Hi. I am looking at building a greenhouse/aquaponics system - my first off the grid project. I have watched video after video of rammed earth tires and wonder, "Why not cut most of the sidewall off of one side of the tire and ram it with dirt?"
No more hand stuffing the sidewalls and swinging a sledge hammer at odd angles. It seems that the density can be achieved just as readily, that it actually fills the tire more completely, level it out more easily, and still provide as much integrity.
Am I missing something here? Probably, and that is why I am asking.
Tires are found to have some pretty noxious chemicals, they may be fine for a greenhouse but I would not want to live with them in general.
Cutting the sides is easier said than actually done, as that would be as much or more work than just using them as is.
If you do manage to get the tires cut with carbide cutting wheels or chainsaws you are going to change the structural integrative of the tire's normal geometry in such a way that it will not "pack" the same, nore provide as stable a wall/foundation assembly in general.
Bob Anders' advice is "spot on," and speaks to what I was saying about the maintenance of structural integrity of the wall system.
Bob Louis, advice will work but we found the chainsaw, or industrial shears are the fastest. With a sawzall, you can go through a lot of blades for an averaged size house project. Anyway you slice it, there is as much work in cutting up the tires as there would be in using them as is. It also does not address what Bob A. was getting at.
Thanks for the feedback. For clarification, since I left a lot out of my original post, here is some more:
The property is completely flat. The 5-6' tire wall would come up to ground level, and then have a cement pony wall on top of it to bring it to the height above grade that I want. The ground is entirely sand and rock - absolutely drains everything out of sight straight down. As far as we can tell, it is that way for over 400 feet.
The courses would be battered back 1.5" per course. This would let it act as a retaining wall against the outside materials.
Only one of the sidewalls would be cut out. The bottom one would be left in, and cardboard laid in it just like the standard rammed earth ones I have watched. See the pictures labeled Tire and Tire Cutaway
Rebar would be driven through the tires as shown in the courses attachment.
Also, I would screw them together as suggested.
Lastly, there is a tire recycler within a mile of me. I know some of the people there so might be able to get them to cut the sidewalls off for me for a reasonable rate or something. Otherwise I may be able to come up with something else to cut them, too.
Ok, with the drawings and description am I still off base here?
Looks good to me. And could not the removed sidewalls be tossed in with the fill?
I'm new to this. What is the cardboard for?
Just as a curiosity, the sidewall cutting I have done was to make homemade baskets for a disc golf course. I think disc golf is a great, low impact, way to integrate people into natural surroundings. We have a course that is in pasture lands, an alder grove, and mature second growth, mixed species, woods. In with this, I want to integrate a mushroom farm, greenhouses, and permaculture islands between the open field fairways.
"If we use our minds in a clear coherent manner, we will not accept the unacceptable."
The cardboard keeps the dirt from falling out of the bottom when doing the offset between courses. Here is a link to Youtube video that explains this. I am not associated with them, just one of the things I found for info. https://www.youtube.com/watch?v=cer3WKTOcy8
My reason for wanting to cut the tire is because it looks more labor intensive packing the tires, fighting the sidewall, then it does cutting the top sidewall (with the right tools) off. I think that I can get just as good of a pack, maybe even better, if I am not trying to kick the dirt in and then hit with a sledgehammer 50,000 times at varying angles. I am thinking a tractor with a tamper on a bucket bouncing the fill material down will work.
I was actually watching youtube videos on making sandals with tire treads and I found this video: https://www.youtube.com/watch?v=gE0GkBGyuZM which may be something fairly easy to construct, compared to other solutions...
Did you ever try your building plan plan by the way?
Would love an update on your progress. If you are doing a design in sketchup could you send me a "purple mooseage" found above. I would like to share some files with you and get a copy of your tire schematic. I have been doing some additional research per you questions and this post. I am going to reverse some of what I had previously said about chemicals (at least here in the US now...please anyone if you know of tire companies still using toxins in there manufacture let us all know) I actually found an old copy of the research that David L. referenced. If you are only cutting the top side wall you should be fine. You should read the research as you may find it informative. I am currently designing a timber frame that will sit on a tire foundation. Please keep us up to speed with your project.
I am aware that this topic is quite old, however such is the philosophy of permaculture - older is better... (replacing the latex protection on a fir-toothpick house every 5-10 years is hardly sustainable no?)
I recently completed construction of a device to cut the sidewall quickly - it consists of a large caster and several roller-blade wheels welded to some scrap steel - this hangs the tire in such a manner that it will spin freely in a relatively controlled rotation. There is then the Harbor Freight 6amp 1/2" drill attached to a hinge assembly via the side handle tapped holes. The drill drives a 12mm (~1/2") steel shaft supported in pillow-block-bearings. On the shaft, I attached a small motorcycle drive sprocket.
The tire is placed on the rack, and the drill is hinged down such that the drive sprocket pinches the tread between it and the large caster. Driving the drill then causes the tire to rotate. There is then a "carpet-knife blade" attached to a hinge, such that it pivots into the sidewall to be cut. It works great, and is my take on some youtube variations of tire-cutters.
I have noticed that the tire becomes a bit more wonky with one side-wall removed however, this is not a problem. The strength of a rammed-earth structure is the inherent compression strength of the fill material - the idea of the tire, or earthbag, or other wire/fabric is to provide confining pressure so as to prevent fracture planes from propagating - this whole philosophy is the concept of Mechanically Stabilized Earth (MSE), the concepts remain the same regardless of the specific mechanical material used. The somewhat wonky tire, when properly compacted, retains its round shape on account of the outward pressure of the fill. The lateral loading is well-handled by wall-system design (geogrid, tire connections, leveling, drainage, etc...) and is not strictly dependent upon the tire remaining whole.
Removing one sidewall to facilitate fill and compaction is quite ideal, and is demonstrated in the above two papers - you CAN use these papers to help convince an engineer if such is required for permitting.
For my own, my system makes use of the cut tire and 20ga chicken wire as a mechanical stabilizer/slope tie-back. I recognize that polypropylene or polyester mesh would be superior to chicken wire as my geogrid reinforcement however, cost is such an issue that it is either the wire, or a lot of prayers :(
With sufficient effort to level and compact the tire, and using the rope-ties outlined in the second paper, in addition to use of the cut sidewalls as further slope-ties and giving the wall a pyramidal-cross-section (bottom course is 4 tires deep, then three, then two, then one... again like the second paper) I see no reason why I should have any trouble.
My fill is decomposed hornblende-gneiss mineral soil (no organics) that holds a dry angle of repose of around 75 degrees - under magnification, it is very coarse/sharp, and when wet then compacted into a test-puc, it makes a very suitable solid mass.
Ultimately, I have no fear that this system (over 9 feet tall, and around 50 feet long) will be able to handle a concrete-truck driving on the area that it makes flat on my 30degree mountain slope.
Actually, using geogrid has a weird effect of becoming stronger under heavy load (crushes fill harder into the grid, making it more resistant to movement)
-----this is why nearly every earth-work in the US Interstate system is MSE.
So, for all that info -
YES, you can most certainly cut the sidewall of the tire for your GH walls, and more than this - YOU SHOULD - it dramatically reduces the time and labor, and there is no appreciable sacrifice in finished wall performance - if it can hold a concrete truck on a mountain, it will laugh at the piddly loading experienced by a GH or earthship.
Have a good day.
(P.S., this post is the result of a few months of research into the OP's question, because I had the same one.)