Building a tire wall.

Factual Questions
1

I am considering using discarded tires (free material!) to make a low wall to fence a lot. It would be about 4-5 feet tall. What do I need to know?

Googling takes me to all the spaceship home sites where they cavalierly gloss over all detail.

How solid would these walls be? It seems that the roof is somewhat important to spaceship homes, but mine will be a free standing wall (and mostly straight, so no curves and corners for added stability). Will the next tropical storm knock the whole thing down? Is there any way to reinforce them beyond the packed dirt inside?

Also I would like to plant flowers or whatever on top. Any special considerations? Will the soil dry super quickly?

What’s the best type of paint to paint one of these walls?

2

Check your local laws. Tires may not be free. They may have recycle requirements.

But you’re probably fine if you’re using them, even if not for the intended purpose.

You will need additional structural support to keep the tires on top of one another. Rebar should be sufficient.

The dirt “mortar” will be highly suceptible to erosion factors like wind and rain.

3

Tires tend to collect water and become mosquito breeding places.

4

The tires are filled with packed dirt, so they are not collecting water inside. And the dirt is not really acting as mortar, it just sits contained in the tire to make it heavy, which is how I understand they gain stability.

I was thinking rebar or wooden stakes vertically going into the ground to affix it, but wondering if it is unnecessary and how much are they needed if at all.

5

Why not stack them up the fill them with concrete?

6

Concrete is very expensive (about $276 CAD per cubic meter here last I bought). Clean fill is often the cost of hauling, or is free if there is an excavation going on close by.

I assume the tires are stacked and filled vertically and there would need to be some structure to provide lateral stability between the cylinders. I picture two rows of tire ‘cylinders’ with vertical and horizontal rebar. Buried plastic mesh is sometimes used to tie back retaining walls. Plastic mesh between tire layers and vertical rebar would probably do the job.

7

Vertical cylinders won’t work.

Lay the tires up in running-bond fashion, like a brick wall. Start by laying out one row of tires on level and undisturbed earth, and pack them full of dirt.

For packing, sandy soil works best; aggregates are okay; clay can be problematic. Remove all organic materials like sticks and roots, so that they don’t rot away and leave voids. Pour the dirt into the tire from a bucket, then stand in the tire and with your booted feet, kick the dirt into the rim. Add more dirt and keep kicking. As the tire fills, switch to an eight- or ten-pound sledgehammer and pound the dirt into the rim of the tire. Eventually, the tire will be solidly-packed. This takes a surprising amount of dirt.

Lay the second row of tires across the gaps between the first row. Place cardboard in the bottom of the tires to block the openings. Pack these tires with dirt as well. As the tires are packed, they will swell vertically and become slightly narrower horizontally. As the wall is completed, the tires will lock in to the tires around them: their shape, weight, and the friction of the rubber will keep them from moving easily.

The top rows can be fastened down by pounding rebar vertically through the tire sidewalls where they overlap. For house walls, we passed the rebar through holes in a sill plate and bent it over to fasten the sill plate down (some details omitted). Some people build a continuous reinforced-concrete bond beam across the top of the wall, and tie the rebar into that.

For houses, these walls are generally only built 1 storey tall. Tire walls more than ten feet high can be problematic. Lengths of straight wall of more than 12 feet or so require lateral bracing, either through corners, buttresses, or connected beams or rafters. The original house designs as promoted in Michael Reynolds’ Earthship books used a single row of rooms, with horizontal arches at one side resisting the earth pressure of a berm, with straight dividing walls acting as buttresses to the arches and laterally braced by roof beams.

We covered the walls with concrete parging, using pop cans to occupy space and reduce the amount of concrete required.

This technique is kind of overkill if you’re just building a fence, unless you’re trying to restrain rhinos or something. We did use it successfully for a retaining wall though; there we stepped the tires back.

8

Thanks for the detailed response. I do agree that the tire wall might be overkill, but we are hoping that the fact that it is basically free and that it is a bit of a green thing to do using something that would sit forever in a landfill will justify it.

12 feet before needing bracing is an awfully short distance, though. Although our wall will be a low one (4-5 feet tall) and that might make it more stable. Some form of folding might provide the necessary corners for added stability.

I would like the wall to be naked (just the tires on the outside) to highlight the fact that we are reusing tires. Is there an elegant way to handle the ends where you have half tire holes?

9

In house walls, the half-tire spaces are filled with concrete in cardboard boxes. This is okay, because the whole thing will be covered by layers of parge.

I would not recommend leaving the tires exposed; this makes them vulnerable to UV degradation and fire, which they are protected from by the concrete outer coating.

10

How much of an issue are UV degradation and risk of fire for a stand alone low wall that is not part of an enclosed building? Would painting them help with the UV?

11

I don’t think they would be a huge problem. Painting them would help.

12

Building tip here

Most of what I’ve seen of used tire based construction/landscaping that was exposed to the elements or dirt filled for stability did not turn out well in the end as tires are relatively light and flexible and tend to work loose over time from whatever earth/dirt/wood material they are embedded in (short of being filled with concrete).