FAQ - Earthship Eco Homes

Frequently Asked Questions

What is an Earthship?

Earthships are self sufficient buildings with no power, water or sewage bills, made with lots of recycled materials and with minimal need for heating and cooling.
Earthships are:

highly energy efficient - a few solar panels and batteries are all thats's needed to power an Earthship
highly water efficient - rainwater tanks, filters and a pump supplies all your water needs.
able to grow food year round in an indoor garden irrigated with greywater from the shower, hand basin, washing machine.
built with easy to learn eco construction materials and techniques, so you can DIY with your friends and family.

To learn more about the origins of Earthships in the USA go to the official Earthship Biotecture website. Earthships were invented by American architect Michael Reynolds decades ago (in the 1970s) and there are thousands of them around the world, especially in North America. In Taos, New Mexico, USA there is an Earthship community called The Greater World with over 100 people living totally off the grid.

Sunroom at Earthship Ironbank, South Australia, greywater garden with banana palms on north side of building

what are the benefits of earthships?

There are many benefits to Earthships:

be free from the power, water and sewage “grids” which are causing environmental impacts that the Earth can’t sustain.
be in control of where your power and water comes from and where your sewage goes.
save money on utility bills and support the renewable energy industry.
minimise the use of “virgin” materials that are ripped from the ground and the forests .
upcycle waste tyres - 55 million of them per year in Australia.
have a hand in the construction of your own home and build it with your friends and family.
grow your own organic, zero-food-mile food in your Earthship, year round.
recycle wastewater - grow food and other plants with your greywater and blackwater.
be more independent and less reliant on the grid.
naturally comfortable, stable temperature year round.
highly resilient to natural disasters such as bushfires, storms and floods.

How do I get an Earthship?

It is unlikely you will find one for sale... so you will need to build one.
You need money, land, permission and a builder.

Money: if you need to borrow money from a bank you will need to hire a licensed builder and sign a contract with them. Otherwise, if you have enough funds you can become an owner builder and save money. You will still need a qualified builder or surveyor to supervise the construction process but you don't need to sign a contract with them.
Land: there is some criteria described below regarding suitable land. A site without power, water and sewage will be cheaper and is ideal for an Earthship.
Approval: you need plans and reports that have all the relevant info required by Council/Shire.
Builder: you will need a builder who is willing to try something new. If you are self-funding your project, without a loan from a bank, you can be an owner-builder, but you will still need someone licensed to supervise the construction of your Earthship home.

Money

How much do earthships cost to build?

They cost approximately 5-10% more than a home of the equivalent size and quality. This is because Earthships have solar panels, batteries, rainwater tanks, and other off-grid systems which, of course, adds costs. Over time, these initial costs are "paid back" as you have no utilities bills. It is like you have prepaid your utility bills at a known, competitive rate.

A useful rule of thumb is about $3500 per square metre of "gross floor area" (this is the "footprint" of the house - you can think of it as the size of the floor slab). If you are a very energetic and resourceful owner builder you might achieve $2000/m2. If you want a more complex design with lots of "bells and whistles" then the price might go up to $4500 per square metre. Hence a two bedroom home with a footprint of 150m2 will cost $525K. Maybe you could do it for $300K as an owner builder.

To really know the costs you need to hire a Quantity Surveyor to study the plans in detail and make a highly accurate cost estimate. Otherwise work on $3500 per square metre as a rough average, realistic cost. See the "residential" section of this website for typical construction costs in Australia: www.bmtqs.com.au/construction-cost-table 4br Full brick home, level block, single level, unique design is a good example comparable to Earthship. Here is some research including infographics of housing costs in Australia. It is interesting to note that the costs change in different States.

how can i reduce the construction cost?

Build Small
If you have a limited budget, the best way to save money is to make your home small and efficient... you can always make it bigger later, if you really need to; Earthships can be designed to be easily extendable. Although the construction cost of an Earthship may be similar or slightly more than a similar size home, the ongoing running costs will be much less.
Check out the tiny-ship "EarthBnB" - click here.

Buy Ideal Land
Buy land that is ideal for an Earthship. If you have a block of land that slopes in an undesirable direction you may need to do a lot of earthworks which increases the cost.

Minimise Off-Grid System Size
The size of your off-grid systems is also a factor: the more you "size up" your systems (more solar panels, more batteries, more rainwater tanks) the more expensive it becomes. Thankfully the Earthship is inherently very energy and water efficient so your systems can be relatively small.

