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Title: Our Texas Earthship
Description: What we did right, what we did wrong


rdwzweb - April 26, 2006 04:12 PM (GMT)
We have spent the last 4 years building an earthship in west Texas (20 miles west of Abilene on a cattle ranch). I will spend some time tonight putting together some pictures.

We are completely off the grid. We do have a 250 gallon propane tank that runs the range and a backup space heater. At current usage the 250 gallons will last 9 years!

What we did right:

1. Put in a 10,000 gallon cistern for all water needs. Added reverse osmosis with water reclamation for the drinking water.

2. Used earth bags for inside planter and outside retaining walls (not wing walls though, those need to be tires.

3. Vertical glass. Much easier to build but sloped glass would be better in a northern climate.

4. Mud stucco on interior walls. Some earhen floors. Rest is satillo tile.

5. Did not pack out tires with mud - too much work - simply stucco lathed across the gaps and mud stuccoed.

6. Gray water processing system with inside front planter.

7. This was a lot of work but we wired for both 110VAC and 12VDC. We can run most of our lights, refrigerator and water pump on 12VDC thus reducing our energy consumption.

8. 700 watt solar electric. 1.5KW would have been better.

9. Solar hot water heating.

10 Staber washing machine and Sun Frost refrigerator.


What we did wrong:

1. Had a roofing company try to install operable sky lights on the back of a low pitch earthship with metal roof. They could never get them to stop leaking. So we had them removed and now we must cut windows in the back wall (we have about 16 inches between the top of the tire wall and the bottom of the roof i-joist.

2. Need to add cooling tubes in the back (we live in a hot summer climate).

3. Should have put sky lights in the front of our earthship where the ceiling is highest so convection will pull cool air through north cooling tubes and exhaust out front roof operable sky lights.

4. If sky lights had been in the front then leaking would not be as hard to fix because no massive build up of water.

5. Sun Mar composting toilet. This is very hard to get to work right. But since we do not have a lot of water we opted for this. It does not smell, however because we got the 12VDC exhaust fan). But I have had to manually shovel out the contents and get it started again and flies are an issue although malathiom quickly kills them without affecting the composting.

Charron - May 16, 2006 09:52 PM (GMT)
QUOTE (rdwzweb @ Apr 26 2006, 11:12 AM)
5. Did not pack out tires with mud - too much work - simply stucco lathed across the gaps and mud stuccoed.
This makes me a little nervous, though I'm thinking from the perspective of a strawbale enthusiast. (the 'plywood effect' of the concrete sheathing on the bales is what gives the wall structure its strength)

The air gaps that must exist in your wall would mean that you don't have as much tensile strength in the wall system as you could. I've been told by many sources that a tire wall is wobbly until it is reinforced with the surfacing and the berming. Have you noticed any cracking in your walls, possibly from movement? I don't want to be an alarmist, but like I said, this makes me nervous. :unsure: I'm pretty sure that here, where frost heaving is an issue, we wouldn't be able to do that.

QUOTE
5. Sun Mar composting toilet. This is very hard to get to work right. But since we do not have a lot of water we opted for this. It does not smell, however because we got the 12VDC exhaust fan). But I have had to manually shovel out the contents and get it started again and flies are an issue although malathiom quickly kills them without affecting the composting
I guess with your experience with a comercially produced composting toilet, you wouldn't recommend a 'humanure' system?

rdwzweb - June 28, 2006 04:42 AM (GMT)
First, the tire wall is not wobbly at all. The roof i-joist keep the walls from moving side to side and the clay packed tires are so tight there is no compression problem. There has been no cracking or movement.

The downside has nothing to do with strength, it has to do with thermal mass. There will be much less thermal mass since the packing of the tires requires a huge amount of dirt. Also the air pockets make the wall less effective at absorbing and re-radiating the heat. In our warm climate this is not much of an issue. For colder climates furthar north the tires should be packed out.

Second, I do highly recommend a 'humanure' system. These systems are emptied into outdoor composting basins and work very well. We actually have a backup toilet we built that uses the 'humanure' system. The have to be emptied often and smell if not vented.

Charron - June 28, 2006 05:12 AM (GMT)
I'm so glad you clarified. In our climate (Ontario, Canada) our summers are plenty hot, but our winters can be very cold. Thermal mass becomes a big issue for us in winter.

As for the Humanure system, I took the book out from the library ( a whole lotta techincal data, and some stuff I understood ;) ) so I now know the concept is something I am definitely going to encorporate into my home when I build. I will plumb in regular toilet hoopla for potential new owners, but for me and mine, the 'flushing' will be with aromatic cedar shavings or the equivelent. My father's traditional tomatoes will be extra nice because of it, I'm sure. :D

the three R's - June 28, 2006 02:03 PM (GMT)
this comment on the sky lights has me worried and wondering. I've heard so many people complain about the sky lights always leaking! I came across, and plan on using in my earthship something like this and I'm thinking it won't leak, but it seems to my recollection, that no one ship-owner, has ever seen or heard of these?! Is it the functionality of having them pull the warmer air out that you want? Because if so, I think I know of a company that makes similar ones that can open, but they're small like these are.

Am I missing something? Are you missing something? I don't know, please explain.

gatherer - June 28, 2006 06:06 PM (GMT)
those are suntubes basically .. and they shouldn't leak...

earthships are designed with skylights to allow ventalation of the interior... so they have to get operable. and with the lack of slope on the roof it makes it easier for them to leak. operable skylights don't leak when there is a large enough slope to the roof.




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