I am an architect in a tricky situation. The contractor poured a set of concrete steps too low, so that the top of the landing is 4” lower than the bottom of the door. The steps are a continuous pour, the front steps of an historic church. He is suggesting topping each step with concrete, increasing the thickness incrementally on each higher step. Although this would work out mathematically to give the proper code required heights, I am concerned that the concrete would spall or crack over time.
what is the minimum thickness to “top” new concrete over newly poured but dry concrete?