Run Workshops & Products
Earthships are labour intensive to build, so to reduce labour costs and to create a fun and educational experience, it is possible to run a workshop. Students or volunteers are generally willing to pay a fee for the experience of helping you build your Earthship because they are learning useful skills and meeting like minded people. It helps if you make it fun, educational and provide healthy food and a good camp site with showers and toilets. You will need to hire some experienced Earthship builders and workshop coordinators to ensure that the students/volunteers do good work, learn, and have a good time. In return you get a lot of free labour and an enjoyable experience. You will also need to hire caterers if you can't do the catering yourself. Can you find someone upgrading their renewable energy system?

Salvage Materials
Buying second hand materials can reduce costs, although it is not without difficulties. You need a safe place to store the materials and you may also need to repair or restore the materials. Furthermore they need to be "designed in" to your home so you need to let your designer know what you have, or can get, and this can then be worked into the design. For example, you have some old jarrah floorboards in the shed. After a discussion with your designer it is agreed that these would make for good eave lining materials in the carport and the ceiling in the bedrooms... but you don't have enough for the other rooms. Will you try to find more, or use a different ceiling material in other parts of the house? Maybe you can pick up some second hand solar panels and batteries, knowing that their life span is going to be shorter and they may not be as reliable.

EarthBnB tiny-ship

how much do plans cost?

The cost of "architectural plans" (this is what Earthship Eco Homes provides) will vary according to the size and complexity of the Earthship.

For an existing design that does not require much alteration to suit you and your site the cost will be approximately $15K.

For a new custom design tailored to your site and specific requirements the cost will be approximately $25-$35K depending on size and complexity.

Other Design/Engineering/Approval Fees
In addition to the cost for the architectural plans, there are other fees amounting to approximately $5,600 to $8,000

Approval Fees (council)... $500+
Bushfire Attack Level (BAL) assessment... $400
Soil Bore Logs... $500 - essential for structural engineering and wastewater system design
Surveyor $1200 - to map your site boundaries and topography (create contour map)
Structural Engineering... $3000 - $5000
Wastewater Engineering... $950 - $1500
Energy Assessment... $400 - $600

Prices are approximate and dependent on your site and design

How do I finance an Earthship?

The same way you finance any new home.
If you need to borrow money from a bank you will need to sign a contract with a licensed builder to build your Earthship because most banks won’t loan money to an owner-builder.
If you have the money and do not need a bank loan, you can be an owner-builder.

Can Earthships be insured?

Yes. Earthship Ironbank is. The insurance company will probably list your wall construction as "other" as they will not have the correct category for "tyre walls" on their system. The important thing to the insurance company is that the building complies with all the relevant Codes and Standards.

What are the running costs of an Earthship?

Very little. This is one of the great advantages of Earthships. If you are fully off-grid with power, water and sewage treatment you don’t have utility bills to pay anymore! But you will need to spend approx $100-$200 per year on water filters, have a savings plan for new batteries every 10 or more years (e.g. $500 per year) and eventually you will need new solar panels and water tanks. You should try to save about $1000 a year to cover all these eventual expenses. It's a lot less than paying for energy and water from the grid!

How much money will I save?

Have a look at your utilities bills.
The average Australian electricity bill is about $1200 - $1500 per year.
The average Australian water bill is about $900 per year.
The average Australian gas bill is about $900 per year.
In total, roughly $3000 per year, on average.

Assume you live in your house for 30 years.

The cost to run the house for 30 years is $90,000.
Over the coming decades the cost of electricity, water and gas is likely to rise.
So the cost might be closer to $100,000.

The cost of the off-grid systems for an Earthship are typically:

Renewable Energy System (solar panels, batteries, inverter etc) $30,000 - $40,000
Water tanks, filters, pumps $10,000
Wastewater system $15,000 - $20,000
Total of $55,000 - $70,000

Average Minimum Saving = $100,000 minus $70,000 divided by 30 years = $1,000 per year.
Average Maximum Saving = $100,000 minus $55,000 divided by 30 years = $1,500 per year.

In summary, by living off-grid you save money and you are not exposed to price rises. Also (and more importantly?) you are reducing your carbon footprint and helping the environment. This is because the grid causes a lot of pollution whereas off-grid system components are comparatively "green"... they still have environmental impacts but they are far less than the grid.

Earthships make it easy to go off-grid because they are inherently energy and water efficient due to their design features, and hence all the off-grid system as scaled-down and therefore cheaper that what you would expect to need on a conventional home that is off-grid.

