I installed a new subfloor sheathing in my second floor half bath. The edges are between 1/4 and 1/2 inch from the wall. In a few spots, the wall edges are not totally smooth do to poor removal of previous rotted subfloor and uneven blocking (jagged edge that was not cut or sanded smooth). Basically there are potentially access points for liquid materials to enter the void (don't know the technical term here, aka "the subfloor abyss")
What can I do to seal off this gap so I can pour some self leveling compound? Mildew resistant caulking? Wood filler? Mesh tape + some kind of compound?
Backerboard or DITRA for a floor tile substrate?