A pre-installation method for a shower base includes obtaining a combination of layers forming the shower base where the combination of layers includes a waterproof membrane mounting surface and a subfloor facing surface opposite the waterproof membrane mounting surface. The method also includes adhering, in a remote location from an installation site, a waterproof membrane to the combination of layers forming the shower base. The method further includes water testing, in the remote location, the shower base with the adhered waterproof membrane.