Giving Zeus an addition to his home

So I have my Bp set up in a 20g breeder tank, but zeus is starting to outgrow it. I had an idea that I think will be pretty simple to do and should give him a lot of room.
What I plan on doing is taking the bottom piece of glass off of his current tank and building a plywood box with the same lenght and width of his current tank and only about 6 in high or so. I would put his bottomless tank ontop of this new box with holes in each end so that he can get down into it and back out of it. So the top of this new box is now the bottom of his current tank. I was planning on puting in dividers to section the bottom off into three chambers that he could move between. So basically the new box would be like adding another level to his current cage that is completely dark. The new level would serve as his hides and would probably retain humidity better than his glass tank does. The front of the new level would have hinges on it to allow me to clean it out.
He would have all of the room he has now plus I would remove his hides from the top tank so he would have even more open space (filled with stuff to climb on and through). And then he would have the same amount of floor space down bellow that is dark to move around in.
What do you think? Has anyone done anything similar? It seems like the best of both worlds, he has dark space to enjoy and I get to see him if he wants to come out and wander around the glass upper level.

The biggest problem I see with that is wood retains moisture which means it will retain bacteria. I would just wait a little while and find a shop that sells leaker tanks and just get him a bigger tank.

Hmm, okay. Well what can I do to prevent wood from retaining moisture? How big of a problem will it be? I really want to try this because I have the materials and tools (ok, my dad does and I'm just going to take them) and it won't take much work to build. I really don't want to go buy a tank, and I don't have space for anything much longer than what I have. Thats why I figured that adding a new level would be the way to go for me.

Most people that build their own tanks from wood either use moisture sealer and I have seen some use melamite sheating that they iron on. But since yours will be on bottom I think that is out. My best guess would be to try the water sealer

Thanks. What about rustolium indoor/outdoor spray paint? I read thats pretty water resistant. I was going to paint the whole thing black anyways. Is that toxic at all if I make sure its really dry before I introduce my snake?

Once it's dry it's fine. That could take several days in a well ventilated area, more depending on humidity. I wouldn't use a spray paint though. Without priming first, the wood will soak up the paint until it's saturated so it could take several coats to get a good barrier. You could spray primer then spray paint but there's something easier now. Behr makes a paint/primer in one, their Ultra line. Get a quart of semigloss exterior in the color "Beluga". It's 3oz of black tint into a deep base quart. One coat of that and you should be good to go.

One other benefit to the Behr paint is that it's low-voc which means it has less odors to begin with.

Awesome, thanks a lot. I'll go that way then. You guys are great.