RTB enclosure building materials & hide size

[SaDel]

I have a male RTB, named Apohis, that I got about a year ago. He is about 3 1/2 to 4 inches thick at his largest part. I think he is about 5 feet long. I don't know how old he is because he has been passed from home to home many times. I felt sorry for him and adopted him, and the person I got him from didn't know much about him. He hasn't grown very much in the time I've had him.
So I want to know how much bigger he might get, or if he is about as big as he will get. I've been hearing that he will get almost double the size he is now. Is that true? My dad & I are planning a new enclosure for him. The planned cage size is 4 1/2 ft long, 5 ft high, and 2ft wide. (He loves to climb!)But I need to know how big of a hide he will need at his biggest size. Right now when he curls up he takes up about 1ft by 1ft of space.
We were planning a fairly elaborate set up with two shelves, a ramp, and a tree with branches. We were going to make the walls & shelves look like a rock formation. So we were thinking about making the shelves out of wood with a thin layer of concrete smoothed over them to make them look like rock.
For the tree we were thinking pvc pipe coated with dyed concrete or paper mache and a coating of sealant. But I'm worried about these ideas because I don't know what sort of things are toxic to snakes. I'm worried that any concrete dye would be bad, as well as any type of sealant we might use. I figured that the plain concrete would be fairly safe, but if I'm wrong I need to know. What types of materials can I use to make the faux stone & tree, but not be toxic to the snake?
If these things won't work, then that probably means that paint would also be toxic, right? If I cannot make the faux rock & tree, then what sort of wood should the floor of the tank be make of? Obviously it has to withstand moisture. And if the tree is not possible, what other sorts of things should I use instead, and do you have any ideas where to get them? Fake vines at the pet store are ridiculously priced, so I'd rather go cheaper if possible.
Sorry this post is so long, and thank you for your help. I don't want to hurt my snake.

[scink]

-The flooring can be made of rubber, purchace a roll of "rubber paper" (not sure of the real name), used for roofing, then you can make a sort of brotective bowl aound the bottom of the enclosure then seal it with black caulk. This creates a waterproof floor for you. Then use whatever substrate you choose.
-For the tree the easiest(pricier) thing would be to purchace a few peices of driftwood. Or just cut down a tree limb to your liking, sand it down and finish it. As long as it is completely dry it wont harm your friend.
-As for the concrete i was a mason so my advice would be to cover the wood in tar paper staple it, then cover that in wire mesh and staple it, then spread the concete over that. If you want to make the rock look more like a rock you can put the wire mesh over pieces of foam to give it some shape. Good luck!

[mhartmann]

Just about every care sheet and manuel for keeping captive boas will say that boas will grow to their maximum possible sizes, so they say the adult size will be 10 ft for a columbian boa, etc. There's good reason for this as so many people give their snakes away when they get 'too' big, and many snakes then can't find homes, it's terrible. But truth be told, there may exist one male columbian boa in all the world that makes it to 10 feet. That's huge for the size. I'd put money on it that your male boa will not grow much larger (although all boas continue to grow throughout their lives, this is in really small amounts). I imagine your boa will probably grow another 6 inches in the next 10 years. Of course i could be wrong, but if you look at statistics, the average adult male columbian boa is between 5 and 6 ft. And I might err on the smaller size for you taking into consideration the number of owers which means there's a high probability of not optimal care during that time (they grow differently according to feeding and temperature regiments etc.) So your cage sounds big for him, but then he'll probably be the happiest boa in all the land with the care you're putting into it. But it might be a good idea to make the hiding spots removable so you can change sizes if you need to, for ease of cleaning, and to better get at your boa for handling times. My two cents.

[razeraze]

Plan for your snake to get bigger than the largest boas recorded, then you never have to be between a rock and a hard space should it out grow the normal sizes.

Also are you 100% sure yours is a male? I have had my boa for 6 years next month and have never had it sexed. Because of her size I am assuming she is a female but there are some large males out there.

I would make the cage longer, 6'L x 3'w x 5T sounds great. Keep in mind many people house full grown boas in cages smaller and/or shallower but If you want to go big that is what I recommend. Our boa lives in a slightly taller cage than that.. It is constructed of medium density fiber board (mdf) and wrapped in 30ml pond liner. Here are a few pictures of the cage, the round black bowl is a barrel liner for a water dish.




For the rock wall. You can find many ways of doing it all over the web, My advice would be a mortar or a fiberglass and sealed with a polygem dino goo epoxy.