After tamping each earthbag course flat and level, lay two strands of barbed wire along its full length before placing the next course, so the barbs grip into the bags above and below and lock the courses together. At corners, bend the wire around the corner and extend it at least 50 cm along each wall face to tie the two walls into one structure.
Part of Earthbag Building
Wire between courses is the tension element of an earthbag wall, laid after tamping and before the next course.
Wire Goes On After Tamping And Before The Next Bag
The sequence matters. The course is placed, tamped flat and level, and only then is the wire laid on top of it. Bags laid above press the barbs into the fabric on both sides, which is what stops one course sliding over another. For what the wire is and why it matters, see Barbed Wire and Alternatives.
What You Need
- Barbed wire, 4-point, enough for two strands per course.
- Wire cutters and pliers, heavy gloves, eye protection.
- A means of holding the wire down while you place the next bag, such as a few spare bags or stones.
Method: Lay, Corner, Cover
Step 1: Check the course is flat and level. Wire laid over a lumpy course is lifted off the bags.
Step 2: Lay two strands along the full length of the wall, spaced apart across the width of the course so the wire is not stacked on one line.
Step 3: At corners, bend the wire around the corner and extend at least 50 cm along each wall face. This ties the corners together structurally.
Step 4: Join lengths by overlapping the ends and twisting or lashing them together, and place the joins at different points in successive courses, so no join lines up above another.
Step 5: Place the next course over the wire, offset by half a bag, and tamp it; the barbs bite into the fabric.
Common Mistakes
- Skipping a course. The wall then has a slip plane at that level.
- Both strands on one line. The rest of the width has no wire.
- Splices stacked above each other. They create a weak vertical band.
Safety
Barbs and whiplash
Wear heavy gloves and eye protection. A wire pulled tight can slip and lash, and a coil cut under tension springs back. Keep wounds clean and keep tetanus protection up to date if you can.
What’s Next
- Learn next: Window and Door Framing — wire around openings
- Combine with: Tamping Technique — the step before the wire