Moving in January, and planning on building Ernie a nice, big, new home. Treated wood is a bit pricey for us, and I know some other options are use clear-coat spray paint [and letting it dry out good for a couple days], or staple-gunning linoleum squares to the bottom/sides, or using a shower curtain along the bottom as well. What has worked for you guys? Whats the best/most economical/logical stuff to use to help waterproof?