Construction Earthbags Earthship PAHS

From Earthship to Earthbags

This is a long overdue post and several external movement have prompted me to finally write it.

A while back I wrote how we moved from hemp construction to Earthships. Well the movement continues and we have moved away from Earthships too. This happened gradually and for numerous reasons:

  1. Expansive Clay Soils – we are proud owners of lots of clay-rich soil which expand when wet and contracts when dry. As I was doing research into Earthships specifically and underground houses generally this seemed to be a problem. Expanding clay soil can place tons of pressure on the walls of a house which can cause it to collapse. So for some time I lived with the question is it possible to build an Earthship in expansive clay soils? My conclusion was that the problems was not the clay soil but moisture.
  2. P.A.H.S – As I did more research I started to come across evidence hinting that Earthships do not work well in our climate (moist and cold). Just recently I came across clear evidence of this. I continued my research and was blown away by an old book called Passive Annual Heat Storage. The book introduced a method by which an underground house is insulated with the soil around it, transforming the surrounding soil into a huge heat battery that charges itself during the warm months of the year and discharges during the cold months. The book confirmed my suspicion that the problem with clay soils is indeed moisture and not clay. The “insulation umbrella” concept described in the book (together with other moisture related strategies) provides a solution to keep the clay soils surrounding the house dry – providing a resounding (even if for now theoretical) answer: yes, underground houses can be built in expansive clay soils by keeping moisture away and in doing so neutralizing the “expansive” quality.
  3. Tires in Romania – we could not find a feasible way to get used tires in Romania.

Empowered by the P.A.H.S knowledge I continued my exploration and started looking into earthbags (it’s a terribly designed and uninviting website but has valuable information). I loved the simplicity and ease-of-construction when compared to ramming tires with earth. I would not have considered it a feasible method of underground construction had it not been for the P.A.H.S. method. I do now.

… and so this is the house that we plan to build.

Of Earth Inside the Earth

The house will be completely buried in the ground except for the south-facing aspect. It’s intended location is on gentle south-facing slope. We will excavate for it into the slope.

Most of its walls will be load-bearing earthbag walls. Hopefully our clay-rich soil (that will be excavated to make space for the house) will provide most of the material needed for the earth-mix that will go into the bags. There is no material more local than earth.

The floor will be an earthen floor and the walls will be covered with earthen finishes.

The roof is an as yet unresolved challenge. It too will be covered with earth and will therefore need to carry a very heavy load (current estimation 1.2 tons per square meter). This weight will probably be supported by round timbers though this is not yet final.


We are planning a house that will be ~200sqm. It is designed to spaciously accommodate a small family. It will have a main part and a smaller, attached living space for additional privacy.

P.A.H.S. – 21 Degrees Celsius All Year Long

Thanks to the P.A.H.S. insulation umbrella the house will (after 2 or 3 years of acclimatization) eventually settle on a steady all year-long temperature of 21c. During the warm/hot months excess heat will be stored in the huge earthen thermal battery. During the cold months heat will be drawn from the thermal batter.

This means that we will not need any additional energy input to keep the house warm. Even the water supply that runs under the insulation umbrella arrives at the house at 21c which means that less energy is needed to heat water.

The temperature of the house is a function of how much heat gets into the house (which depends on how much windows it has) and how much it can store (depends on numerous design factors). It is nearly impossible to change the temperature of the house after has been established. Any attempt to heat it will be futile because the energy will be drawn into the thermal battery surrounding it and you would need to invest a huge amount of energy to change that.

Imagine not having to cut down a single tree for heating!?

Rocket Stoves

We do expect to have at least one rocket stove for comfort … to boost the temperature to 23 -24 degrees when we want to … and to heat water during the months when solar-heated hot water is not available.


ventilation is, we’ve come to believe, an important and often missed aspect. The air in the house should be regularly exchanged. Fortunately the P.A.H.S. strategy includes a passive ventilation system (no fans and no electricity to run it) that brings fresh air into the house all year-long at, you guessed it, 21c. The ventilation system also plays a key role in storing excess heat when it is generated (summer) and retrieving it when it is needed (winter).

