What’s the best way to finish this trim

baseboardfinishingtrim

So I'm doing my baseboards in my basement, and I'm running up to what was previously installed. I'm going to slide the baseboard all the way flush with the vertical part. From there, I'm a little stumped what to do. My thoughts were to:

  1. Cut the cap the goes along the stairs vertically flush with the end of the stairs and then leave it blank from the base straight up
  2. Find another piece of trim that matches the cap along the stairs and run it vertically down to the base. The problem is, that cap is thicker than the base, which I could taper down to meet up, but I have no idea how I'd deal with the cap on the top of the base
  3. ???

Any thoughts as to the best way to blend these?
enter image description here

Best Answer

Abutting moldings are often resolved with transition blocks. You could make a rectangular piece, slightly wider than the current gap. Trim back the angled cap so that it is flush with the vertical line at the end of the stairs. Trim back the base molding a bit. Make the block a bit taller than the end of the cap.

The ideal thickness would be different from all that abut it. Reveals (intentional offsets in thickness) are easier than trying to get exact flush matches. And they are usually better looking.