We had a PT deck, with steps leading from the lower level
(basement/ground) to the upper deck (1st floor). The steps were 3'
wide, and we had a series of 2, 2x6 on each riser, for a total of 11
risers. We had two stringers for the steps.

We had the PT flooring on our deck replaced with TimberTech. On our
steps, we used 5/4" planks. The 5/4" planks have a 16" spam
requirement, which means we now need to add a 3rd stringer in the
center of our steps. Unfrotunately, the steps were put up before we
realized the spam requirement.

Is it possible to add a 3rd stringer (down the middle) of 2x12 without
taking off the steps?

If yes (or even if no), what is the easiest way to make another
stringer to match the current two?

THANKS in Advance...

-- Jim