Human Brute Force Yields Stellar Density Testing Results!
Thanks so much WDTN Channel 2's Tara Hastings for including a story last week on our Earthship build! It was cool to see our story played out in the news and Elliot loved watching us on screen and in person at the same time :). Check out the video here.
While this type of home takes care of you once built, there is a good chunk of change that goes into the initial phases of the building process as the systems and their components (water harvesting, supplemental heating, etc.) are all purchased and installed in the beginning stages before the berm is built and the slab is poured. Once things slow down a bit, Zac and I plan on sitting down to discuss our budget and what we need to do to meet our goal for this winter.
In other news, I realize that I never revealed the results from the density testing of the pounded tires we completed per the County's request the first weekend of the build. They requested that we have a proctor test done on the soil we'd be using to compact the tires with and then wanted density testing samples taken from a few tires to ensure that we were achieving between 90-95% compaction rate. Per Wikipedia, a proctor compaction test "is a laboratory method of experimentally determining the optimal moisture content at which a given soil type will become more dense and achieve its maximum density."
While our original plan was to use soil from our site to pack tires with, after delivering a 100 lb. sample of our soil to the geotechnical engineering firm, they were able to take one look at it and see that there was far too much organic matter (decomposed plant and animal matter) in it to use in our Earthship build. The issue with soil high in organic matter is that it is too loose and fluffy to compact well. The best soil, we've been told, is a combination of clay and sand. Thus, instead of digging down further on our land to obtain the mass amounts of soil we were in need of, we called a local soil/gravel/sand supplier and were able to get the "junk" soil we were looking for (Note: We are noticing a running theme with the build of this home. It seems everything that others don't want or consider to be "junk" is just what we need to build our Earthship... "junk" tires, "junk" soil, etc.).
They dropped of 60 tons of dirt the first weekend and 60 more the next. We still haven't gone through much of the 2nd pile so if you're wondering, it took about 70-80 tons of dirt to fill about 230 tires... that's a lot of dirt! The engineers said that this soil was just what we needed for our home build. We were told by the company performing the testing that they would be shocked if we would be able to achieve this rate of compaction by hand (with sledges) though we ensured them that it has been done time and time again by others building this type of home.
The local geotechnical engineering company we used was fantastic and allowed us to borrow equipment to obtain the samples ourselves to save on costs. We were to take 3 "core samples" from completed tires. The tests were performed by taking a long metal tube (AKA, a shelby tube) and driving it into a compacted tire to take a sample of the compacted soil within. In taking one of the three samples, the shelby tube slipped but we didn't think it would impact the test so we continued on and delivered the samples we obtained to the lab. The results from the tests revealed that on 2 out of the 3 samples, we achieved a 96% compaction with human brute force alone (take that machines!). The test where the shelby tube slipped showed a 75% compaction rate. We may have to redo this sample, but have no concerns whatsoever that we will be able to achieve the needed compaction rate time and time again!
In moving forward with the build, we are still working to fine-tune some details to ensure we are doing things from here on out the right way. We have had to redo some things completed in the first weeks as we were operating off of advice given as opposed to professional design direction. Some of these changes have been time consuming so we want to make sure we are careful and purposeful from here on out as this is to be our home until our dying day. With that said, however, we are still working away each and every weekend and would LOVE to have anyone interested lend a helping hand and at the same time, learn the skills to build an Earthship! Just shoot me an email if interested in volunteering and we can register you for any and all weekends you'd like!
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This past weekend, we were able to complete the french drain in the back of the home and nearly finished off the 3rd course of tires! Now, the 3rd course must be leveled and the other half-tires (tires that are cut to fill the gaps between tires that naturally arise due to inconsistent tire sizing. These gaps are then filled with concrete) completed. As I mentioned in the last post, Zac and I are really working to reframe the way we are viewing our home build. Initially, we were all for an aggressive timeline, but we quickly realized that in order for us to enjoy this process, make the most of this experience, and build a structurally sound home, we need to take it a day at a time to truly enjoy the ride and ensure that everything is done correctly. Our general goal though is to be under-roof by winter so that we can spend the cold months working on the interior finishes. It doesn't seem as though this goal will be a stretch and the only real limiting factor we could see impeding this goal would be finances.
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| Zac taking a core sample of a compacted tire |
In other news, I realize that I never revealed the results from the density testing of the pounded tires we completed per the County's request the first weekend of the build. They requested that we have a proctor test done on the soil we'd be using to compact the tires with and then wanted density testing samples taken from a few tires to ensure that we were achieving between 90-95% compaction rate. Per Wikipedia, a proctor compaction test "is a laboratory method of experimentally determining the optimal moisture content at which a given soil type will become more dense and achieve its maximum density."
While our original plan was to use soil from our site to pack tires with, after delivering a 100 lb. sample of our soil to the geotechnical engineering firm, they were able to take one look at it and see that there was far too much organic matter (decomposed plant and animal matter) in it to use in our Earthship build. The issue with soil high in organic matter is that it is too loose and fluffy to compact well. The best soil, we've been told, is a combination of clay and sand. Thus, instead of digging down further on our land to obtain the mass amounts of soil we were in need of, we called a local soil/gravel/sand supplier and were able to get the "junk" soil we were looking for (Note: We are noticing a running theme with the build of this home. It seems everything that others don't want or consider to be "junk" is just what we need to build our Earthship... "junk" tires, "junk" soil, etc.).
They dropped of 60 tons of dirt the first weekend and 60 more the next. We still haven't gone through much of the 2nd pile so if you're wondering, it took about 70-80 tons of dirt to fill about 230 tires... that's a lot of dirt! The engineers said that this soil was just what we needed for our home build. We were told by the company performing the testing that they would be shocked if we would be able to achieve this rate of compaction by hand (with sledges) though we ensured them that it has been done time and time again by others building this type of home.
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| Hole left from density testing |
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| "Junk" = Home |
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