is of course more durable, but this isn't an issue for rendering walls below grade to the living space side or as an external parging. When backfilling with gravel, I like to see this done in "lifts" as the wall progresses upward with the correct terracing and tying in. Stone work done this way can be very strong. I would also possibly consider a "herringbone" pattern in lieu of the more common "ashlar." Ashlar modalities are not as seismically resistant unless the stone is well fitted and or carved to fit together.

And what max wall thickness for the exterior wall (considering it has to dry) ?

I would have to see better schematics/blue prints and now the other loads this foundation is going to take before I could give german recommendations or ideas about this.

Regards,

j

I am not really sure, at least for me, I would try to re-invent any wheels here creating "hybrides." All these methods come in vernacular versions that only need very little adjustment to work well in concert with each other.

I must not have been clear enough.
Straw-clay is perfect for the exterior walls.
But for interior walls, what is the benefit ?
I don't need insulation on these but i would benefit from mass alone.
So this is what i was calling a "hybrid" - straw-clay on the outside as infill, cob (stone or other mass) on the inside.

The structure it seems to necessitate a timber frame.
The exterior walls are easy, just a truss of some sort fixed to the timber frame and infill with straw-clay.
The interior walls have to be connected to the timber frame too via different means.

The Bhatar/Taq/Dhaji Dewari are simple yet effective methods to build.
The connection between inner and outer walls is straightforward.
But if these walls are different types, then what ?
Or i could just treat them the same regarding the tying method.

And what max wall thickness for the exterior wall (considering it has to dry) ?

I would have to see better schematics/blue prints and now the other loads this foundation is going to take before I could give german recommendations or ideas about this.

I was only referring to the exterior strawclay infill walls.
Most sources say 12" or max 14" due to the drying time.
I saw someone do a 20" wall and had no issues.
I would prefer the 20" thickness or perhaps even a little more.

Hi Ionel,

Straw-clay is perfect for the exterior walls. But for interior walls, what is the benefit ?

Ahhh...I would for interior. I would use a more mass type cobb to store energy and/or fusuma/shoji panel systems or the related depending on design.

So this is what i was calling a "hybrid" - straw-clay on the outside as infill, cob (stone or other mass) on the inside.

Yep...you got it...

And I use the term "hybrid" here loosely and there are many traditional (vernacular) forms that reflect this in there design for given regions/biome types.

The structure it seems to necessitate a timber frame.

For me, and what I have seen and studied...some form of "timber frame" is always the bones of the better designed vernacular structures no matter where I have gone in the world with very little exceptions...unless there just isn't any trees at all for hundreds or thousands of miles...then its textiles, clay and/or stone.

The exterior walls are easy, just a truss of some sort fixed to the timber frame and infill with straw-clay. The interior walls have to be connected to the timber frame too via different means.

I would say you are about 90% there in comprehending these concepts...So...Yes! that is about it.

The Bhatar/Taq/Dhaji Dewari are simple yet effective methods to build. The connection between inner and outer walls is straightforward. But if these walls are different types, then what ?

In their pure form, historically the walls wouldn't be different inside and many didn't have "interior walls" but perhaps a bisecting "load wall." These are the purest forms of vernacular design with the purest use of local materials. Labor intensive but very simplistic, just like so many other forms from the Mountains of Turkey all the way to Hokkaido Japan.

I was only referring to the exterior strawclay infill walls. Most sources say 12" or max 14" due to the drying time. I saw someone do a 20" wall and had no issues. I would prefer the 20" thickness or perhaps even a little more.

I think, with the correct "big picture" design...this is more than achievable...