Mine is made out of 3/4 inch. It seems to sag as the snakes grow. Each level is 2 32 Qt tubs wide. I had 6 1000 gram females in the bottom three levels. I moved them to another rack. The rack didn't bow as bad but the animals I replaced them with are approaching 700 grams and I can see the levels starting to sag again.
The only problem with installing dividers is how to attach them to each level. Does the weight of the level above hold it into place? Trying to screw or nail each one into place is going to be very tricky.