How to protect stair stringers from water rot?
I had a similar problem with stringers in direct contact with cement that had water runoff. I sawed off 1/2&quot; from the bottom of each of four stringers,screwed in 4- 2 1/2&quot;  stainless steel lag screws into the bottom of each stringer. Once back in place, backed out the lag screws like leveling a washing machine. End result, the stringers were 1/2&quot; above the concrete and the water just drained by. I guess it's kind of a hack but it worked great. Twenty stringers is a lot of lag screws though.