What Type of Tires?

What type of tires do people use for there tire walls? I have access to alot of heavy duty truck tires, but I am not sure if those tires would be to difficult to work with. Would passenger car tires be prefered over heavy duty truck tires?
Thanks,
Mica

Hi Mica. I think the problems you would run into using the larger tires would stem from the fact that the tire walls will likely be less flexible than those of passenger tires. But it depends on how you plan on packing them. If all you have available to you is a sledgehammer and wheelbarrow, I think that smaller tires would be easier to move into place (before you pack them, moving after they are packed can take a tractor, not kidding), and you either need to work under the tire wall or tamp through it, either way, the more flexible tire walls will win out, especially considering that you aren't packing just one.

I could be wrong, as I haven't actually done this stuff. While I like the idea of rubber-and-steel-banded masonry units, the approach seemed too labour-intensive when, using the same dirt mixture but making wall forms for rammed earth and using a motorized tamper (or a heavy-duty pogo stick with a tamping plate on the end ) you can get a more solid structure in less time and no off-gassing rubber under your cob or whatever.

-CK

You would traditionally use a 15" passenger car tire. The thickness ratio gets smaller as you go up the wall. Here is video that explains it better than me.


https://www.youtube.com/watch?v=EwTFRLv8grg


And as for the off-gassing behind the walls. . . personally I am more worried about radon. There was a study done by the University of Wisconsin-Madison, that found off-gassing only happens in piles exposed to the sun and weather. With no exposure to the sun, or air, or liquid water, there is no energy to cause the off-gassing. Fossils are made in such dark, dry, and airless spaces. The cover page of the study is posted on the Earthship site: http://earthship.com/offgassing



"A study could be performed in several Earthships of varying age measuring the byproducts of rubber degradation. These results could then be used to perform a risk assessment of the use of tires in Earthships. . . . In the absence of such a study, my personal judgment is that the risks of living in a properly designed and constructed Earthship are negligible compared to the environmental benefits of Earthship living."

Thanks for the response. This confirms what I already thought about using truck tires. Too bad though since I could have alot of truck tires delivered and dumped right on the site.

I might be wrong, but I have often thought that the whole process of tire packing might be made easier (and more readily sped up by even simple hand tools) by cutting or stamping out what would become the top wall of each tire, leaving a bowl shape with a hole in the bottom. This would speed filling and packing, and while you'd likely still need to make a custom-sized and shaped tamper, it would greatly speed the whole process, and let you make use of larger tires.

-CK

^^ There are already people that do that. It does indeed make it faster, but I would worry about the rim acting like the top and bottom of an "I" beam. The tires do seem to stretch more when I look at pictures of packed tires without a top.

One on the Earthship blogs out there has gone into using tires like this. I found a page detailing how they built a goat shed with topless tires. Lots of good pictures and a link to another topless tire study in the page. LINK HERE

Dear all,

I am planning to use from 195 x 15 x 70, downsizing till 165 x 13 x 70, the measures between the two are the most common down here, and I have already made my dogs house this way.

thoughts?

thanks,

Carlos from Uruguay

Thanks Brian. I was thinking along the same lines with regards to the sidewalls providing stability of form. I don't think it necessary to remove the whole of the upward-facing sidewall to make it easier to pack. I think a variety of steps could be taken to keep the tops from stretching out, and most measures I can think of as applicable would also increase lateral and quake stability.

-CK

I have been looking at tires at my local tire shop and I think that the low profile tires would work better for pounding / packing.
It would be similar to cutting half the sidewall off of a R75 tire. I think I can get 225 R50 16 tire fairly easy, this makes the tires about 25" across and the sidewalls are just 4½" wide.

MartinE

Hey Mica, I am also considering the rammed earth tire house with heavy duty truck tires. While some here prefer to use automotive tires, I would like to point out some pros and cons of using heavy duty truck tires.

1. Uniformity. While automotive tires come in sizes ranging from 13in to 16in (and higher,) each of those sizes has sub-sizes in them. If you go to a dump to get tires, there is alot of hunting involved to find all the same size and then strategic placing of tires to keep from having gaps. In your heavy duty truck tires, the majority of your tires are 11R 22.5, Low Pro 22.5, 11R 24.5 and Low Pro 24.5, so there would be alot less hunting involved to find uniform size of tires.

2. Larger size. Since HDT (Heavy Duty Truck) tires are about twice the size of automotive tires, it would take less tires to build the structure. Since the tires are wider, you could run less courses to achieve the same structure height and because the center opening is larger, you have more room to maneuver a backfill tamper which would greatly reduce the amount of physical exertion or if you use a sledge hammer, it gives you more to swing it. Also, the larger size tire gives the wall a much larger footprint on the ground for more stability.

4. Thermal mass. Most people building these homes are doing it for the reasons outlined in the Earthship concept. since a HDT tire is larger, it provides more thermal mass.

5. Upper assembly. Since the center hole is larger, it would be easier to get your rebar through 2 or 3 courses of tires when you are ready to pour your bond beam.

On the downside of using HDT tires....

1. It would take much more earth to fill an HDT tire than an automotive tire.

2. It would use alot more material to pack out the interior walls to make them smooth

3. Where and automotive tire would weigh in at around 300lbs. A HDT tire would probably weight about twice that amount. So while you can make minor adjustments to an automotive tire after packing it in place, this would be much more difficult with an HDT tire.

Now all of these cons add thermal mass to the walls which improves your heating and cooling effects.

Someone had mentioned a heavy duty tire wall would not be as flexible, I don't really see that. It would be just as flexible, have a wider and more stable base, and the casings would be stronger. Of course, all that only matters if you are building your home in an earthquake prone area where a house needs to flex. I have also seen places where some people cut the top sidewall out to make packing easier. If you are thinking about doing this, you need to consider how concerned you are about lateral stress or shifting ground on the home. If you are sure your site is stable, it is probably OK. Again, if you are worried about earthquakes or have other reasons to be concerned with the stability of your site, then you should leave your sidewalls intact. As a personal preference, I would leave the sidewall intact. A few extra hours of labor, sweat, blood and bruising would be worth the mental security over the lifetime of the home.

Now I am a newbie here, and also a newbie to the tire house thing. I stumbled on it about 2 months ago and have been pretty headstrong on it since. I am still in the planning stages of my new home and I am probably suffering from a bit of tunnel vision. So if any of you out there have some insights I need to be aware of, please let me know. Thanks!

It depends on where your house is located. If it is located off a long dirt road or the middle of nowhere I would use off road tires, but if it is next to a road or in the city I would think road tires would give you a better house.