Academy, Day 10

This morning’s class was a bit different. We had a double session of food production. Yes, it was all about all of the awesome things that have been and that you can grow in an Earthship. So far, space seems to be the only limitation. Having a huge apple tree might be difficult indoors. We got a nice handout with a list of a tonne of plants, both edible and ornamental that have been grown in an Earthship. It was quite extensive, so I won’t go through the whole list. But there were things like bananas (of course ๐Ÿ˜‰ ), pineapple, papaya, strawberries, lettuce, kale, tomatoes, cucumbers (many varieties), melons, carrots, garlic chives… and so on.

Michelle, the woman giving the talk, had quite the extensive knowledge and she went over many examples of things you need to do for certain plants to get them to bear fruit. For instance, bananas grow a main plant that will bear fruit and once it has done this, you rip that plant out because it will just sit there an rot after that. What will happen though, as it is fruiting, is it will pop up a few “pup” plants around its roots. You cut out the mother plant and most of the pups, and then let the last of the pups grow into a new fruit bearing plant. Groovy stuff.

After lunch, I was back working at the main build site. Today we were working on the concrete can wall form. This is a trench created over the top of the tire walls that will have the concrete bond beam poured into it. We need a bond beam that is 10 inches deep by 10 inches wide (25.4 x 25.4 cm). This is fairly easy work, except that I was working on the can work on the pony wall, which means constantly going up and down a ladder. Here is a picture of where we ended up.


We’ll continue that third course of cans to the end tomorrow. Here is a picture looking down into the trench created for the bond beam. You’ll also be able to see the rebar running through it for extra concrete structural integrity.


As we were working on the pony wall, we had to intersect this with the main back wall. Here you can see the detail of that. When the bond beam is poured, it will make one continuous piece of concrete over the entire tire wall.


Looking down the back wall, you can see how the can work continues. You’ll also see in the next picture, some wooden forms that are attached to the back wall. These are buttress forms that are housing more rebar lattice work that will also be filled with concrete. The engineer decided that these buttresses were necessary with such a long back wall, even though the wall itself leans into the berm at the back. It’s basically done for code compliance.


So, with any luck, the inspector will be out tomorrow to look at all the rebar work and then we can finish all of the form work with the cans and do the pour for the bond beam, the buttresses and the footings at the front.


Academy, Day 9

Another day, more Earthshiping ๐Ÿ™‚

This morning we covered grey water and black water systems with Mike Reynolds. The grey water system takes the water from your shower, bathroom sinks and laundry and sends it through a series of botanical cells. The plants in the cells feed off the water and help to filter it as well. The water that makes it through all of the cells is then collected in a tank and is used to flush the toilet, thus you are never flushing your toilet with fresh water. This saves about 50% of a household’s water use right off the bat.

The black water coming out of the toilet and kitchen sink head out to a conventional septic tank. Once processed by the tank, the effluent is then diverted to another botanical cell that will make use of all that lovely fertilized water. There is a conventional drain field attached to this as well, but almost no effluent makes it there because the plants in the botanical cell eat it all.

Unfortunately, like my other concept descriptions, I don’t have a picture or diagram for it, but I’m working on that. When I get some, I’ll update these posts.

After that, we had a class on how to read Earthship Drawings. These are the drawings produced by the architect and stamped by the municipality when the permit was issued. The real official things. They also gave us homework too. Each work group has to produce as complete as possible list of building materials required to make a simple global model one bedroom Earthship. They gave each group a set of drawings to pull apart to make the material list from. We have one week to finish it and the group that has the best list will get taken out for lunch. Pretty snazzy.

After that, we did the lunch thing and then it was back to work. Today, my group was working in a different location, not at the main build site. We were making bottle bricks. The first part of this is cutting the bottles. We wanted bricks that are 8 inches (20 cm) so, we cut the bottles at 4 inches (10 cm) and put two of them together. Here is a picture of some of my group mates cutting bottles using ceramic tile saws.


I cut bottles for a while; I tried a variety of bottle types and shapes to see how difficult it would be. Round bottles are definitely the easiest. After the bottles are cut, we need to rinse them out and then clean them, making sure the ends are clean so you can get the best light to come through them.


We also had to sort the cut bottle halves as you want to match a clear half with a coloured half, as this gives you the best light and colour combination. You also need to match halves that are the same size and shape. There are some pretty crazy shaped bottles. I cut one that was triangular and it will be impossible to match with anything but another bottle of the exact same type.


After you find two matching ends, you put them together and wrap some tape around them. Unfortunately, most of the ones we made we had carted away in boxes, so I just have a picture of two pink halves put together so you can see what a bottle brick looks like.


After we were finished making bottles, we headed back over to the main build site for the question and answer session. I took some pictures of the progress they made over there while we were off cutting bottles. Here you can see the rebar framework that was created for the footing that will go under the vertical greenhouse wall. The trench for that was dug out yesterday.


