Pounded Tires vs Poured Cement or CMUs

I know it goes against a core design element, but what do you guys think about cement walls instead of pounded tires?

Three of the major issues I've seen with Earthships are tire off gassing, the amount of energy needed to pound the tires, and issues with trying to get the plans certified in certain cities.

I was thinking a poured cement slab foundation, and either CMU walls filled with cement (CMUs come standard up to 12" thickness), or strictly a poured cement wall without CMUs (and without insulated cement frames). The cement could even be covered with stucco, adobe, or cob.

How efficient at storing thermal mass is a cement wall vs a rammed tire wall? How much of a labor vs money trade off is this, is this prohibitively expensive? Would this be easier to get government approval?

On an aside, I was thinking of a cement slab with tubes connected to a rocket mass heater to create a radient floor heater. Thoughts?

I believe that if you start replacing the thick tires (soil thickness not the tire thickness) then you are moving away from earthship design as I understand it.
As far as the reduction of issues, yes it would work better but it is not serving the function of re-purposing that the earthship was designed to do.
As far as the thermal mass, it would be able to have more thermal energy stored, thicker is better, black it the right color for thermal mass storage.

My understanding of the RMH is that the heat comes through the exaust pipe (flue) so I don't think you could run one RMH to heat an entire floor area, perhaps two to three would be needed.

Redhawk

Thank you for the feedback. I understand the Earthship was all about repurposing and this deviates from that at a benefit of making the rest of the structure possibly more attainable to more people by using more conventional material.

With tires, my understanding is decades ago there was no reuse for them and they were filling landfills, but now tires are being repurposed and finding tires can even be an issue in some areas.

With Earth filled tire walls, they were about 36" in thickness. Any idea how thick a cement wall would need to match the mass of a tire wall? 1:1?

As far as the rocket heater for a radient flooring, I was thinking more of wrapping the liquid filled tubes around the exhaust of the heater.

I'm a historian. My family has been on this continent for 400 years, our family farms have been in this county since before Ohio was a State. We have a museum. One building is 220 yrs. old, one of the looms dates to 1740, a post master's cabinet dates to 1825. On my land I have watched old trees become new soil, corn fields become woods, ponds fill in just from plant matter build up. ---I tend to look at things long term. So, therefore, I really have a problem with using tires for building anything. Tires are made of all sorts of chemicals, all sorts of toxic chemicals. And in time they break down. And those chemicals end up in the water shed and soil. Building with tires might seem like a good idea for making use of something obnoxious, but the long term consequences of such use is even worse. Even if it took a hundred years, or even a thousand, for the tires to decompose, sooner or later they will. So, in my opinion, recycling tires through a recycling center is good, recycling tires by burying them in the Earth, not so much. If you use cement, you're still covering earth, but at least you are not poisoning earth for the next hundreds of years.

I mentioned earlier how cement could be covered, but the more I'm reading into it, the more I like how you can color the cement darker, and how you can use wooden forms to give it rich, organic textures. Granted, the texture in the picture below would be hard to dust.

While I don't personally endorse the earth ship I understand why the designer went the way he did.
My thoughts on the heat sink wall would be more along the repurpose used concrete line.
Ever since Roman times, concrete has been used for building and quite a lot of those buildings are still standing today.
If you used those remains for your wall, you could build faster, and there would be no leaching issues in the future (near or far), plus the ability of heat retention is there and can be increased simply by making the walls thicker.
Should there be concern with stability, just use a thin pour as you build up the wall as you would in a slip form type of building (which could be done easily and you could then have some interesting textures as a bonus).

Redhawk

people become infatuated with the idea of Earthship for a number of reasons.  Most of them can be attributed to our deep subconscious and conscience, which acknowledges that we are one with the planet, part of the problem, and we need to take responsibility for our actions (driving cars, using tires).  

I like Earthships, but they are a heap of a lot of work.  I know this from experience (And we had a hydraulic press for help).  

Recycled or not at some facility, the tires toxic attributes do not lessen their load on our environment, eventually all this crap ends up in the watershed (some sooner than later).  Some tires are recycled into roofing shingles which break down through constant contact with degrading elements like UV, Oxygen, and Water.   In Earthship design, the tires are encased in layers of cob and stucco, so that they are not in contact with UV or oxygen, and are sheltered such that they are not in contact with water.  These are the major causes of degradation to things, and as such an Earthship is truly long term storage for such stuff... until maybe some time in the future when dioxins and other powerful persistent toxins can be broken down properly with future tech.

