I'm building a lofted structure that includes a queen bed, storage stairs, and some storage space over my door. Here is a rudimentary mock-up I made in PS.
All the vertical support beams are 4x4s and the outside frame of the bed will be 2x6s. Like this: I will be replacing the wooden grooved pieces with metal L beams and adding a support rail down the middle of the frame. Also I'd turn the 2x4s onto the broadside.
The brown colored pieces in the mockup are for support. Using this design what would be the best way to secure the joints from shear force (add metal brackets, mortise and tendon the joints etc..)? I want this thing to be solid.