How to draw the plane of building steps in detail?

The detailed plan of steps and stairs is a horizontal projection obtained by passing an imaginary horizontal section through the middle of the first staircase (under the rest platform) on each floor and then projecting downward. In essence, it is a local enlarged view of the stairwell in the floor plan of the building, which is usually drawn at the ratio of 1: 50.

If a house has more than three floors, when the position and steps of the stairs are the same as those of the middle floor, usually only three floors are drawn: the bottom floor, the middle floor (the standard floor of the drawing) and the top floor. When the position, steps and steps of each floor are different, the floor plan of each floor and the detailed floor plan of each step of the townhouse should be drawn separately. Draw an indicator line with an arrow at each step and write the words "up" or "down". The plan details of steps and stairs are usually drawn in the same picture, and they are aligned with each other for easy reading, and some repeated dimensions can be omitted.

Axis numbers should be marked on the floor plan of steps and stairs, indicating the position of stairs in the house, and indicating the size between axes and the elevation of floors and platforms. In the stair plane, the number of horizontal projections of the tread surface of each stair part is one less than that of the corresponding tread in the stair part, because the top tread surface of the stair part is flush with the floor in the plane.