So I got a domino. And I'm makin a bunk bed.

[Birdhunter]

I'd worry about the frame racking.

 

[Gary in Texas]

I'd worry about the frame racking.

Which is why I suggested the 2x8's on the end, and not 2x4's at the end on the side, as well as adding two cross braces at each end, or.....two cross braces at the foot end and some custom headboards at the other......

 

[MahalaHomecraft]

I will definitely add the cross braces.  As far as the stairs go, the customer wants stairs, so she's getting stairs.  Ceiling height here is only 92 5/8".  She's also being kind of a pain about not having the bottom bunk "right on the floor."  My plan was to build the two trays and the verticals, bring everything to the job site for assembly, and settle on exact heights during that process.  The stairs etc will come after and be based around the first part.  Because of the look the customer wants, all of the framing material has to be s4s, and everything is going to be poplar with the exception of framing under the stair case, which will be doug fir.  I will have to see about upgrading to 2x6 for the tray surrounds.  There is 1x6 on edge which will also be joined with the domino to the 2x4 in the current design.  This woukd add some structural integrity, but now that I think aboit it I can just replace both the 1x6 and 2x4 with 2x10, and then I know I have nothing to worry about.  Do you think 2x4 on 24" centers will be enough for my joists if I'm using 2x10 for what would essentially be rim joists?  I've been picking up my sketchup game lately, so I'm just gonna redraw the project with some of these changes in mind.

 

[Tinker]

I think I would use barrel bolts to anchor the rails to the ends.  With poplar, I am thinking full 8/4 for all structural surrounding frames whether 2x6, 2x8 or whatever. especially if boys are going to be the "sleepers"  :
Tinker