super basic question on tire filling: cardboard on the bottom?

I'm diving into a funny little side project of a root cellar dug into the side of a slope, and intend to use tire walls as the full front, and up the slope of the sides. This is basically an 8ft wide trench with a tire front wall.  Pretty simple stuff.

So I started working, and I'd never thought about it, but on the 2nd row of tires, when putting them staggered (like bricks) the hole of the new layer is not completely supported/covered by the lower layer, because of the edges of the tires below.

Now I start looking at youtube and I see people putting CARDBOARD in the bottom of the tires to hold in the dirt.  What?   What happens when that cardboard gets old and rots away?  is that ok because everyone plasters over their tires?

Is that the standard way to do it?  is there other ways?  if I do use cardboard, must I plaster, to keep the cardboard from weathering?

Tys

Tys,

Yes, to guarantee the dirt does not fall out the bottoms eventually it is best to plaster over the tires. Though it really depends on the soil used. I used high clay soil on a greenhouse with 7 courses and cardboard in the bottoms of the tires. (The first course or two should have plastic on the bottom below the cardboard as a water/vapor barrier). I never expect the dirt to fall out as it is nearly brick hard at this point. If you are working with sandy soils you can always put a layer or two of plastic at the bottom and double up on the cardboard.  Worst case, after a year or two you might have to pack out some of the tire walls if any dirt is falling out. If it is a root cellar I am guessing that would not cause a big issue.

If you have any more questions please let me know. I have a degree in Biotecture and building a full earthship inspired tire bale home this summer.

Bill

www.DragonFlyPrairie.com

I have no idea why cardboard is needed.
I lay the tyres down in columns, screw them together horizontally with roof screws.
Then I fill the wall with any scrap, I have used bottles , rocks and soil.
At the top I have made a mud mixture that can be formed into a water draining cap. The addition of lime or cement in the cap helps.

Am I clear in my description.
Tyres laid in the brick pattern are ok, but on a short wall you get lots of half tyre requirements which is not practical.
I have taken my walls up 6 feet.

I wouldn't use tires for that. Not unless you seal them in concrete.

Yuck. Stanky leachy...

For an above ground Earthship might be okay.

But you already started so try this: On the inside: slip form masonry:




I used to be a mechanic wouldn't want tire near my potatoes.

Where is the proof about toxicity of tyres please?

Bill Ayers wrote:Tys,

Yes, to guarantee the dirt does not fall out the bottoms eventually it is best to plaster over the tires.

Thanks for this explanation.  I can probably find this elsewhere, but how does one get clay plaster to stick to the tires?  Cover it with mesh?   Right now, I have tons of slaked lime, so I was planning on limewashing the heck out of the interior walls.

This root cellar will have a decent roof and being on a slope near the top of a mountain/hill, in the woods where it won't get horizontal rains,  I'm not too worried about water messing with it.  I will build in some drainage safety measures, but the wall itself shouldn't have trouble.

John C Daley wrote:I have no idea why cardboard is needed.
I lay the tyres down in columns, screw them together horizontally with roof screws.
Then I fill the wall with any scrap, I have used bottles , rocks and soil.
At the top I have made a mud mixture that can be formed into a water draining cap. The addition of lime or cement in the cap helps.

Am I clear in my description.
Tyres laid in the brick pattern are ok, but on a short wall you get lots of half tyre requirements which is not practical.
I have taken my walls up 6 feet.

I see how if you do columns you wouldn't have to worry about the half ends and the holes as they lay across each other.  I also like how you use trash to fill it up.  I've already started my project, so I won't be going the column route, but how do you deal with the meet points - where each column touches the next - isn't that a very thin point, possibly letting in air and weather?

I am not sure what the concern about the columns is?
Its not clear to me.

John C Daley wrote:Where is the proof about toxicity of tyres please?

Smell it.

With the tyre columns I create each column from the same tyre and size of tyre.
So each column nicely touches the other.
There are small gaps because of the curved edge of the tyres.

As for smelling tyres, fair call.
But, roses also smell, I need proof the smell from a tyre is toxic rather than just a terrible odour.