My husband, sad over the recent passing of his beloved 13 year old Basset Hound, Molly, decided to build a koi pond in her memory. He'd never built a pond before. We did some research and decided to use landscape timbers. We bought a pond liner first and then built the outer dimensions to coincide with the liner dimensions. He used carpet reminents to line the bottom of the pond and then bought an in-expensive roll of attic insulation and lined the inner edges. Then he added the liner. He used an extra row of landscape timbers on top to help anchor down the stapled liner on top. We added water, a fountain bubbler and a "spitter." Here is the end result. I think he did a great job! We still plan to add pond plants, koi, stain the wood and add plantings around it.