A method of engineering monolithic earthen masonry consists of selecting sufficient amount of subsoil mixture and straws, wherein physical characteristics of the subsoil mixture are determined from a sieve analysis test and a hydrometer analysis. The proper mixing ratios of the subsoil mixture and the straws provide a composite sample. The composite sample is then dried and lastly exposed to a compressive test. If optimal plurality of particle size percentage distributions within the subsoil mixture is not obtainable due to lack of resources, the end-product of the non-ideal subsoil mixture is adjusted within the aforementioned method or thickness and/or height of a building to compensate for the load-bearing capacities of the building.