Sod is the upper layer of soil held together by (usually grass) roots. It was used as a building material, in a similar way to soilbags.
Sod is the upper layer of soil held together by (usually grass) roots. It was used as a building material, in a similar way to soilbags.
Impermeable layer, usually skookum pond liner style, on top. Drainage. Ventilation and heating. Lime wash. Light helps if it can be managed in the design.