Wondering how rammed earth tire wall construction actually works? You fill each tire with dirt, pound it solid with a sledgehammer, and do it in the tire’s final spot, because a finished tire is too heavy to move.
This guide sits under our wider overview of earthship building, and covers the wall itself.
| Item | Value |
|---|---|
| Sledgehammer used for pounding | 8 lb |
| Weight of one pounded tire | Over 300 pounds |
| Typical crew per tire | Two people |
| Core insulation in a cited rammed-earth field study | 152 mm foam board |
These figures come from a builder’s tire-work guide and a Frontiers in Built Environment paper. They can change, so check the sources before you rely on them.
What a rammed-earth tire wall is
A tire wall is a stack of used tires, each packed hard with soil, laid in courses like bricks. Once rammed, every tire becomes a dense, heavy block of earth held in a rubber ring.
According to Wikipedia’s Earthship article, the outer walls in the majority of Earthships are made of earth-rammed tires. The same article says the buildings are often horseshoe-shaped because sharp right angles are hard to make with rammed tires.
The wall is not only a structure. Its mass is what stores and releases heat, a topic covered in our guide to earthship thermal mass.
Tools and materials you gather first
The kit is simple, and most of it is muscle and patience. Before the first tire is laid, collect:
- Used tires, sorted by size.
- Dirt, ideally excavated from the site itself.
- An 8 lb sledgehammer for pounding.
- Shovels and buckets for loading soil by hand.
- Scrap cardboard or empty cement bags, plus plastic for the first course.
- A level for checking each tire against its neighbours.
The builder guide says tire sizes are graded by height in the wall. In its words, “Large sized tires are used at the bottom of the wall, smaller sized tires are used at the top of walls.”
How to pound a tire, step by step
The method below follows the builder guide and the Wikipedia summary. The work is slow and repetitive, which is part of why a crew matters.
- Lay out the tire in its final position. A pounded tire weighs over 300 pounds, so all tires are pounded in place and are not moved afterwards.
- Line the bottom. Place cardboard or plastic in the bottom of each tire. On courses above the first, scrap cardboard or empty cement bags fill the holes and temporarily hold the earth in.
- Stuff in dirt by hand. One person shovels soil into the tire one scoop at a time.
- Pound the fill. Per Wikipedia, the other person stands on the tire and uses a sledgehammer to pack the dirt in while moving in a circle, keeping the fill even and avoiding warping the tire.
- Tamp the middle. The builder guide says to tamp the dirt in the middle of the tire after pounding the casing.
- Level it. Check the tire in every direction against its neighbours before moving on.
Laying courses and filling gaps
Tires are staggered from one course to the next, so joints do not line up. Pick one tire as a reference.
Gaps appear because tires vary in size. Builders handle them with “squishies”, which Wikipedia describes as tires rammed in between a tight space to even out the course or to compensate for varying tire size. This also cuts the amount of concrete needed.
Once a course is done, the cavities between tires are usually filled and the next course is set on top. Both faces of the wall are later buried or plastered over. The builder guide notes that this means any cardboard liner can decompose without affecting the rammed earth.
Is a tire wall enough on its own for comfort?
A tire wall gives you thermal mass, not insulation. Research on rammed earth in general supports this split.
A 2025 field study in Frontiers in Built Environment says rammed earth walls are valued for their thermal inertia but have low thermal resistance. It adds that uninsulated rammed earth walls are prone to significant heat loss, which limits their use in cold climates.
The study’s own wall used a continuous core insulation layer of 152 mm foam board.
Verify performance claims with a local engineer before you design around them.
Why the order of work matters
Because every tire is pounded where it will stay, the wall grows from the ground up, one course at a time. You cannot prepare tires elsewhere and carry them in, so the dirt, the crew and the tools all have to come to the wall.
That shapes the whole schedule. Soil has to be delivered to the working face by shovel and bucket, and each course must be levelled before the next one is laid on top of it. A tire that sits out of level is difficult to correct once it is packed full of earth.
Wikipedia’s account of the two-person method also explains why the pounder circles the tire. Moving around keeps the fill even and avoids warping the tire, which in turn keeps the course flat for the next layer.
- Start each course only after the one below is level.
- Keep the reference tire in view as you work along the wall.
- Use graded tire sizes, large below and smaller above.
- Fill gaps with squishies rather than leaving voids.
Sourcing and judging the evidence
Most step-by-step detail on tire work comes from people who build and promote these houses. That makes it useful for method, but it is not independent testing of comfort, cost or durability.
Wikipedia is a general reference, and the Frontiers paper discusses rammed earth walls. Treat any strong claim about energy savings with caution until a local professional has checked it for your climate and site.
Planning notes before you start
- Work as a team. The method is built around two people per tire, one feeding soil and one pounding.
- Plan the layout early. Because tires cannot be moved once filled, mistakes are costly.
- Think about the whole building. Water handling matters too; see our overview of the earthship greywater system.
- Check local rules. Building codes, permits and ground conditions differ by site. This site is independent and educational, and it does not offer design or consulting services.
Frequently asked questions
How heavy is a pounded tire?
Show answer
The builder guide says a pounded tire weighs over 300 pounds. Wikipedia gives up to 300 lb (140 kg). Either way, tires are filled where they will stay.
What do you pound the dirt with?
Show answer
The builder guide specifies an 8 lb sledgehammer, followed by tamping the middle of the tire.
Why are Earthships often horseshoe-shaped?
Show answer
Wikipedia says this is because of the difficulty of creating sharp 90 degree angles with rammed tires.
Do tire walls need insulation?
Show answer
Rammed earth research suggests uninsulated walls lose significant heat, which limits use in cold climates. Local conditions and an engineer’s advice should guide the design.
