furniturejointswoodworking
I'm specifically referring to the design seen here.
It's quite hard to view how the corners are joined together. I found a couple of other designs that are similar, it kind of looks like a butt joint and then some lag bolts to hold the horizontal boards but I cant be sure, any ideas?
A nice ladder can be built similar to the following. Use 1x4 sized material and bore holes through it to accept closet pole for rungs. Select the angle of the vertical rails to suit your space and desired usage preferences. Rung spacing should be even - but not too close together.
Ladder can be simply screwed through the side rail of the bed into the edge of the vertical ladder rail.
Since you are doing sturdy x-bracing under the bed itself, and two adjacent sides are cross braced as well, you have three braced frames in three planes, and none of the frames are overly long and skinny, there is adequate bracing for the entire structure. If you can in any way anchor the structure to the walls as well for additional rigidity, you will be better off.
Even if you can't, as long as the frames are truly rigid and do not rack in the least, you will be fine. The one unbraced post is a bit of a problem unless anchored at the base because it can move if bumped against. If bumped hard enough, you could lose the vertical support at that corner. Thus the connection of this post must be as rigid as possible at the top connection to the bed frame. It's essentially like a table leg, a loose one is nearly useless.
Best Answer
The joints in the design you referenced are actually plain lap joints held together by lag bolts or lag screws. If you wanted to get a bit fancier, you could always use half-lap joints or one of the other variations shown below. These will require a bit more work, but all but the dovetail lap shown below can still be done with just a circular saw and a chisel. The advantage of a half-lap joint is that the lags are no longer holding the weight of the assembly in shear. The wood of the column under the joint is supporting it in compression, while the bolts only hold it together.
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Either way, lap or half-lap joints are a plenty strong design, although the former lacks a little bit in aesthetics. If you're okay with the look, that will probably be the easiest method of construction, especially if you plan on disassembling it at some point (which you'll have to do if you ever plan on moving it out of the room!).
A butt joint would be if the two boards formed a T. These are used for the legs/vertical columns in the design you reference. For these, I'd use wood glue and wood screws to hold them together.
Wood glue will help strengthen all permanent joints. So I'd recommend gluing all subassemblies that won't need to be disassembled for transport. This will also help reduce confusion when reassembling later.
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