Installing the new pieces...
Started with the 5/8" plywood, coated with kilz. I had to make small filler pieces for the ends due to not taking the door out. If i did take the door out, then i could have used solid pieces. Also, I lost 2 screw holes, but i don't think that will be an issue.
Next is the new step structure. Put together with pressure treated 2x4 and screws.
Some difficulty on keeping these pieces together. There is little access to get screws in from the outside to keep everything tight. I did manage to get a couple screws in to help.
Here is an example of how bad it was sagging with the rotting wood...
I reused the outboard most bolt holes, and used 2 unused holes. 3/8ths bolts and lockwashers. Yes, I did drill through the doorjam...
A new plywood deck piece, same 5/8"... It made no difference in the dimensions previously used.
And some new tile! Actually, its just adhesive backed vinyl tile. Easy as butter to cut and install, and its cheap. $.79 a tile. You may notice some un-even cuts here. It turns out that the dimensions inside the hole are as crooked as a congressman. off by 1/2" front to back, and 9/16" side to side. Freehand is your friend here.
Done! It took awhile, but it looks much better. So far, its holding up to the weight at the lowest stair, which produces the most torque on the box. The stair unit itself is worn pretty bad, which is also causing some sag of its own, but there's not much i can do about it. I filled in the tile cracks with caulk.
And yea, the bolts are much longer than need be.