"Great Stuff" spray foam coated in silicone for tank walls

[Bogertophis]

Here's my thoughts on this:

The only silicone* I'm familiar with is that sold specifically for sealing the corners of glass aquariums- and once it's completely dry (with NO off-gassing) it's safe for herps. I would be very cautious to read the fine print on any other formulations of silicone that are made for purposes other than live animal-keeping. Note- silicone aquarium sealant can take "forever" to dry completely IF it's applied thick- the "inside" doesn't dry well & off-gases irritating vapors for a long time unless it's used sparingly so it can truly dry. (*The silicone stuff they're showing is made for use with a caulking gun- cannot vouch for it being safe.)

As far as a snake ingesting a bit of fully dried silicone, I think they'd be unable to digest it, so as long as it was small enough to pass easily, I think it would do no real harm & you'd "be seeing it again some day" when it's passed in the stool. Larger pieces could cause an obstruction though.

I can't speak for the expanding foam, as I've no experience with using that- I think some others have, but again, plastics & similar materials tend to off-gas unhealthy things- & with the reduced air flow practiced by most BP keepers, just keep in mind that snakes are far smaller, delicate & susceptible to chemicals than we are, which they'd be forced to inhale "24/7". Our own sense of smell is not as good as a snake's, so I'd say if you can smell it at all, never expose a snake to it. The same goes for any furniture finishes which I can guarantee are mostly toxic to snakes. Any paints used for pet enclosures should be "No VOC", & while harder to find, they do exist. ("VOC" = volatile organic compounds- That refers to chemical vapors that may continue to off-gas.)

I'll admit that such naturalistic backgrounds are wonderful to look at, & probably enjoyed by the occupants, but what concerns me is that there's no way to really clean all those crevices. For disinfectants to be effective, the dirt & debris needs to be removed, & "good luck with that" in such an enclosure. My personal preference is keeping decor very simple, washable, & easily replaceable. Instead of putting all that stuff on the inside, I'd attach scenery to the sides & back of the tank- & if you live in a cold climate, you can also "insulate" behind that, to help the heat stay in the tank. Inside I use hides, branches or driftwood, & substrate, but nothing that I can't remove to clean or replace.