Urbanite (re-using broken up chunks of concrete), as Bryant suggested, is a great option for the recycler not wanting to use tires.  

Another option would be to use a machine to build walls, like in dam construction, packing a little at a time (like six inches) by tracking over it repeatedly, and then adding another small layer of dirt.  Dams are an incredibly strong structure, withstanding huge forces of water pressure.  Build these as tall as you like and go about your post and beam structure inside and on top.  Make sure to have a big umbrella of plastic to protect your outer walls and good drainage systems in place.  Geoff Lawton suggested this as an alternative to Earthships.

Thick gabion walls offer the benefits of thermal mass, without the enormous work and toxicity of living in a tire dump.

I've only seen one finished earth ship. It has been a colossal failure, in energy wasted,  and in using up a major chunk of a man's life.

Cut off one side wall.
This makes filling them a cinch,and should make compressing the soil inside easier.

Alternatives include earthbags, gabions, blocks of compressed tires,soil cement,slip form stone walls.

A large volume  of concrete would be expensive and takes a lot of fossil fuel to create.

I would like to build a high mass wall using liquid cargo totes. They stack, they are rated for enormous weights and they are cheap.
They are plastic,though one could just use the steel cage as a gabion.

If you follow the design idea, the earthship has the packed tires and then another 4 feet of compacted dirt mass inside of the insulation and under roof.  I can't look up the thermal mass right now, but if you did and then adjusted accordingly you would have the same effect.  It might take 5 or 6 feet of dirt inside the insulation, but that is no cost difference.

Maybe rammed earth walls might be a more environmentally sound and cheaper option compared to cement. This video describes it like a limestone.

Maybe rammed earth walls might be a more environmentally sound and cheaper option  

Rammed Earth is a very effective means of doing this, if you have the right forms and the right soil consistency.  Too much sand, and not enough clay or silt, for instance, and you are going to have issues, but rammed earth can be added to the growing list in this thread.  ...ala William B

Alternatives include earthbags, gabions, blocks of compressed tires,soil cement,slip form stone walls.  

...Another method is cordwood, but it is also concrete intensive, and labor intensive and if burying Earthship style requires careful attention with drainage, and backfill drainage, and super umbrella work over it so that you take any moisture away from your wood.

Thick gabion walls offer the benefits of thermal mass,

I like Dale's gabion cage ideas.  I have often thought, after being introduced to the idea from Dale, that this is the cheapest and fastest way to build structural mass, and it gives a nice outer layer with which to adhere cob or stucco.  In regards to creating dense thermal mass with it, I was thinking that a person could fill the gabions a little slower, mallet packing dirt material around the large stones, or mortaring it with cob, around the outer edges of the gabion especially.  This would ensure that there was more density to gain and retain thermal mass into it's center, rather than just a rock basket, with a lot of air spaces between stones.  

Earthship biotecture actually still uses a lot of concrete in their structures.  I would avoid using concrete as much as possible as it is expensive, and it is resource intensive.    

I've only seen one finished earth ship. It has been a colossal failure, in energy wasted,  and in using up a major chunk of a man's life.  

 This doesn't have to be the case, but you should keep in mind, Jeremy, that in order to build an earthship, or almost any alternative structure, you are going to need help.  Extra labor, volunteer or otherwise, is essential to such endeavors, or it's potentially going to bury you.  

Concrete, while resource and money intensive, is fast.  

Sometimes a guy digs a big pond by hand, and that is cost effective for him, and sometimes he hires a machine and that is cost effective for him.  It's a matter of weighing priorities of time/money/earth care/people care/ goals/ethics  etc.   Permaculturally, people tend to want to regard the ethics of Earth Care and People Care, and as such that excludes the intensive use of concrete.  

