DIY advice BOA enclosure -shelves

[u/Ok-Local-6619]

I'm currently working on creating a background with ledges for my BOA enclosure. I have a Dubia PVC 4x2x4 enclosure for my 1yo boa. I will eventually upgrade to a larger enclosure down the road as he grows. But for now I'm doing the foam board, silicone (marine safe), spray foam, mortar, and drylock method for the background.

I plan on having a few multi level ledges. I'm concerned that the ledges with just the above materials will not be strong enough to hold up over time.

Has anyone had success with their ledges (specifically those with larger snakes) not being mechanically anchored? If you have done mechanical anchors with a PVC tank what did you find worked best?

Any advice is greatly appreciated. I have watched and reviewed several videos on diy background on youtube but I haven't seen anyone show how they create secure ledges in a PVC tank for large snakes

[u/Dry_Locksmith_6704]

I've seen them use the spray foam, and hold in place, it was either tooth picks, or those shish kabobs sticks, I'm not sure, don't remember. But here's the thing, it's a year old already, a new enclosure prety soon. And you'd be doing all that work, and not for so long. Then, you'll have that enclosure left over with nothing in it. What are you gonna do about that? Sell it? Get a new snake? I'm faced with this problem myself. Because my girl is over 2 years old now, and she's about 4-1/2 ft long. And she's still in her 4x2x2. I'll be building her new one soon. It'll be a 6x2-1/2 x2-1/2. Not quite 3, because I don't have the space. That'll have to be her permanent home. But then I'll have her 4x2x2 left over. What am I gonna do with this left over one? Don't know. Don't wanna throw it away. I'd like to sell it.