Welded wire sandwich panels were the framework and structural reinforcement for an adaptable concrete construction system selected by the Habitat for Humanity volunteer group's traveling work camp series in the summer of 1991. Working on 14 previously prepared foundation floor slabs, the volunteers installed 4x8-foot wall panels made of expanded modified polystyrene sandwiched into a lightweight three-dimensional steel truss and faced with welded wire fabric reinforcement. After the exterior panels were erected, door and window frames were set in place, and dry-mix shotcrete was applied to both inside and outside panel surfaces. Habitat used the same welded wire sandwich panel system to build homes in Tijuana, Mexico, in 1990.