On the outside, we stained it red mohogany. Im thinking about going over the stain with a high gloss finish, so the end result would be much like the finish on a piano. For sealing the inside, we first painted with a marine type sealant, and then covered the bottom, and 2 feet up the sides with water proof silicone caulking. We used about 12 tubes of the stuff. The fumes are so bad when its wet that you have to run fans to circulate the air. After it dries, it is oderless. We've completed the enclosure all except for the trim work and the inside furnishings/ substrate. Ive already started putting dirt in, but am very much afraid that Ill need MUCH more dirt than I currently have. Im looking at roughly a truckload to get the job done.
I think for my next enclosure, Ill just line the inside with plastic sheets and seal the edges where they meet.
-Michelle