Off-grid is green and saves $$$

Land

what type of land is suitable?

Checklist for ideal site:

size/area is large enough - refer to floor plan of your Earthship - typically Earthships are quite long in the east/west axis so a "wide" block of land will be needed.
solar access - good orientation (facing north) and shadowing (no trees from NE to NW)
views to the north
ideally trees (bushfire hazard) would be to the south east and west at least 30m away
slope direction suitable (flat sites are ok, north facing slope are best, south facing slopes are worst)
soil type: not highly reactive clay
watercourses not too close; room for land application area (wastewater irrigation area)
look for an "off grid" site if you are trying to save money - sites with power, water and sewer generally cost more
look for a steep north facing site if you are trying to save money as steep sites can be difficult to develop and are therefore cheaper. Due to the Earthship's integral retaining wall, steep north facing sites are suitable for Earthships.
check with your designer before buying your land!

How much land do I need? what size?

Earthships are long and skinny to ensure good natural lighting, passive solar heating and ventilation. So, for a typical 3 bedroom Earthship a minimum block size would be approximately 45m in the east west direction and 20m in the north south direction for the building alone. For a small 1 bedroom Earthship 20m east/west by 15m north/south may be possible.

You also need space for a garden, and perhaps a garage, carport, and the wastewater irrigation area which could be 200-400m2.

how much space with be needed for the wastewater system?

If you are NOT connecting to a municipal sewage system you may need 200-400m2. This is known as the "land application area" (that’s a technical term meaning your leach field, where the wastewater can safely soak into the earth) and it will probably need to be 50m from existing dams, bores, creeks, rivers, and other water sources to satisfy local environmental protection requirements. This is where the wastewater engineer gets involved. They will take soil samples from your site as a first step to understanding how to deal with the wastewater.

what soil type is best?

A bit of clay in your soil is a good thing for making earth renders. Sandy soil is fine. Highly reactive clay soil might mean more expensive engineering measures such as heavy duty concrete footings. You can do some quick tests to determine clay content to establish if you can make earth renders, but determining the exact soil type (which is important info needed for structural engineering) is best left to an expert. You will need some "soil bore logs" (at least three) where you intend to build your Earthship for structural engineering purposes and you will need another soil bore log where you intend to locate your land application area (wastewater soakage area).

One of the advantages of tyre walls is practically any type of soil will be suitable for putting inside the tyres, whereas techniques such as rammed earth required very specific soil, aggregate and binder (cement) mixes.

what is the best direction to face the earthship?

SUN "SOLAR ACCESS"
Also keep in mind that you want a nice sunny spot throughout the whole day with very little shading from trees, houses, mountains etc. You need to face your Earthship roughly north (or south if you are in the northern hemisphere) - approximately 20 degrees either side of north is ok: it is not always possible to face due north and it really doesn't matter if you are facing slightly to the east or west. Face east = extra morning sun. Facing west = extra afternoon sun. Due north is best.

what is the best slope direction?

A gentle slope that faces north is ideal because it helps with solar access and reduces earthworks. It also helps with moving wastewater - with gravity, rather than a pump.

Steep, north facing slopes can be ok due to the Earthship's design which includes a retaining wall that can be "cut into" the side of the hill/slope.

Steep slopes in other directions can be problematic requiring more retaining walls and earthworks (expensive!).

Flat sites are fine for Earthships; many of the Earthships in America are on flat sites.

how can i deal with bushfire prone land?

As Earthships are inherently bushfire resistant, they are ideal for bushfire prone areas, but it is still helpful if large trees are far away or to the south, east and west of the building. The "Bushfire Attack Level" (BAL) will need to be determined if it has not already (ask Council). Once the BAL has been determined, distances from trees to the Earthship will be dictated.
Click here to see the bushfire resistant "Fireship".

can i build on a small block in the suburbs?

Here are two great examples of suburban Earthship homes by Earthship Eco Homes. Earthship Goolwa and Earthship Narara.

In the suburbs a genuine “Earthship” may be impossible if the size and orientation of the block of land is unsuitable. If the size and orientation is ok, that is, you can can face the Earthship roughly north, the next hurdle would be compliance with the Council’s planning rules in terms of what the building looks like - it needs to harmonise with the street scape. Talk to the Planning Officer in your council/shire about the planning rules and what the building needs to look like - or hire Earthship Eco Homes to do this. Ideally the glazed northern side of the Earthship needs to face the street; facing the earth berm to the street may be considered "ugly" and not be allowed.