On top of the tire wall we will be pouring a bond beam of concrete. However, instead of setting up a wooden form for the pour, we use a can wall. A can wall is just aluminum cans embedded in concrete. This will make the form for the concrete beam. You can also see the rebar that has been pounded down into the tires to bind them to the bond beam after it is poured.


This last picture gives you an overall view of the site as it was when we ended today.


Tomorrow will be more can wall work and more prep on the vertical greenhouse wall footing. We can’t actually pour the concrete until the inspector comes by to look at all of the rebar work. That should be in about two days, we were told.

Academy, Day 8

We had Sunday (yesterday) off so I used that time to do my post about pounding tires. Today, it was back to the regular class in the morning and work in the afternoon.

We learned about capturing water from the sky from Mike Reynolds. This involves configuring the roof of your house to catch water, instead of shedding water. After that we did electrical systems with Phil. Looking at all of the components from the Photo Voltaic cells, to the charge controller, the batteries, the inverter and the breaker panels. We’ll be going more into detail with that later.

As for work, I started on finishing the tire work on the end of the pony wall. Here is a picture from the floor level.


And here is a picture looking down from the top of the wall. You can’t really appreciate the height because, of course, the picture is in 2D.


Here is a picture of two of my academy mates digging out the bed for the footing for the greenhouse wall. This is a wall of mostly glass that separates the main rooms from the green house. The outside stem wall is about six feet (2 meters) to the right.


We also had a wickedly windy day today. The weather authority here said there is a wind warning of 25 to 40 MPH with gusts up to 60 MPH. That’s 40 to 65 KPH with gusts up to 100 KPH for the metric minded. Anyway you look at it, it’s frikin’ windy, especially to be standing on top of a wall pounding dirt into a tire. I did have some precarious moments. This also kicks up a lot of dust and dirt. Here is a picture of my pack half way through the afternoon.


So, I made it through the afternoon, even after discovering the other tires already on the top course weren’t done properly, or maybe weren’t finished. So I ended up finishing all of those, plus adding the extra ones at the end. Then we added the lathe for the end piece pour, but we ran out of time, so the pour will have to happen tomorrow. Here is the state of the wall at the end of the day.


Tomorrow my group will be on a different work site, so I won’t see the finishing of the pony wall. The bond beam is going on top of the tire wall next, but I’ll likely be doing adobe finishing in one of the other Earthships that are being worked on. This is good, because there is a lot more to building an Earthship than just pounding tires.


So why are tires used, and what is this tire pounding thing I keep talking about? Let’s start with some conceptual stuff.

In a conventional house, when you’re building a wall that will support the structure, you need to put a footing under it. Usually this is a concrete pour that is about twice the width of the wall. So if your wall is 8 inches (20.25 cm) thick, the footing for that would be 16 inches (40.5 cm). This is to spread the load as the roof bears down on the wall.

Now, in an Earthship, we use automobile tires pounded tight with dirt to build the walls. Each tire is about 32 inches (81.25 cm) in diameter after it has been rammed with dirt. As you can see, this is already way thicker than the 16 inches of the conventional house. As a result, the tire wall can support greater loads and is its own footing as well. Here is a diagram showing the differences.


So, we have tires, and we want to fill them with dirt. How do we do that? First of all, we sort the tires into sizes. Ideal sizes are:

  • 235/75/R15
  • 225/75/R15
  • 215/75/R15
  • 205/75/R15
  • 225/70/R16
  • 215/85/R16

If you don’t know what those numbers mean, google it. Tire sizing is pretty weird. The R number is the rim size in inches, though, so we’re looking at 15 and 16 inch tires. For our purposes, we’ll start with 235s at the bottom and over the course of working our way up, end up with 205s on the top course. There is some mixing and matching to make it all work.

How do you pound the dirt into a tire? Well, let me show you. First you start with an empty tire and put a bunch of cardboard in it. Like this:


The cardboard is used to prevent the dirt from coming out the bottom as you move up the courses. You don’t need cardboard for the first course of tires. Once you have your tire in place, you start pouring dirt into it. At first you just work with your hands to push the dirt into the sidewall. Then once you’ve filled it as much as you can with your hands, you start to pound it with a sledge hammer. Thus the term pounding a tire.


It works best if you have at least two people to work on pounding a tire. One to do the pounding, the other to be what is affectionately called, the Dirt Bitch. This is the person who is there keep adding dirt to the tire as it is being compacted, keeping the one doing the pounding going. It’s pretty labor intensive, but if you have a partner where you can switch between being the dirt bitch and the pounder, it works out pretty well. After you have pounded the side walls pretty much as compacted as they can get, you take the time to level the tire, then you just pound in the rest of the dirt into the middle. The end result looks like this:


Here is a picture of me pounding a tire, just in case you thought I was making all of this up ๐Ÿ˜‰


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