Hi Jeremy,

Roberto has made some great points. I think if it works for you, and your situation, do whichever.  If you choose to go "pure" earth ship, that's great, but don't be afraid of the concrete if it works best for your situation.  No one has all the right answers and to enslave your ideas and dreams through some else's preconception is a mistake.  Concrete worked great for the Romans, and for me personally there are just some things that work better when they are made of concrete.  Footings, posts, erosion control and basically anything you want to stay put for a long time are great uses for concrete, and it holds thermal mass well.  I think it's important to remember to be practical.  If prepping and setting the tires takes X amount of time, and concrete installation equals one quarter of X, I would go concrete because that is time you could be using to create other parts of the earth ship, or whatever you would call it. (and if anyone wishes to admonish me about the evils of concrete, save your breath)

There's no study for longevity in this situation, but my guess is that the concrete will last longer without needing repair as well.
 
I'd equate it to preparing land in a key-line system.  Most people that do it aren't using horses, they're using tractors, because the speed at it which it can be done mitigates the carbon being used to accomplish the task.  Berms and swales can be created and planted quickly and most folks see it as a good trade off.  The carbon they'll sequester in foliage the first year or two will offset the petro that was burned to modify the land. And I agree with this concept: we need to get this planet planted, and quickly, so a little carbon used in the right places can go a long way.

If the end product behaves as you predict and saves you time, money, and carbon foot-print over the long haul, it's probably a sensible move.  Just my thoughts.

Well said, Marcus.

I'd definitely agree that concrete has it's place.  I'll certainly be using some, especially for footings and pilings and such, and also for cordwood and stone structures... and also in final mixes for wall and floor plasters.  It is a wonderful tool, but I tend to try to think of alternatives, and to consider my use of it--- with moderation as the goal.

Use earthship system ideas and Super Adobe (earthbag) for structure.
No Tyres

https://en.wikipedia.org/wiki/Earthbag_construction

No to tires.

Inefficient

First rule/law is conservation of energy.

Tires are toxic. Keep toxic things far away from shelter.

Because he "coined" the name he robbed the concept of its real value so that now, if it is not done with tyres it is not an earthship. I disagree. Massive structures are thermally stable. The more massive, the more stable. Correct design and orientation of the structure are the factors that determine whether it will be comfortably stable, or uncomfortable. I am very close to a good source of gabion fill, so I am contemplating going that route - if I ever get that far. In my book an earthship is an earthship with or without tyres.

When I decided to build my first and last house, I knew I would use alternative building methods. The problem was deciding which alternative to chose. I knew I wanted earth sheltered passive solar, but that still left many options. Choosing to go alternative is easy; finding your way among the myriad methods is not. So, after much study, I chose to use timber frame (post & beam), infill that with cedar stack wall, and slipform stone and concrete foundation walls.
Trying to conserve both money and planetary resources, I cut the timber framing from my property, scrounged cedars where I could, and gathered every stone I could find (and lift) within about five miles of my place.

Slipforming is an old building method where wooden forms are set up wall thickness apart. A flat-faced stone is placed against a form, and concrete is poured in behind the stone, forming a wall with embedded stones facing out. Once the concrete has set up, another layer of forms is placed on top, and the process is repeated.

Now, with two (or more) layers of forms up and concrete set up, you can remove the bottom forms and leapfrog them up the wall, thus greatly conserving form lumber, as you work your way up and along the wall.

Most stones are not very large and heavy. Flat-faced stones do not have to be very thick to cover a fair amount of wall. The heaviest piece of wood in my house is easily heavier than the heaviest stone.

In my search for stone, I found several old home sites where the only evidence of a home having ever been there was a stone chimney or pile of stones. This is a tribute to the enduring quality of stone. It won't rot, burn, or get eaten by insects. After you have it mortared in place, it will remain right there, looking exactly like it does, virtually forever. An added benefit is that externally insulated stone is an excellent heat sink, or thermal mass. It soaks up excess solar heat on cold sunny days, and returns it at night.  Conversely, it keeps indoor temperatures cooler during hot days, acting as a thermal flywheel, evening out temperature fluctuations in either direction. And we get all of these benefits from a free resource!

We mixed our own concrete, which helped to keep costs below the cost of a block wall, not counting labor. I feel I should mention that the stonework is, in the opinion of many, the most attractive walls they have ever seen.  Another benefit is that unlike the typical stick-framed wall, once you pull the forms and mortar, you're done: no sheet rocking, painting, etc. Plus, there's no maintenance ever. Thick stone walls do not transmit sound very well, either, making for a quiet, attractive, evenly heated interior space.  The walls can be insulated on the outside by applying sheet insulation and stucco.
Slipforming is an old method, but it is also still used in modern commercial buildings as well. Basically it means using reusable forms, I built mine all 18" high, and either 4', 6' or 8' long, they were 2x4 frames with plywood or boards on one side.  The frames are drilled on the center of the 2x4 every 2', so they can be bolted together.  The process of using them we called "Space, Lace and Brace".

