Three Billion People, No Building Code

Approximately 3 billion people — one-third of the global population — live in buildings constructed from earth (adobe, rammed earth, compressed earth blocks, cob, wattle-and-daub). These building techniques are the most widely used construction methods in Sub-Saharan Africa, South Asia, the Middle East, and Latin America. Yet modern building codes — IBC, Eurocodes, and most national codes — either exclude earthen construction entirely or reference standards that have been withdrawn (ASTM E2392 was withdrawn in 2018 without replacement). Engineers and architects working with earthen materials have no code-compliant design pathway: they cannot obtain building permits, structural calculations are based on ad hoc methods, and insurance/financing institutions will not underwrite non-code-compliant structures. This code exclusion perpetuates a cycle where earthen buildings are constructed informally, without engineering oversight, leading to the seismic vulnerability that codes cite as the reason for exclusion.

Earthen buildings have the highest death toll of any construction type in earthquakes — not because earth is inherently weak, but because informal earthen construction lacks the engineering that codes would require. Modern engineered earthen construction (compressed stabilized earth blocks, reinforced rammed earth) can achieve adequate seismic performance, but without code provisions, these engineered approaches cannot be formally deployed. Meanwhile, 30–50% of global new construction in developing regions continues to use earth, entirely outside the code framework. This represents the single largest gap between building regulation and building practice worldwide.

Several national standards exist (NZS 4298 in New Zealand, IS 1725 in India, Norma E.080 in Peru), but they are not referenced by international model codes and are underutilized even domestically. The withdrawal of the only U.S. standard (ASTM E2392) in 2018 — for lack of a maintenance champion — actually moved backward. The CRAterre network has produced design guidelines, but these are advisory rather than regulatory. Attempts to incorporate earthen construction into Eurocodes have stalled because the committee structure requires material-specific testing protocols (compression strength, durability, seismic behavior) calibrated to the same reliability levels as concrete and steel — testing programs that have not been funded for earthen materials at the scale required.

A systematic material characterization program that produces the engineering data (characteristic compressive strength, Young's modulus, shear strength, durability under exposure cycles) needed for code committees to write provisions for the three most common engineered earthen systems: compressed stabilized earth blocks (CSEB), stabilized rammed earth, and adobe with seismic reinforcement. The testing program must use code-compatible methodologies (characteristic values at 5th percentile, reliability-based design) rather than academic averages. The key barrier is funding: code development is a public good that no single manufacturer will finance, and earthen construction has no industry association comparable to the Portland Cement Association or American Institute of Steel Construction.

A team could conduct a standardized testing program on locally sourced earth materials (compression, shear, moisture absorption) using code-compatible protocols (ASTM/ISO test methods) and compare results to the strength requirements in IBC and Eurocode. A team in a seismically active region could build and shake-table test a small-scale CSEB wall panel with different reinforcement schemes (bamboo, geogrid, steel wire) to generate performance data for code consideration. Relevant disciplines: structural engineering, materials science, geotechnical engineering, policy/standards development.