As mentioned previously, land without power, water and sewage connections is ideal for an Earthship and is likely to cost less than a block of land that already has all these connections to the grid. Beware of the grid! On that note, you may like to check your options for connecting to the internet and the mobile phone network.

how much rainfall do i need?

RAINFALL
It's a good idea to check the rainfall and then think about how climate change may effect future rainfall. In Taos, New Mexico, the home of Earthships, they have only about 250mm of rainfall per year. If the rain doesn't fall at the right time they can run low on water an need to call in a truck for a refill. To solve this problem you can add more rainwater tanks but only if your roof is large enough to catch the rain - add a shed/garage for more roof collection area.

First you have to catch it, then you have to store it... then you must use it wisely!

Council Approval

Is it possible to get approval to build an Earthship in my council zone?

Yes, it is possible. Many people IMAGINE that they can’t get approval and so they never even try!

Earthship Ironbank, was the first Earthship to gain council approval in Australia. Subsequently other "Earthship" and "Earthship Inspired" projects have also been given approval in Kinglake VIC, Marulan NSW, Brooks Bay TAS, Jurien Bay WA, Narara NSW, East Augusta WA, Inman Valley SA, and Goolwa SA.

Because Australia has a National Construction Code it means that the Earthship construction methods are applicable right across Australia.

The only major issue with Earthship Ironbank was with the indoor greywater system (greywater garden), however there are legitimate ways to enable you to reuse/recycle your greywater productively. And... in SA this system is now approved!

How do I get approval for an Earthship?

Just follow the standard procedure...

Step 1 Planning Approval (also known as Planning Consent)
First you need to get Planning Approval from your council/shire - this relates to the size, shape, colour of your home, distances from your home to your boundaries, overlooking neighbours, shading neighbours, and the function of the building (note: it does NOT relate to structural design and structural materials).
Basically you need a site plan, floor plan and elevations - this is included in all Earthship Eco Homes plan sets.
In some states/territories you may be able to use a Town Planner instead of Council for getting Planning Approval.

Step 2 Building Approval (also known as Building Rules Consent)
Second you need Building Approval and you get this from council/shire or from a private certifier/surveyor*. This relates to compliance with the National Construction Code (NCC) and Australia Standards.
You will need the services of a structural engineer, a wastewater engineer, energy assessor, building designer/architect/draughtsperson and finally a private certifier/surveyor*.

The structural engineer’s job is to demonstrate that the design won’t fall down in an earthquake or blow away in a storm.
The wastewater engineer’s job is to demonstrate that the wastewater system won’t pollute the ground water or nearby creek.
The energy assessor’s job is demonstrate that the design is energy efficient and meets the minimum requirements of the NCC.
The architect/building designer’s job is to provide detailed plans that demonstrate compliance with the NCC and Australian Standards e.g. in terms of termite protection, bushfire protection, ventilation, natural lighting, thermal performance etc.

The private certifier/surveyor* assesses all of the information provided by the professionals listed above and may request changes as required by law (National Construction Code, local council/shire, Australian Standards). Any necessary changes are implemented and a final set of documentation is stamped by the private certifier/surveyor* who issues "Building Approval" for your project.

The Building Approval documentation is then submitted to Council/Shire to apply for Development Approval. When you have Planning Approval and Building Approval you have satisfied all the requirements and Development Approval will be issued by Council/Shire. Generally Council/Shire will "rubber stamp" (approve without hesitation) the documentation and issue Development Approval without any further discussion/deliberation etc. This is because all your ducks are in a row; all the liability for each part of the project have been "owned" by the various professionals, the private certifier/surveyor* ultimately signing-off that everything is above board and compliant with all the relevant codes and standards.

Note that the terms "Planning Approval", "Building Approval" and "Development Approval" change in the various, States, Councils, Shires but essentially this staged approval system is the same throughout Australia.

* use a private certifier/surveyor for Building Approval rather than Council because, in general, private certifiers are more willing and able to conduct the research required to assess the rather unusual Earthship design and construction methods for compliance with the National Construction Code and other relevant Australian Standards. They are also much quicker than Council typically only taking a couple of weeks; councils can take months. Costs are similar.

Why should I bother with approval?

