I am planning on getting "wood crates" to be the legs of a lofted bed.
Each box measures 18" x 12". For thickness, the long sides are strips of 1/4" pine and the short sides are solid 3/4" pine:
I want to make the legs 54" (18*3) tall in front, and stacking four crates with some 2x4s at the top (to fill in the gap to reach 54".
Starting in the bottom left corner and going clockwise: I plan on cutting out slots for two 2x4s in the crates for stability. Then, along the back left, there is a 1' 2×4 for support (and will probably add another one in the middle). Along the back bottom is a 1×2. Inside the front bottom is a 2' 1×2. Last, the top frame is made of 2x4s.
Will this design be strong enough to support a sheet of plywood under a mattress? Is there a good rule of thumb related to figure this out?
Edit
The wood crates are pine and they are all the same dimensions. They are fastened together with staples as seen in the picture. (These are commonly available at home improvement stores.) My qualm is how these are marketed as decorative boxes.
Best Answer
That's impossible to say because not all such boxes are built to the same specifications. Wood species and size, fastener type and schedule, and other factors vary widely. If forced to answer it would be no out of an abundance of concern for safety.
I would follow your plan, but lay 1x4 posts alongside the boxes where appropriate and aesthetically pleasing. Fasten the boxes to the posts and to the bed frame. Make sure it all has enough diagonal bracing, which is the most likely failure concern. That gets into design a fair bit, which isn't really on topic here.