Methods are disclosed for making a base of a spa apparatus to resemble artificial rocks and wood. In one embodiment, the method is comprised of the following steps: making a mold in which its inner surface has the shape and surface texture of a rock or wood; placing a first structure on the inner surface of the mold, the first structure being operative to prevent warping of the base; spraying polymer on the mold; allowing the polymer to harden; and removing the hardened polymer from the mold, the hardened polymer having substantially the shape and surface texture of rock or wood.