Thank you for the quick comments. I'll try to clarify. The treads have a rounded nose that projects about an inch (they look like typical interior stairs). However the treads do not notch into the stringers on the sides, they are supported from below. Therfore, there is a small gap on the sides of each tread where it "almost" abuts against the wall. This gap runs all the way down the stairs: along the edge of the top tread, around the nose of that tread, down the riser to the next tread and so on. Putting the quarter round along the edge of the tread and vertically down the riser is no problem but how do I "bend" the quarter round around the nose of the treads. Is there any other material (maybe a flexible quarter round) that could be bent around the nose on each edge of the treads. I could just try to caulk or fill the gap all the way down along each side of the stairs but I was afraid that this would crack over time. Thanks again.