The trick (and the one challenge that still worries me) is to build the house air-tight. You should not need to open/close windows in this house ever. During the summer months the passive ventilation system will draw hot air out and store the heat in the thermal battery (instead of letting it escape out windows). During the winter months the passive ventilation system will draw air in from the outside, running it through the thermal battery and bring it up to room temperature.

Imagine fresh air during winter at room temperature (and stale air removed) without losing heat to the cold outside!?

Passive Refrigeration

Michael Reynolds in his classic Earthship books points how ridiculous refrigeration can be: we build boxes to keep the cold out, spend energy to get those boxes warm then build smaller boxes inside and spend more energy to keep those boxes cool.

With a slight change in configuration, the same passive ventilation method that is used to regulate the temperature of the house can be used to create a cool space (let cold air in and warm air out). In the Romanian winter that cool is cold enough not just to refrigerate but also to freeze.

Our intention is to build an insulated (from the warmth of the house) space within the house that will harvest winter coolth. That coolth will be stored in water bottles that will freeze. The space will be divided in two. One part will hold a freezer that will be exposed to the natural freezing temperatures. A second part will hold a refrigerator. Both will be unplugged during the winter months. When spring sets on and the ice melts and there isn’t enough coolth they will be plugged back in and run on electricity (which is once again available as the days get longer and the sun shines through).

Photovoltaic Electricity

We would like to be able to live off-the-electric-grid. The first step towards doing that is by drastically reducing consumption:

  1. The house is naturally heated so that no electricity is needed for heating.
  2. Hot water is pre-heated due to the thermal battery, then heated with an efficient rocket stove during winter and with a solar-hot-water panel in spring/summer. Very little electricity needed for pre-heating small quantities of water.
  3. Refrigeration is designed to work on the naturally available coolth of winter when there is very little sunshine to produce electricity.
  4. Large south-facing windows and a one-room-depth house design provides plenty of natural light all year-long.

This leaves us with some lighting and other smaller electronic devices (computers and such). This should enable a photo-voltaic system that will provide all our needs in summer months and most of our needs in winter months.

Attached Greenhouse

The front of the house will be a large greenhouse that will serve multiple functions:

  1. Harvesting heat during winter months.
  2. Extend the growing season.
  3. Growing plants that can not tolerate the harsh winter (lemons? avocados? even bananas?)
  4. Having a pleasant green space to spend time in during the cold winter months.
  5. Consuming grey-water created in the house (this is much easier for us since we use composting toilets and do not have to deal with black-water).
  6. A transition space between the outside and inside (keeping the inside cleaner).

Rainwater Harvesting

For a long time we were faced with a dilemma:

  1. A standard roof that will harvest rainwater for the house but somewhat compromise insulation (all heat inside the house rises) and durability (all mechanical roofs are prone to deterioration and require maintenance).
  2. A living roof that will provide superior insulation and durability but is practically useless for harvesting rainwater (10-15% of a similarly sized regular roof).

After long deliberation we came up with a solution that will provide us the best of both worlds. The house will be built with a living roof (a relatively massive one) that will complete the insulation umbrella.

We will be building a “mirror” structure of the house slightly uphill. This will be a simpler and cheaper structure. It will include a workshop, storage spaces and an open yet sheltered work space for a summer kitchen and other outdoor activities (some of these functions are now unmet or just temporarily resolved). This second structure will have a metal roof for harvesting rainwater that will be stored in an underground cistern that will supply the main house.


None of these technologies are new. All have been implemented in one way or another. We do not yet know of a house that has been built using all these technologies combined in a climate like ours. It has taken almost 3 years of research by trial and error to reach this formula which has the potential to be an affordable, ecological, sustainable and scalable method of construction.

Scalable is an important quality worth explaining. From what we’ve seen most eco-houses fall into one of two groups. One are small hobbit-hole-like homes which are often the result of do-it-yourself builds with natural materials (these do not scale up very well). The other are large and expensive homes that rely on expensive and complicated technologies to achieve an illusion of sustainability (that often ignores their embodied energy and their technological dependence). We are trying to create something that is in between these two worlds. The P.A.H.S. method can be applied to any size home and it is a core component in the overall efficiency of such a house.

