All photos taken post-completion |
My current room is a bit smaller than the freshman double I had last year, so when I moved my glass desk here, I had trouble fitting a bed in the space. The conventional loft-bed setup calls for posts at each corner, but this setup would either conflict with a desk or have a post right in front of the door. Not ideal.
I had a few ideas for what I wanted in a loft:
- 6'+ height: I didn't want to hit my head on it, nor did I want my tall-ish friends to hit their heads on it either.
- minimal diagonal bracing: I wanted my loft out of the way and not be the only thing people see when they walk in my room. Diagonal bracing takes too much space from an aesthetic point of view.
- open space: there will be no posts blocking my desk or the center of my room. All posts will be as close to the walls as possible.
- stability: I should be able to hang from all points of my loft. I should be able to climb on and off my loft without creaking or other sad noises.
East Campus rush provided all the lumber I needed (we use up a lot of wood) and even several 3/4" bolts, which proved useful (though overkill) in assembly. I made the bedbox using 2x8s and 2x4 slats; posts are 8' 4x4s; I had one long 2x6 crossbeam and some 2x4 braces.
Tools used: chopsaw, circ saw, drill w/ 3/4" auger bit.
Tools used: chopsaw, circ saw, drill w/ 3/4" auger bit.
Drawings from CAD: my working drawings are much more chicken-scratch |
CAD model of the planned loft |
The bedbox was the first thing I built. Outside, I cut and dry-fitted all beams and slats, leaving room for posts, then drilled pilot holes for each screw to prevent splitting. Slats were spaced 12" apart. I then clamped 4x4 posts in place to drill bolt holes through both the bedbox beams and posts. This ensured that the bolt holes would line up. I stuck bolts through the posts and leaned them against the wall. Then friends helped lift the bedbox to 6'-1/4" as I secured the bolts.
I chose 6'-1/4" to be the height of the loft because I have a 6' tall bookcase. I gave myself a 1/4" error to ensure that the loft would rest on its legs and not the bookcase (1. dorms get upset when their institutional furniture gets locked in wooden structures, and 2. I have no idea how structural that bookcase is over time.)
1/2" plywood added after loft was completed. Here you can also see the 2x4 screwed into 2x8 for slats to rest on. |
Once the loft was secure, it was a simple matter to climb up and screw in bracing. I did grudgingly add one diagonal brace, but it's not evident from the ground.
Crossbrace added |
Sideview: One horizontal support further attaches the corner to the post. |
A bookshelf nook underneath stores my mess! (There's a few outlets that prevent shelves from sitting flush against the wall) |
Though fun, using the bookcases and slats to climb on my loft wasn't going to be feasible with a mattress, so I quickly attached a ladder to a post. The 2x4 leg of the ladder is slightly offset from the edge of the bookcase so I still have grip room.
The one diagonal brace. I also wedged a piece of wood between the crosspiece and the wall to prevent lateral movement. |
I'm really happy with the results. There are no ominous creaking noises when climbing/moving around my loft, and I don't notice it when I'm working at my desk. I've even hung from the middle of the crossbeam without seeing noticeable deflection. Running up and swinging from it, though, does produce sad creaking noises (not sure what my friend was thinking there)
This cantilevered loft design is the first of its kind in East Campus, so I was a little worried about how well it would hold up with use. In particular, I wanted to know how much force I could put on the cantilevered end before strain would break it or before it fell over (there's glass under that!) If it did well, maybe I could hang a swing from it in the future.
Well, I have a CAD model in Solidworks. Might as well put weight on it in FEA and look at the pretty colors, right?
In Solidworks, I assumed my dimensional lumber to be red pine and Douglas fir and my bolts/screws to be generic steel alloy. (There a few varieties of pine common to Massachusetts, so I just picked one that had material info available.) I then put 300lbs of force on the farthest slat (right next to the diagonal brace) and ran the simulation for static displacement and strain. Below are the results.
The loft moves about the pivot leg |
Crosspiece and pivoting post experience the most strain, as expected |
Close up picture of strain around bolts |
So, the simulation is pretty close. Let's try 500 lbs.
What happens when you put a literal ton of force on your loft? Solidworks complains and refuses to finish static analysis. (it outputs the message "Large Displacements Detected" before failing, so I assume the loft falls over.) The following is its output of "33% load", so with 667lbs.
I see posts lifting off the ground |
That's a bright blue. |
(no, I don't have a physical ton to test this out empirically)