Patent for a building construction method. After completion of typical foundation and framework construction, "interlocking slabs or tiles are secured to the framework to form an outer covering or sheathing for the building." The interlocking method requires no cementing of material yet still allows water to be shed. "Provision is also made for fastening slabs or tiles to the framework in a manner permitting rapid assembly of parts" which reduces building time. The invention can be applied to doors and windows as demonstrated in the illustrations.