This will hopefully be a very-long-term house.

15 replies on “From Earthship to Earthbags”

Hi, I follow your articles and many are very informative to me. I didn’t know about P. A. H. S. book and will be reading it now. I am at the beginning of planning for the family house with directions similar to yours. Also in a similar climate in Slovenia… Great reading and if I come to some concern/skepticism/suggestion, I will spit it out. Keep up the good work, you all and I wish you find the best solution for a comfortable and low impact living!

you talk about 200 sq. meter house. One storey? with earthbags? Will this be like a series of domes or something else?
You probably are already aware about superadobe? Its eartbag, basically. Started by Nader Khalili. I read his book there is some interesting talk about building with unfired clay rich bricks and the firing all the house at once – like a house being a kiln at that moment. This is also interesting, but maybe 200 sq. meters is too much for this…

the current direction is a two level house with one level sitting behind (rather than on top) the first level – so essentially there will be also 200sqm of roof.

domes are out of the question – they are in my opinion not suited for our cold climate – since all the heat rises to the top of the dome (which is great if you are in a hot desert, not so much if you are in a frozen winter).

we are still deliberating overall shape … rounded or straight lines … numerous considerations involved in that decision.

I just recently stumbled upon your website and I found myself in awe. As one who has the same dream – a simpler and more fulfilling personal life in the Romanian countryside – thank you for … validating it 🙂
I truly believe that one needs to get into a certain state of mind to be able to realize what’s really important in life, take a step back, assess, and change. And I truly believe you did it!
We (my husband and I) are – or, at least, we think we are – in the change 🙂 stage. A five year project (being 10,000km away from Romania only adds to the time still to be spent in the North American rat race) of personal change, at the end of which we’ll hopefully achieve at least part of what you’ve already done.

Aside form the struggle to de-clutter out closets and lives, we also – again, just recently – purchased our very own piece of Heaven; somewhere in the Buzaului mountains. This finally gives us the chance to put all our sustainability ideas and knowledge on paper.

Our house will also be very well insulated, energy efficient, and (almost) passive. I would be more than happy to share some of my ideas with you, should you be interested…

In the meantime, I will let others’ experience to take the front seat in this conversation. Did yo know about this?

Wish you both all the best in everything!

Your newest friend 🙂

Thank you for taking the time to visit with us and for leaving your comment.

Thank you also for the link to the AGS house – great to learn that someone has built something like this. We will look into it.

We would love to hear more about your plans, ideas and intentions.
We wish you inspiration on your journey of discovery 🙂

There are lots of useful info in this post! just a simple question: do you happen to know if Romanian code endorses earthbags? are there any knowledgeable architects around to design the technical part?

I know very little about Romanian building codes. Given that I live in a remote part of a village I don’t plan (for now) on engaging any of the formal processes.

If you do live in a place where you have to go through authorization, you will probably need to take either consult with an architect/engineering time which will be able to guide you how to get your plans through and avoid getting into traps.

You will probably also need to take a deep breath and prepare yourself for a journey with the authorities. If you have the capacity for it (patience, money, etc.) then it potentially be a wonderful opportunity to help advance building codes and get the auhorities acquainted with your choices and methods of construction.

I think its useful to remember that building codes are designed to help you and keep you from making stupid and potentially dangerous mistakes. If you are able to hold that in your heart, it may help you nagivate the conversations with the authorities. If you acknowledge to them that you understand and appreciate their job / position / views … you may be met with … understanding and appreciation 🙂

We are kindred spirits. I am a semi-retired Mechanical Engineer. I have reached the same conclusions that you have concerning earthbag earthships and utilizing PAHS. I have been looking at modifying
Owen Gieger’s Solar Pit Plans, which are free… The design satisfies most of your criteria.

I would use Borax Soap treated sawdust as my insulated layer. The Borax will keep away most wood eating pests. Sawdust has the same R-value as Blue Insulating Board, and it is somewhat cheaper.
I would use two layers of clear poly-carbonate corrugated roofing for my glazing with perhaps some welding grade argon gas trapped between them.