It is wise to get approval if you want to insure or sell your Earthship. Imagine making an insurance claim only to be told your insurance policy is not valid because your home is "illegal".
If you get approval you can be more confident that it won’t blow away or fall down and kill someone.... and if something does go horribly wrong you are not to blame.
If (when?) you get caught without approval you have to pay fines and then they (council) will make you get retrospective approval, or demand that you demolish the house! So you might as well get approval.

Is it possible for an Earthship to pass the minimum energy efficiency requirements?

Yes it is possible... you need to have a knowledgeable energy assessor who understands the nuances of the energy assessment rules known as the Nationwide House Energy Rating Scheme (NatHERS). Unfortunately Earthships are unfairly disadvantaged because the software used to do the NatHERS energy assessments is not designed to deal with tyre walls, greenhouses, earthtubes (cooling tubes), and earth berms. Furthermore the greenhouse, which is not intended as an air-conditioned living space, may have to be counted as a space that is heated and cooled. However, with a knowledgeable, experienced, energy assessor and private certifier you can meet the minimum energy requirements. In reality you can rest assured that your Earthship will be very energy efficient, exceeding the PREDICTION made by the FLAWED SOFTWARE.

How much does approval cost?

When you add up the costs of the all the design and engineering professionals and the cost of the approval process itself, depending on the size of your Earthship, it will be in the range of $8,000 to $26,000. See How Much Do Plans Cost above for a breakdown of the costs.
It's a lot of money but it it means the building is legal, insurable, sellable, and structurally sound.

Builders & Building Process

where is a good place to find a builder?

Earthships are only 10% different (the tyre walls) and 90% the same as other homes.
If you decide on a Rammed Earthship then you are now looking for a rammed earth home builder.
So just about any builder has the capacity to build an Earthship (they just don't know it!)
At the moment there are very few Earthship builders in Australia.
The plans from Earthship Eco Homes explain how to make a tyre wall and the other Earthship innovations (such as the wastewater plumbing) so this enables any builder/plumber to successfully complete this type of building.
Try talking to builders who do non-conventional methods such as strawbale, hempcrete, superadobe, mudbrick, rammed earth etc as they may be more likely to want to try something new.

do i need a builder?

As mentioned in the Money section, a licensed builder is essential if you need a bank loan to fund the house construction. Banks will not give you the money - only the builder.
Even if you have the money (no bank loan needed) you need someone qualified to supervise you, as an owner-builder, to verify that your Earthship has been built correctly, to code. A licensed builder, site supervisor, or building surveyor may be able to fulfil this role depending on the state/territory you are in.

How long does it take to build an Earthship?

The time taken is determined mainly by you and your builder depending on how much time, energy and money can you throw at the project. With many volunteers helping to build the tyre wall it can be done in two weeks, then the roof, floors and windows may take another four to eight weeks depending on the size of the Earthship.

How do I build an Earthship?

1. Use a licensed builder who is willing to try something new. Earthship Eco Homes can support your builder one on one to read the plans and understand any unusual construction details, e.g. tyre walls and bottle walls. With the exception of the tyre and bottle walls the construction techniques are conventional and will be familiar to your builder. I recommend Enduro Builders who are the builders of Earthship East Augusta. Also see Where is a Good Place to Find a Builder above.
2. Owner Building is another option (if you don't need a bank loan). Usually all it takes is a short course (or simply some fees) to become an owner-builder. It is up to you how hands-on you want to be: you can do lots of building yourself or you can contract out the jobs you are not confident with and, of course, there are some things that MUST be done by professionals e.g. plumbing and electrical. Part of the beauty of the Earthship is the simplicity of the construction methods: tyre pounding, bottle and can walls, rendering. Attending a workshop is another option for learning the Earthship construction methods which by their nature are easy to learn (Earthships were designed to be easy to build).
3. Run your own "workshop" - invite friends, family and everyone(!) to come help build your ship - that's how Earthship Ironbank was built! Earthship Eco Homes runs workshops, so please check the workshops webpage.
Earthship networks such as Earthship Australia and various social media groups can help attract people to your project. Earthship projects can be wonderful ways to meet like-minded people and learn new skills that may inspire and empower others to go forth and build sustainable homes, for themselves and helping others!

Tyres & Tyre Walls

Where do I get tyres from?

Your Local Tyre Store
You can generally get tyres for free from your local tyre retailer. They are usually very happy to give them away because otherwise they have to pay to get rid of them. It helps if you explain that you are “building retaining walls” and also you should mention you have council approval, especially if they seem reluctant to give you tyres. This usually satisfies them that you are not going to dump them in the environment. The EPA holds them accountable so sometimes they are quite suspicious of people who ask for old tyres.

