Step 4: Fleshing out the Steps
After the linkage was assembled and tested, it was time to build the stairs themselves. Some additional 1x2 framing was added to support the steps, but it was kept very minimal.
Some quick calculations were made to figure out the number of steps and sizing. To force the perspective, the steps would get more short and narrow toward the top. In my case I varied the width from 30" at the bottom, down to 18" inches at the top, and from 9" high to 5" - so that's a pretty dramatic difference.
Rigid foam insulation (extruded polystyrene) was used to build out the stairs. First, two long stringers were attached to define the outside taper. Then, working from the bottom up, stair pieces were cut and assembled with liquid nails. After all the stairs were together, masking tape was used over most of the seams to clean up the appearance before painting. The end result is a six foot staircase you can easily lift with one hand!