The carpenter said there was nothing he could do without tearing out the ceiling under the stairs and rebuilding the staircase. The designer was in a dither because of the time and expense that would entail, so I said, “OK Jon and I will fix it.”
Here’s what we did. I went to the lumberyard and bought framing braces, 2-inch angle braces, 1 ½ inch dry wall screws, and a big eyehook.
We tied the stair nose to the upper hall with the framing braces, not pretty granted but only three inches of painted wood to be showing on the stairs and where it came over the nose. (Photo 1)
OK, now for the risers; some were worse than others. The top riser was pushed back almost an inch! We drilled a pilot hole in each riser and screwed in the eyehook. (Photo 2) and threaded a heavy rope though the eyehook. (Photo 2a)
Next we tied the rope around a stretcher pole and using the previous stair as a lever point, Jon pulled the riser back into place while I fastened the riser and tread together with the 2-inch angle brackets and dry wall screws. (Photo 3) Notice that I had the young strong guy doing the heavy lifting.
The end result -- the stairs were reinforced at a small expense to the homeowner compared to what the carpenter wanted to do and charge. (Photo 4)
The stairs were secured, the painter caulked what cracks that remained, we installed the carpet, job was beautiful, and the customer and designer were thrilled. Life is good.