Abstract: A method for constructing a structure, preferably a swimming pool, includes the steps of excavating a cavity, applying a sub-base such as sand along at least a portion of the cavity, forming the sub-base into the desired shape of the structure, and applying a solidifier solution to the sub-base. The solidifier solution comprises a polymer in solution. The solidifier solution and the sub-base harden to form a smooth, hard composite layer in the base of the cavity, with the composite layer containing at least some of the polymer and at least some of the sub-base in a polymer lattice. After the solidifier solution has been applied, a liner may be installed, and the swimming pool may be filled.