I have been studying PAHS in great detail. I have come to some conclusions with that brilliant system (its no wonder John Hait earned his PHD from that work). First there are two variants of his system, either natural convection or forced air. The natural convection system is the most simplistic, but the forced air versions offer enhancement capabilities that were not available in the late 1970’s. One of the minor problems of PAHS was in mid-February to mid-March for houses in Utah & Ontario Canada, the minimum temperature was 62 Deg F/16.7 Deg C, due to lack of stored heat and poor solar incidence. With the forced air variant, one could attach a small air solar collector onto the inlet side of the PAHS system. This would artificially raise the inlet temperature and add more heat to the berm. For every 3 Deg C the average inlet air is heated, it would be equivalent to the house being located ~800 KM further south!

Second since the 1970’s, there are waxes available now that have specific melting temperatures. These waxes start at 67F/19C and there are different ones for every 2 deg F, all the way up to 120F.

The above site describes the way the waxes function. Now suppose that the air solar collector had sufficient ~25 Deg C wax heat storage within the collector. During the day, the wax would melt and at night give its heat back into the inlet air. This solar collector might be 1.5M x 2.5M x 0.5M thick with double glazing, and would be somewhat easy to build. One could easily add in complexity to the solar collector without a lot of cost. The collector could have a small computer(like a Raspberry Pi Zero), that operates insulated shades to maintain the proper desired inlet temperature for the house.

Keep up your great work and I will keep you informed as I start to build my house design,
Bob Cromer

Thank you for your informative comment Bob.

Do you have any links to more information about the forced air variant PAHS?
Is it very different then the core design, or does it simply include fans that are incorporated into the system?
I took great comfort in the all-passive design … knowign that a house could breathe without relying in power.

My attention is now turned towards a small experimental build … an earthbag cellar with very basic ventillation and a partial insulation umbrell.a.
This is both a function we need and a good trial run with some of the underlying methods of construction.

Thank for for the link to Owen’s plans. I have browsed them and will look some more at a later time.

Regarding house design, I haven’t blogged about this yet … but I have spent almost a year reading Christopher Alexander’s “The Nature of Order” and have finally found a view of architecture which answered my question about how to design a house. I had plenty of information abut technologies (earthbags, PAHS, etc.) but very little to go on in terms of how to shape and form a house. This is, I feel, a critical domain I felt was missing … and now I have a direction to go in. You can find a collection of excerpts from Alexander on my personal blog

iamronen, thank you for sharing your researches.

My dream is to build an off grid home in UK. I have studied earthship principles and I was sure this was the answer. There are good points you raise about both difficulty of building with tyres (finding right size tyres, much manual labour required to ram earth into tyres) and the links to evidence that earthships do not perform as well in EU climates. So now I order the PAHS text and hope to make a superior design.

The main daunting aspect of the umbrella design is indeed the roof. Without heavy machinery or a large labour force, raising a heavy duty roof will be very difficult I imagine. With regards domes, they would be structurally the strongest shape to withstand the weight of a burial. Perhaps also you would need load-bearing columns in the centre. It may even be preferable to split the home into 2 or 3 smaller modules (linked by perhaps a greenhouse/corridor), therefore each roof would not need to carry so much weight.

If I may share some other ideas I have seen from someone in US building an earthship out of earthbags: … In this series, he demonstrates a very quick way of laying courses of earthbags using a wooden frame. Truly this seems quickly achievable with only a few people compared to tyres. Also there is a technique for tying the earthbag wall into the berm to make it much stronger than otherwise.

I wish you good fortune in your projects and will continue to read your posts with great interest =)

love the concept and arguments, having read a ton on strawbale to earthbag to earthship, I agree with all that you have said. do you have plans available for what you built?

Hello Scott,

I am glad this post has been useful for you.

A house has not yet been built … currently we are exploring some of the related technologies in the cellar build.

However I can share with you that “planning” is one of the most fascinating subjects I have been exploring. I doubt there will ever be “plans” for the house the way we typically think of plans. I will try to write a bit about the “plans” for the cellar to shed some light o this issue.

There is so much information available about HOW to build but so little about WHAT to build, how to shape and create a space that is alive and can support and nourish life in it. If this interests you, I recommend the work of Christopher Alexander.

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