Space: We started on a poured concrete footer, and placed two 8' forms 12" apart, facing each other, this is for a 12" thick wall. We then took 12" sticks and placed them in a few spots between the two form faces, to keep them 12 " apart.  

Lace: We then wired thru the forms, tightening the wires by twisting nails into the wire, to tension the forms against the sticks.

Brace: Then we braced the forms by temporarily nailing a 2x4 to the top edge of each form and the other end to a stake in the ground to keep the form plumb.

We had collected a large pile of stone, any stone with a flat face on at least one side can be used, I just placed one stone at a time against the inside face of the inner form, and then placed concrete behind them, filling in the concrete with what we called "uglies", or stones without a flat face, to use less concrete. Bolt more forms end to end, and go along the wall, building up to the top of the 18" form. We would do about 30-40' a day, mixing concrete in an old gas mixer. After the bottom layer is set up, bolt another layer of forms above them repeat the process, and then when the second layer is set up, you can remove the bottom layer of forms, and use them for the third and successive layers, "leapfrogging" the forms up and along the walls. This process is described in the Nearing's books, which is where I got the idea from, except we put the stone face on the interior, and insulated the exterior for thermal mass. BTW, excellent concrete can be made with less Portland cement by using crushed limestone base mix, it's what the state uses for the base of roadways. 7 parts base mix to one part Portland.

After the walls were built, I troweled on a thin coat of masonry cement to the exterior, called a parge coat, and then painted on a thinned coating of Portland cement to fill pores in the parge coat. After applying waterproofing, I used construction adhesive to adhere two inches of foam board insulation all around the outside walls before backfilling.


For further reading: Build Your Own Stone House by Karl and Sue Swenke and
Our Home Made of Stone by Helen Nearing.
Stone House: A guide to self building with slipforms by Tom Stanley

Doug

Pictures at-
http://www.builditsolar.com/Projects/SolarHomes/Doug/SlipForm.htm

Firstly:  An earthship makes sense only in a climate that averages close comfortable.  Soil isn't a great insulator, but it has terrific mass to average out the swings.  The proper use of windows can make them good for another 20 degrees C.  It's an awful lot of work.

Secondly:  Cement has huge amounts of embodied energy in it.  In addition the process of making it releases a large amount of CO2 into the air.

So my answer:  Both are poor choices.

Alternatives:

* If you are in a dry climate, look at adobe.  This in essence is an earthship wall without the tires.
* Or use sandbags.  Lot easier to fill than tires
* Make bricks out of rammed earth.  Google CINVA ram.
* COB

In a colder climate:
* Strawbale.
* Leichtlehm  

All of these are much less work than an earthship, and make a better wall.

***

Building your own house is time consuming.  Even the pros get rained on.  Change the sequence:

Instead of Foundation, floor, walls, roof do the roof first.  In effect, build a pole barn.  Build it 4 to 12 feet bigger each way than the house foot print.  Now you have a dry space to work on rainy days, and a shady place to work on sunny days.  A forgotton tool set down doesn't instantly rust.    Later you will finish the overhang space as decks, patios, stone gardens, wood storage, garden tool storage, greenhouse.

Initially build the roof too high.  Use a scissors truss or an A frame truss.  The house underneath has a flat roof.  Later you can fill the space between the flat top of the house and the real roof with a guest room, artists studio or place to hide the teenagers.  Think about this, while you are designing the roof.

Hi Jeremy-

We have been where you are. We explored every possible system, and every variant. Nothing was perfect, and most are either labor or money intensive. Our first building was a tank house for the water flow and equipment of an artesian well. It was a 16' inner diameter scoria bag catenary dome, with 3" of shotcrete inside and out. It has no windows and one door with a small window. The walls are about 18" thick, and it is significantly earth bermed on the back side. With only the additional heat of 4 light bulbs, it has sailed through Colorado winters without freezing. We are very pleased with the performance, but would not want to live in even a complex of them. Too closed in feeling.

