In M1-4 Districts, the underlying height and setback regulations shall apply except as modified in Section 115-231 (Permitted obstructions).

In C4 and C6 Districts, the underlying height and setback regulations are modified as set forth in Sections 115-231 through 115-235, inclusive.

For zoning lots subject to the sidewalk widening requirements of Section 115-31, the boundary of the sidewalk widening furthest from the street line shall be considered the street line for the purposes of applying all height and setback regulations.

All heights shall be measured from the base plane.