Getting "paid" to take tyres
You may even be able to negotiate a fee for taking the tyres off their hands! $2 per tyre would not be unreasonable; however, you may have to get special permission from the EPA for the privelige of "disposing" of waste tyres in a council approved project. Some Earthship builders in Australia have been able to negotiate credit for tyres taken which they can use for new tyres... that's right you could get a whole new set of tyres for your car for free if you build an Earthship.

Recycling Facility
Another great place to get tyres is from your city’s tyre recycling facility. They are also usually happy for you to help them “recycle” the mountains of tyres they are dealing with especially when you tell them you have a council approved Earthship. 55 million waste tyres per year in Australia... enough to build about 55 thousand Earthships!

Rural Properties
Beware of tyres that have been used as tree guards or on farms for various purposes such as silage production. If they have been in the sun for many many years they might be a bit "rotten" i.e. crumbly and not as strong as they should be. They might be ok but you should check them carefully before agreeing to a delivery.

How many tyres will I need?

It depends on the design and tyre sizes but for a 3 bedroom Earthship you will need roughly 800-1000 tyres.

What is the best size tyre for building Earthships?

You can use most tyre sizes for cars and four wheel drives. Large tread width tyres go on the bottom of the wall with smaller tread widths to the top. Each course should be of the same or similar tread width (first size identification number on the tyre). Earthship Ironbank was built predominantly with 205/65/R15 tyres because this is a common tyre size in this part of the world. But we used many other sizes too. You don’t need to be too fussy. Just about any car tyre will work.

Do tyre walls off-gas?

No, not as far as anyone can tell. When you visit an Earthship you can NOT smell tyres. Tyres tend to be very smelly (off-gassing) in the tyre showroom, but after they have been out in the weather, on your car for a while, they don’t smell anymore. Furthermore, in a tyre wall the tyres are covered with render on the interior and covered by earth on the exterior (or cement render) so they are not exposed to sunlight, water, or air all of which tend to promote off-gassing.

Off-gassing from building materials such as plywood, carpet, paint, glue etc is more of a concern in a modern home. Thankfully Earthships are well ventilated bulidings and any off-gassing will pass out of the building quickly without the need for fans or mechanical ventilation systems.

Do tyres leach toxic stuff into water?

In an Earthship home, the tyres will not come into contact with water. An important aspect of construction is waterproofing and drainage of the tyre retaining walls and this ensures that water does not touch the tyres.

Tyres do contain toxic materials (just like the battery in your smart phone) however, generally these toxins stay in the tyre. If a tyre comes into contact with water that is highly acidic or highly alkaline which you might expect in a polluted environment such as a mine site then some leaching will occur. Even then, leaching of toxic elements out of tyres is minimal according to research commissioned by EcoFlex - a civil engineering company that builds walls and other structures with truck tyres filled with gravel and rock.

Finally, if you are worried about this issue you should consider the millions of tons per year of tyre dust particles that enter the environment because of cars and trucks driving about on our roads. Surely tyre dust floating about in the environment is far worse than whole tyres that are neatly hidden away from water, air and sun in a tyre wall.

Are tyres a fire hazard?

Not when they are filled with earth, built into a tyre wall and covered with render. Even un-rendered tyre walls have been known to withstand arson attacks in which they were purposefully set on fire. Even so it was easy to put out the fire because only a small portion of the tyre was exposed to air; the rest was surrounded by earth. In contrast, when waste tyres are stored in jumbled piles it is much easier for them to catch on fire because they have air all around (and inside) them and also the random arrangement makes it very difficult to extinguish the fire because it is almost impossible to squirt water onto all surfaces of the tyres.

How should I store tyres?

Try to keep them out of the rain so that the mosquitoes and rats don’t move in. Arrange them into stacks (about 5 or 6 high) based on tread width and then cover securely with a tarp, or ideally they would be in a shed. Try to arrange delivery of tyres “just in time” so you don’t need to have them on site for a long time. If you keep your construction site neat and tidy you will keep the neighbours and the building inspectors happy.

How long does it take to pound a tyre?

Depending on the size of the tyres about 10-20 minutes the traditional way with a sledge hammer. Make sure your “dirt” pile is nearby as it takes longer to pound a tyre if you have to walk a long way to get your tyre filling material.