We are in the permitting phase of a guest house made from a post and beam system with Hogan brackets. http://www.ezhogan.com/ We chose this system because it allows us to do a lot of the work ourselves, and we are leery of many aspects of someone else building our house. We will wrap the building in Faswall blocks. http://faswall.com This is a high mass ICF system. It costs way more than I wanted to spend, but with the addition of some roxul insulation and lime plaster to the outside, we will have a reasonably well performing building with vapor permeable walls. http://www.roxul.com Not super fantastic like I wanted, but reasonable.

We have limitations. We are around 60 years old, and have been waiting 10 years to find the right piece of land and figure out what we want to build. We live in a high wind and cold winter/hot summer area. Time's awastin'. If we had more time, I would probably lobby for a double wall earthbag system - earthbags ( or poured earth walls or cob) insulated by perlite bags. We talked extensively about modifying the Hogan frame to help hold the bags in place. I think we could have worked it out in a fashion similar to this eco-beam system. http://earthbagbuilding.com/articles/eco-beam.htm

I wish you luck on your project. If you really want to compare the mass benefits of different wall systems, some basic wall weight calculations will be helpful. You are definitely on the right track. Mass with appropriate insulation for your climate is where it's at. Our main house project with be Faswall blocks also, and though I don't like all the concrete it will take, we are building a 500 year house that will house our descendants for several generations if they can get their heads out of their phones long enough to learn how to grow food.

[On the side, your site Doug was one of the first sites I stumbled on when I first started researching slipform stone masonry, and it inspired me a lot early on. So thanks for what you put up on the web. I'm sure it's helped inspire and enlighten many other people!)

An idea.. Just to riff off Doug here, on the ethos of re-use.. using recycled, broken concrete, "Urbanite" was mentioned above by both Roberto and Bryant, who also mentioned slipforming..

Why not essentially use broken chunks of concrete *in* slipforms, instead of stone, or in addition to rocks that you find on site in excavating. Since your walls are going to be structural, load bearing, and concrete has thermal mass, you could get away with making very thick walls this way, like 2' thick or more, and by using the broken chunks in the middle, not just as facing, but in the middle of the poured concrete core, you could probably save money on concrete, reduce the environmental impact, and effectively reuse broken concrete that would have gone to waste..

In researching slipform masonry over the last several months I've found that the basic idea of building by forming walls in wooden forms/shutters, in lifts of 1' or 2' at a time, essentially embedding large chunks of aggregate in thick mortar beds is really, really, old. There are cobblestone/flint masonry cathedrals in Britain that are 1000 years old built just like this.

If you can find someone looking to get rid of some heavy broken concrete fill then you could possibly get a good deal of building material for free. The wall is essentially rubble embedded in thick mortar, and doing it this way could lessen the amount of concrete that you use, thus lessening the ecological impact.

Doug Kalmer wrote:
...Slipforming is an old building method where wooden forms are set up wall thickness apart. A flat-faced stone is placed against a form, and concrete is poured in behind the stone, forming a wall with embedded stones facing out. Once the concrete has set up, another layer of forms is placed on top, and the process is repeated.

Now, with two (or more) layers of forms up and concrete set up, you can remove the bottom forms and leapfrog them up the wall, thus greatly conserving form lumber, as you work your way up and along the wall.

Most stones are not very large and heavy. Flat-faced stones do not have to be very thick to cover a fair amount of wall. The heaviest piece of wood in my house is easily heavier than the heaviest stone.

Again, just adding to what Doug posted, just to show how old this technique is see this link on "building gravel wall houses" (from an old 1865 issue of The American Agriculturist )

https://books.google.com/books?id=aKlAAQAAMAAJ&pg=PA175&lpg=PA175&dq=%22gravel+wall%22+%22curbing+boards%22&source=bl&ots=TWNFLM_PzH&sig=_8XDfsE0Oskaj5t0o_aoK6s_THg&hl=en&sa=X&ved=0ahUKEwioponk2pbWAhVB4iYKHWs7DPUQ6AEIKDAA#v=onepage&q=%22gravel%20wall%22%20%22curbing%20boards%22&f=false

Lots of options, all carry degrees of embedded energy but there are ways that we can intelligently take routes maybe that mitigate some problems..

Modern concrete based on portland cement does have a lot of embodied energy, this is true, and other ecological impacts. But it also can make very long lasting buildings if done some ways. If done other ways it falls apart after a generation.

