A method of generating a building assembly that includes spraying a coating material onto a plurality of pieces of substrate disposed on a first assembly face. The spraying includes spraying the coating material onto the plurality of pieces of substrate via a sprayer configured to apply the coating material to a target surface via a nozzle coupled with a mobile storage container storing the coating material, the coating material impregnating voids of the substrate. The method also includes allowing the coating material impregnating the voids to dry and harden and become rigid to generate the building assembly.