A better question to ask is: how many tyres can I pound in a day (it's about stamina). You can use tyre pounding as exercise and it can be fun to pound tyres with your friends... If you have 10 people, pounding 10 tyres a day for 10 days you have your 1000 tyre wall done! With 50 people helping, which is not uncommon for Earthship Biotecture projects, you will have 1000 tyres pounded very quickly!

There are other mechanised ways e.g. using a pneumatic tamper as per rammed earth wall construction. People have devised all sorts of amazing machines to pound tyres. In general these machines focus on taking the labour out of tyre pounding although some time savings are often also realised. See the Earthship Jurien Bay webpage for an interesting tyre pounding innovation - the first YouTube video link.

Can I put sand or gravel in tyres instead of earth?

Yes you can, but of course you usually have to pay for sand and gravel. On the upside, sand and gravel require little or no compaction. Often gravel is put in the bottom course of tyres to augment the waterproofing and drainage system of the tyre wall.

Do tyre walls need reinforced concrete footings?

No. Earthship Ironbank proves this once and for all... although if you have highly reactive clay soil your engineer might insist on footings (Earthship Ironbank is built on moderately reactive soil). You should shop around for a structural engineer who understands the Earthship concept and this will help minimise or eradicate the need for footings and other expensive structural engineering elements.

Bottle Walls & Can Walls

What are bottle walls and can walls?

Glass bottles, plastic bottles and aluminium cans are used as a "brick" or "filler" in non-load bearing walls, typically internal walls and the walls at the ends of the greenhouse/sunroom.
The mortar around the bottles and cans is typically mortar (cement and sand) but cob (clay, sand and chopped straw) can also be used where weather proofing is not a big issue.
Bottle walls are labourious to build, very fiddly, but the effort is well worth it if you like colour and light... a bit like stained glass.
Can walls make less sense as the aluminium is actually very valuable and easily recyclable, but they can also be thought of as very cheap bricks which could be recycled at the end of the building's life.

Are bottle and can walls strong/structural?

Reasonably strong, but not advisable as a structural wall that holds up your roof. You can easily put load-bearing posts within a bottle or can wall.
The bottles and cans don't add any strength or insulative value. They are really just "filler" and "eye candy" which reduces the amount of other materials such as a cement and sand (or cob) that needs to be mixed and placed in/on the wall.
It is important that bottles (or cans) do not touch each other as it is the mortar around each bottle (or can) that creates a strong wall. 30mm-50mm of mortar is a recommendation.

do i have to use bottles and cans?

No. But if you are claiming to be building an "Earthship" you should think of an ecological wall material that uses natural or recycled materials or otherwise has a minimal carbon footprint.

Design

Do Earthships work well in all Australian climates?

Yes in most climates. Earthships, if designed correctly, can be expected to work well especially in the cold and temperate climates. Where there are overcast winters a small amount of backup heating will be needed. In the sub tropics and tropics it may be sensible to start modifying the design, but many of the Earthship design principles (passive heating and cooling) and goals (self sufficiency) remain valid.

Are termites and issue for Earthships?

Yes and no. They become an issue if the design doesn't address this potentially disastrous problem.

The National Construction Code (NCC) describes various approved methods to deal with termites (white ants) which eat timber and can cause structural damage to your home. These methods include barriers (e.g. stainless steel mesh), chemicals, and granular material (e.g. crushed granite). I don't believe it is realistic to expect a barrier system to be 100% reliable for an earth-sheltered home like an Earthship; because when you pile heaps of earth around your home it provides a lot more opportunities for termites to gain entry and start causing serious damage.

However, the NCC also mentions that if the structural elements (e.g. that hold up the roof!) are not susceptible to termite attack you don't need to provide a termite management system. My design approach is to ensure that all structural materials are not susceptible to termite attack i.e. termite treated softwoods, termite resistant hardwoods, masonry, concrete, steel and, of course, tyres. As a precaution, a "baiting" system can also be used to detect termite activity around the home, followed by chemical treatment (termite poison) if they are detected and seem to be a threat.

What type of floor can I have in an Earthship?

Usually you have a "thermal mass" floor such as concrete, earth or mud floor, pavers etc as opposed to carpeted or timber floors. Thermal mass floors help maintain stable indoor temperatures in cold and temperate and even sub-tropical climates. Personally I love earth floors. However, they are susceptible to damage e.g. to people wearing high heel shoes! But they can be repaired relatively easily. A more durable option is a concrete slab floor which must be sealed with a concrete sealer (preferably non toxic water based). You can grind and polish a concrete slab to make it look a bit more interesting or another method is to acid etch it or stain it with chemicals.

