There has been a lot of interest, maybe excitement, read the Comments Section, regarding this 2×4 Ladder. Some in favor and some to the contrary.
I had 2 objectives, 1) Proof of concept. Could it be possible to make a simple, lightweight, mobile ladder to access a 2nd floor? 2) Use 1 board; in this case a 2×4.
The design is based upon a tactical ladder. There are many different types of tactical ladders. The design I chose was a single leg (pole) ladder with alternating steps. There were many conditions needed to be satisfied which led to the final build. This ladder was not built on a whim.
Safety was the biggest concern expressed. I will address some of those concerns by looking at the environment where this was to be used. The 2nd floor is only 6 feet 8.5 inches or 2 meters high. There are Webs 23″ or 58.42cm apart. In the gif, you can see that I am grabbing hold of those Webs to support myself going up, from the 3rd steps, and using them down until I reach the 3rd step. The distance between the Webs is close enough that if the 2×4 Ladder were to slide, it would stop when it hit the floor joist or Web, but is a moot point because I will be holding onto the Webs.
I had to adjust my stance to center my weight to the vertical center of the ladder. Like walking on a balance beam.
I will not be carrying anything up or down this ladder. The 2nd floor being 6′ 8.5″ (2 m) from the ground, I can stand on my toes to place, throw or slide anything up there. As for down, I can stand on a milk crate to reach the edge and pull it off or toss it off.
In the first design, I did not use the cutouts. After reevaluating they were attached to make the step deeper.
I considered placing a notch where the ladder came in contact with the wall. A good idea, maybe will add later. I also considered adding a bracket where the ladder came in contact with the wall. Another good idea, maybe will add later. For this model I decided against those options. This is a proof of concept.
The facts of the 2×4 Ladder is that the design and build confront conventional wisdom. Because it is different some question the physics of its existence. I could liken this questioning to putting wheels on shoes. At first it had mixed acceptance. Certainly, this 2×4 Ladder is not OSHA approved.
This 2×4 Ladder works, it is within acceptable tolerances for the existing conditions. You can accept and build it or design something else.