I have a rack that is PVCx and I rabbited the shelves in to the sides and screwed them after that was done. Doing it again I'd make the sides, top, and bottom, heavier (1/2 inch) and do the same with the 'box' and screw the back to the sides and use a turning catch to hold the shelves in. It would make cleaning a thousand times easier to be able to pull out a shelf and wash it rather than lay on the floor and reach in to try to clean it. The other thing is I'd look around to see if I could find a shiny sided version the peddled texture makes cleaning a touch harder.