What type of roof can I have on an Earthship?

Earthship Biotecture (the company in the USA) has experimented a lot with roofs and seems to have settled on three designs:
- a skillion roof which slopes down to a gutter at the rear (e.g. the Encounter Roof),
- an earth-covered, vaulted roof made with ferro-cement (e.g. the original Simple Survival Earthship).
- a gable roof with north facing roof for solar panels (e.g. the Global Model Earthship) and south facing roof to a rear gutter.
The most important thing is that the roof is water-proof, well insulated and doesn't cause condensation issues.
An earth covered roof may help resist the radiant heat from a bushfire and also resist cyclonic wind forces.

I don't like tyres - can I use other materials for the walls?

Typically a tyre wall forms the main, retaining, wall at the rear of the earthship, adjacent to the earthberm. This retaining wall can be made with other materials such as:

rammed earth
sand bags (superadobe)
concrete block
pre-fabricated concrete panels
etc

It is likely that any durable retaining wall system will be suitable - but think carefully about what it will look and feel like.
And keep in mind that concrete has a large eco-footprint. Tyre walls are the most ecological.

why do some earthships have sloping windows?

Sloped windows makes a lot of sense in very cold climates because it minimises the amount of heat loss during winter nights while maximising heat gain during winter days. It also means direct sunlight gets onto the indoor garden throughout the year. The downside is extra solar gain in the summer which may not be a good thing in some climates (especially Australian climates).

A potential issue with sloped windows is that it may void the warranty of the glass or double glazed unit.

Increasingly, the Earthship Biotecture designs have evolved towards vertical windows - for simplicity of building and reduced cost.

The window angle is something to discuss with your designer/architect but if in doubt, vertical windows would be wise.

I don't like the look of earthships - can they look different?

Earthships generally need to have lots of glass to the north and the earthberm at the back (south) and ideally the sides too (east and west ends) (earthberm = the earth surrounding the building).

The roof style, colours, shapes etc can be quite conventional looking.

As for the internal finishes you can have very slick white walls if you want, or you can have wobbly, earth renders (or slick earth renders). It’s up to you how you want your Earthship to look although the basic "bones" of the building can not be changed - it is that way for a reason - uncompromising performance and sustainability.

Miscellaneous

Are Earthships built entirely with recycled materials?

No this is a misconception. They use a lot of recycled materials, BUT, you will almost certainly need to buy some new materials. If you are very resourceful you can salvage a lot of materials and save a lot of money. In bushfire prone areas you will need to have things like toughened glazing which can be difficult to come by second-hand and you can't cut it down to size.
You will need new cement and reinforcing bar for making concrete footings for the internal walls.
It would be wise to buy new roof cladding.
Plumbing and electrical gets buried or embedded in walls so new pipes and cables are a good idea. Second hand stuff may need testing.
Salvaging materials is time consuming and often requires a lot of work to prepare it for it's next life in your Earthship e.g. pulling nails out of salvaged timber; scraping putty out of floor boards. Also you need to store the materials safely and securely.
And these materials have to be designed into the building so, ideally, you need to have them before the design process is completed and submitted to council, or you need to collect exactly the right materials that are called for by the plans. It's not as easy as it sounds but it is very rewarding - do it!

How many earthships are in australia?

There are about 15 Earthships in Australia either finished or under construction.

Is everything I read about Earthships on the internet true?

Q: Is everything I read about Earthships on the internet true?
No! Reading through the various bits of misinformation on social media and the internet you will discover there are many people with a lot of prejudice about Earthships - they don't like them and their reasons for this are usually flawed or unreasonable.

The critique on Earthships at Architecture Republic is OK but, in my opinion, is a bit misleading in many cases. Also at time of writing this (March 2024) their webpage it is pretty out of date. For the most part it is correct although there are a few glaring inaccuracies:

it is NOT true that tyre walls are not load bearing and "some kind of timber or steel structure actually supports the roof".
It is also NOT true that blackwater is treated "within the walls" (they mean within the building). With the exception of a couple of experimental Earthships, blackwater always goes straight to the septic tank (which is outside the building).

There are many other issues with Architecure Republic webpage about Earthships.

There is also the book "Hacking the Earthship" by Rachel Prinz. This book is riddled with factual errors and misunderstandings about Earthships.