Someone gave me advice in a similar thread about using Natural Hydraulic Lime instead of cement. But unfortunately American Type S building lime isn't hydraulic and very suitable for building, because it's cooked far too hot and thus isn't reactive. It makes extremely weak mortar.

Natural Hydraulic Lime isn't produced in the USA, and what's here is imported from Europe. (There was a USA based company Virginia Lime but they seem to have gone out of business...)

Also non-hydraulic but reactive lime suitable for mortars are produced by a small handful of manufacturers and are expensive. Some traditional stone masons have gotten around this by gauging their lime mortar with a tiny but of portland cement.

However a pumice supplier, Hess Pumice, now makes an artificial hydraulic lime mainly for interior plastering. Its properties are similar to European NHL. Though its marketed for internal plastering it is also suitable for mortars. It can be mixed strong enough for a mortar that's as strong as, or stronger than, many historical lime based stone mortars.

http://limestrongfinish.com/roman-cement.html

The same company has a range of pumice conventional concrete additive products that can replace some Portland cement by volume. Which makes conventional concrete stronger, but with a better ecological impact because a portion of the cement is actually substitute with a product that not only has less embodied energy but as a Pozzolana actually makes the resulting concrete stronger, so it decays slower due to freeze/thaw cycles, which means your building can be reused after you are no longer here. A building that can be reused for generations with minimal repairs has less of an ecological impact than one which is no longer useful after 30 or 40 years, or less..

So basically, why not slipform with both rocks and broken concrete chunks, but using a mortar/concrete bedding based on a mix using a hydraulic lime product like Limestrong? I got pricing from a distributor for a project I'm starting, and their pricing was way less than imported Natural Hydraulic Lime.

Or slipform with conventional concrete that is gauged with a natural pumice pozzolana, not just as an additive, but as a partial replacement for a portion of the portland cement in your concrete mix.

Or for more strength using the lime mortar as the base of your concrete but gauging the it with a portion of portland cement.

Again, there are 1000 year old cathedrals built in a slipform like manner, much less than pre-civil war 'gravel houses' (the 19th century concrete was lime mortar+gravel based) using weaker lime based mortar that are still around.

The biggest problem is curing time, it takes far longer for lime concrete to cure than for modern portland cement based concrete. Historically lime mortar and concrete can be made to initially set faster by gauging with cements (either natural cements or portland cement)

Now how much of this will fly with your local building codes is an unknown.. but there are options at least.

Hi, Jeremy. My name's Michael. I am a chef engaged in restorative agriculture in South Texas.

It's actually quite remarkable: people you meet in a place like this are all here because they want to do good. That's quite unusual, and deserves special respect.

But the impetus to do good comes from our deepest, most central wiring--so what we feel is good, we feel it to within an inch of our lives.  Our opinions ARE us: closer to us than flesh can be.

(I guess it might go without saying, but) there is a great tendency to divide the world into right and wrong, black and white, good and bad. We are all trying to walk a straight line, and we need the feeling of an up and a down to be able to navigate through the morass.

It is precisely BECAUSE we want to do good that we are offended by that which falls outside those parameters that we agree with and can make sense of. (So when people are critical, don't fault them: in all of history, no one who didn't care ever complained.)

When I shop in the farmers market, there are farmers who grow conventional produce, others who produce organic, and still other who work on a biodynamic / permaculture model that hasn't got all the kinks worked out yet.

It would be easy to damn everyone but the permaculture farmer, and let the other competitors shrivel up and blow away. That would be the idealist thing to do. But even though I side with the permaculture farmer, I don't do this. Here is why.

Local agriculture--performed by small groups of imperfect people--is up against the biggest lion this world has ever known. Choke them, and (the effectiveness of boycotts cannot be denied) they will easily fold. If I allow to die those small farmers whose practices I don't agree with, my constituency, who face the lion, grows still smaller. The triumph of the lion becomes more likely.

All those small operations are struggling to stay alive and relevant. Including...notably...me.  I will make an effort to support all of them, and (after paying forward the money) try to influence them by the position of what I PROVIDE, not what I DENY.

So back to your house of concrete. Let's say you do this practical thing, and it gives you the strength you describe. What will you do the next day?

OK, I have to ask, what are CMU's?

