Custom Cage Durability

Hello folks, I'm looking to make my Beardie a 4x2x2 viv out of plywoodm and I was wondering, how study are enclosures like these? I'm hoping to use the enclosure as a way to consolidate space by putting my 10 gallon aquarium and corn snakes 10 gallon tank on top. Would a normal plywood viv be able to handle this? (keep in mind the full aquarium is over 100 pounds while the empty on is about 10 pounds) Would I be better off making a brace out of 2x2s or 2x4s and then covering it with the plywood? Thank you!

Mine is really sturdy. I'm not sure about a full fish tank (I tend to over design things involving water) but I have a 20g snake cage on top of mine with probably 20-50lb of dirt in it and no problems. I am able to sit/stand on it fine.

It's been a minute since I've done that sort of math but this widget seems like it might be helpful. http://www.woodbin.com/calcs/sagulator.htm
Could always design braces for the ceiling if you aren't confident - like foors in houses have.

Another thought. Depending on how you do your lighting it may help or hurt your other two enclosures. The solid top warms up pretty well and can warm up the cages on top of it - I have a RHP in it now for my cornsnake and need a foam insulation barrier to keep my hognose enclosure on top from over heating. When it was just a light bulb it was a nice gentle heat.

Thank you for that calculator! It looks like a tank would be too heavy for a regular shelf, so I'll probably add a couple braces just to be safe. He has a basking like that heats up to 100, so I might need to put some insulation over whichever tank goes over the basking area. What thickness foam do you use? Would foam be melted by an under tank heater that gets up to about 87? (i'm thinking no as 87 isn't terribly hot....)

I think I've got 1" foam as it was what I had on hand. but it wasnt needed when it was just a light bulb. The melting point of polystyrene is reall high, shouldn't be a problem.