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earth • ship - a dwelling designed to bring people into a more intelligent and sustainable relationship with their environment
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04.07.07   Plaster, Power, Insulation, and more

The following entry is a recap of progress that was made in 2006. I had gotten so busy that I was losing my momentum with the project and decided to hire out some help in order to save the work I'd done before the elements had their way with it.
The Plaster Shell:
For the plaster shell that shaped the roof of both structures, I hired a local man named Tim Parker who also does work for Earthship Biotecture and is familiar with the techniques the project requires. I bought some super plasticizing agent to add to the cement which helps make it more waterproof and easier to spread. The dome of the main building was previously shaped with a layer of cement-soaked fabric, which held up fairly well even when Tim had to climb onto the structure to apply cement to the top. Once the grey of the cement covered the shell uniformly and the brown coat was done, it really started looking good.
I had a hard time finding the right color for the final coat though. I didn't want to use the new stucco coatings because they contain acrylic which doesn't take additional cement very well, from what I understand. I wanted pigment to add directly to the cement, and the main supplier for this, El Ray, was phasing out the raw pigment product, or so I was told. The website doesn't appear to suggest this. Choices of colored pigment was very limited in my area, and they provided no examples of what the color looked like when dry. So I took a chance on the orange and while some seem to like it, it's not what I had in mind.
I purchased white cement to help keep the color from becoming too dead and dull, but that seemed to also make it paler, which I wasn't quite expecting. Also, the pigment looked much yellower before it was added to the cement, so I ended up with something closer to an orange sherbert than the more earthy ochre color I thought I was getting. This is one of those things that you best be on site for. Had I seen the batch in advance, I would have delayed this part of the project until I could nail down the color detail.
The cement for the roof of the power shed was a bigger problem. Apparently, the rebar arcs I had in place were not strong enough and not close enough together to carry the weight of even a sparing layer of cement without pushing in on the lathed structure. Again, had I been on site, I would have been inclined to stop and rethink. Tim did a good job of improvising the situation by letting the first layer dry and then filling in the sunken areas with insulation to save on cement, but it meant losing a significant amount of interior storage space due to the lower ceiling height.
Glass was pretty straightforward all around, including the sliding glass door, which fit very well and slid nicely. I used non low-e glass for the door based on some research in alternative building, but my solar guy tells me that low-e is better because while it deflects more solar gain, it retains what it takes in for much longer periods, which makes sense in the winter months when you spend longer hours in darkness. I used double pane glass for all other windows.
For insulation I was referred to a company called Warm & Fuzzy Foam Company, located in El Prado. I had them spray a generous 6+ inches at the interior top of the dome around the skylight and then taper down to 4 inches toward the bond beam. The stuff looks something like fat when dried. It's rather hard to control the flow of this stuff, and to predict how far out it expands, so forget about getting a nice smooth coating with no followup work. The unevenness means you may need to spot fill some areas if the desired depth is too thin, and to file back other areas that protrude too much. Remember to protect EVERYTHING you don't want to have to clean up later. This stuff is VERY tenaceous and sticks to just about everything except earth.
At about R-7 per inch, I am hoping this does the trick. We had a VERY overcast winter this year, and the overnight low temperature I was getting in the hut at first was only just above freezing! This however was prior to spot sealing leaks around the door with canned spray foam, plugging up the skylight for the winter, completing the thermal earth berm around the north side, insulating the bond beam on the inside, and adding insulated blinds. Plugging up the leaks, the skylight, and adding insulated blinds alone quickly brought the bottom temp up to a more normal low of 56 degrees. A completed earth berm and insulated bond beam will likely help to improve the performance even further. Also, there was a lot of moisture still drying out from the walls and floor. Moisture in an earth ship tends to make it feel colder for some reason, I've found. The dryer they are, the better they seem to perform in the cold.
The advantage to using the spray foam insulation over the batt insulation is that the spray insulation does not require you to build a double shell dome to hold it, and doesn't require a moisture barrier since the insulation presses right up against the shell and permits little to no air space where moisture could accumulate.
The disadvantage is price. I also had them add three inches of spray foam around the outer tire wall prior to beginning the berm, and in total I spent about $3000 to keep this little place warm. That's a big investment to be sure and one I might reconsider next time around. You can, for example, buy a foam insulation kit yourself and save a considerable amount of money by doing it yourself. Live and learn.
Solar Electric Power:
Getting the solar energy system installed was quite a momentous occasion. It really does something to bring a place to life, knowing it's there. It helps you feel more normal too, being able to do the things that most other people do. I like natural building, but I don't want to live in the stone age.
The 2 panels were mounted on a separate free-standing pole. The power board was mounted to an interior wall of the power and storage shed. It all works very well.
For the batteries, I dug an area into the ground in front of the power board and built a wood frame around it to support a cover so that you can stand directly in front of the power board over the battery box. I ran a pvc vent pipe from the box out through the roof but my solar guy tells me my pipe is too small (details details!). If you decide to do this, go with at least a 1" diameter pipe.
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related images (click to view photos in full resolution)
Plaster, power, insulation, and more
Plaster, power, insulation and more
A view of the hut with sliding glass doors. A view of the hut with sliding glass doors.
Another view of the hut with the glass installed. Another view of the hut with the glass installed.
Rear of the hut and power shed entrance. Rear of the hut and power shed entrance.
Looking up at the skylight with insulation fill around it. Looking up at the skylight with insulation fill around it.
My friend Russ installs the free-standing solar rack and panels. My friend Russ installs the free-standing solar rack and panels.
The solar power board. The solar power board.
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