Bryant RedHawk wrote:I believe that if you start replacing the thick tires (soil thickness not the tire thickness) then you are moving away from earthship design as I understand it.
As far as the reduction of issues, yes it would work better but it is not serving the function of re-purposing that the earthship was designed to do.
As far as the thermal mass, it would be able to have more thermal energy stored, thicker is better, black it the right color for thermal mass storage.

My understanding of the RMH is that the heat comes through the exaust pipe (flue) so I don't think you could run one RMH to heat an entire floor area, perhaps two to three would be needed.

Redhawk

Personally, I would use stone masonry and maybe other resources that are natural. While it might not be a "Michael Reynold's" earthship. I'm not Michael Reynolds. I may adapt the design or concept for use of earth, gravel, dirt, and stone masonry where possible. Partly due to my locality, the prevalence of basalt that can either be quarried or otherwise sourced locally. It gives the load capacity. In cases, I may use gabions. I commend those to recycle which is fine. As a building designer, I make the determination for the given project. While it might not be purist approach from the Michael Reynolds sense of purist, I may still use the term "Earthship" with some degree of deviation from the purist sense but within limits of natural and sustainable low carbon footprint ethos.

While tires maybe fine, there can be real world apprehension for using tires in some places where I can use stone masonry (not masonary) or reinforced stone masonry from a structural design and aesthetic perspective. If you have a hillside site location, you have to plan for retaining wall capacity.

One guiding principle is the use of earth-based materials that are natural or near natural state and requires little to no carbon footprint. Concrete, albeit is earth based, is made through a process with high carbon footprint. Masonry from stone can be dry stacked, if done well, can be pinned/reinforced, as well as well as survive seismic events. Look to our Inca friends. The hardest part is the labor involved but it was done without the modern factory process or use of kilns or other processes that contributes to carbon emission into the atmosphere.

John C Daley wrote:OK, I have to ask, what are CMU's?

Concrete masonry units.

Straw bales!  I love that our walls were sourced from right down the road, came "pre-compacted", and were able to stack to make 16 feet of ceiling height.

I think we paid less than $1500 (12 years ago) for all the bales which built all the exterior walls in our 1200 SF house.  

The R value is great and the house breathes fresh air + we know there is nothing toxic used.

Marcus Billings wrote:Roberto has made some great points. I think if it works for you, and your situation, do whichever.  If you choose to go "pure" earth ship, that's great, but don't be afraid of the concrete if it works best for your situation.  No one has all the right answers and to enslave your ideas and dreams through some else's preconception is a mistake.  Concrete worked great for the Romans, and for me personally there are just some things that work better when they are made of concrete.  Footings, posts, erosion control and basically anything you want to stay put for a long time are great uses for concrete, and it holds thermal mass well.  I think it's important to remember to be practical.  If prepping and setting the tires takes X amount of time, and concrete installation equals one quarter of X, I would go concrete because that is time you could be using to create other parts of the earth ship, or whatever you would call it. (and if anyone wishes to admonish me about the evils of concrete, save your breath)

There's no study for longevity in this situation, but my guess is that the concrete will last longer without needing repair as well.
 
I'd equate it to preparing land in a key-line system.  Most people that do it aren't using horses, they're using tractors, because the speed at it which it can be done mitigates the carbon being used to accomplish the task.  Berms and swales can be created and planted quickly and most folks see it as a good trade off.  The carbon they'll sequester in foliage the first year or two will offset the petro that was burned to modify the land. And I agree with this concept: we need to get this planet planted, and quickly, so a little carbon used in the right places can go a long way.

If the end product behaves as you predict and saves you time, money, and carbon foot-print over the long haul, it's probably a sensible move.  Just my thoughts.

Hear hear!  I wholeheartedly agree that one must always consider the big picture and evaluate a situation holistically in order to make the best decisions, rather than embracing slavish devotion to a simplistic rules-based paradigm.  Yes, concrete has very high embodied energy and carbon footprints.  It also has many attributes, including durability, versatility, quick and easy application, relatively low monetary cost, high resistance to water, high resistance to erosion, total resistance to biological decomposition, high thermal mass... and I could probably go on.  Thus, it should be used judiciously in those situations where its attributes are most desirable.

Simply repeating the mantra "Concrete not green; concrete bad!" is no way to make smart design choices.

Having said all that, I probably wouldn't choose to build an Earthship-type structure using concrete-filled MCUs or a traditional poured concrete wall.  I suspect doing so would prove effective, but it wouldn't be my first choice.  People above have suggested plastering over earthbag walls or over stone-filled gabions, both of which strike me as more suitable choices.  These would produce walls that are functionally identical - or at least very similar - to the traditional tire walls: you'd retain the same aesthetics, the same ideals of using natural earthen materials, and the same result of a highly massive, waterproof, non-biodegradable wall against which to set your earth berms.

Yes, technically your walls would include small amounts of either nylon fabric or steel wire, which are virgin materials, as opposed to the re-used discard tires.  But let's be real: you are talking about less than 1% of the wall's mass, whereas 99% is either earth or stone.

I have never worked with stone gabions before.  But I have been involved in an earthbag build, and while laborious I believe this to be a much easier technique to undertake compared to a tire wall.  I have also, in fact, visited a completed Earthship-like dwelling - it was not precisely an Earthship, but close enough that I will use the term - made with earthbag walls.  The owners/builders were quite happy with their construction experience and with their finished structure.

I am also intrigued with the detailed description above - thanks, Doug! - of the stone-faced slipform concrete wall.  A very appealing result, if you click his link to look at his pictures of the finished wall.  And if you read through his entire description, there are a good number of steps you can take in the process to reduce the volume of concrete, and of Portland cement in particular, used to make your wall.  I'm still not sure if this would be my first choice for building an Earthship.  But if I were dedicated to building one with concrete walls, that is definitely the process I would follow.

Lynne Cim wrote:Straw bales!  I love that our walls were sourced from right down the road, came "pre-compacted", and were able to stack to make 16 feet of ceiling height.

I think we paid less than $1500 (12 years ago) for all the bales which built all the exterior walls in our 1200 SF house.  

The R value is great and the house breathes fresh air + we know there is nothing toxic used.

I have also built a straw bale home, and while it is a good technique, I must propose that straw bales are an extremely bad choice for substituting the earth-filled tires of a traditional Earthship.  If that is indeed what is being suggested here.  If not, then Lynne's post really should be moved to a different topic.

You would never want to set an earth berm against a bale wall.  The potentials for moisture intrusion and decay are too great.  Moisture intrusion could mean both liquid water from the earth berm side, and even water vapor from the interior air side, unless your building had copious ventilation.  A bale wall is intended to "breath" on both sides - and for the record, this means to regulate water vapor content; plastered bale walls actually form a total air barrier, and don't in any way actually breath fresh air into your house.  I realize that Earthships are usually built in the desert, but even there I wouldn't trust a bale wall in an "underground" or "earth-integrated" application like this.

Also, you wouldn't desire a highly insulated wall inside your Earthship.  The idea, as I understand it, is to instead have a mass-heavy wall that ties thermally into the mass of the surrounding berms on the North, East, and West sides of the structure.  Thus, your inside living space benefits from the huge thermal inertia of all that combined mass, wall and berm together.  Insulating yourself from it would be counterproductive.  Earthships are, at the simplest conceptual level, radical examples of passive-solar architecture.  The core tenet of passive solar architecture is to connect your living space to a large thermal mass and, if anything, insulate on the outside; not to insulate your living space from the mass.

Now, the idea of a straw bale wall on the South-facing wall of an Earthship - the one wall of the building that faces the outside air, as opposed to being buried behind an earth berm - has some potential.  However, these South-facing walls in a classic Earthship are largely glass.  The lower portion, which could effectively be made of bales, constitutes a small part of the total wall.  For this reason, I'm not sure if I would go to the trouble of organizing a bale raising for what is basically one stem wall out of the entire building.  Plus, many Earthships have a large raised garden bed, perhaps even with a large integrated pond, built into the inside of that lower portion of South-facing wall, typically running the length of the entire wall.  Putting a bale wall behind this would be, at best, probably redundant; at worst, potentially problematic due to the threat of moisture intrusion, as discussed above.

I realize this thread is super old and I found it researching building materials. Just wanted to add (if it hasn’t already been said here) that cement is also full of toxic and corrosive chemicals. Earth bag or straw bale houses are way more natural, easy to build and would be much less expensive than a cement house. And depending where you’re building, they are much less prone to damage from earthquakes.