DISTRICTING RESOLUTION ANNOTATIONS 



259 



street in a one and one-half times district, he can add on an upper 30 feet 

 provided he sets the upper 30 feet back 10 feet from the street line. He 

 can make that setback right from the height limit in the form of a mansard 

 which would slope back in a' ratio of one foot horizontally to three feet 

 vertically, or in a setback of three and one-third feet for each of three 

 stories, or in a setback of 10 feet for the whole height of 30 feet ; then he 

 can set back again above the top of this set-back provided he keeps in the 

 same set-back plane. In general the set-backs might be determined by a line 

 drawn from the centre of the street up through the horizontal line in the 

 street wall on the street line at the level of the height limit on the street 



SETBACK PRINCIPLE!. 



Typical example in a l'/z times district, for streets 50' to 100' wide. 



The setbacK line always 

 runs up from the cen- 

 ter of the street 

 through the limit- 

 ing height at the 

 street line. 



^ Street \f 100' wide & 



Fig. 140. 



line for that district and street. In the street in question this horizontal 

 height limit line would be at a level of 90 feet. These two lines would 

 determine a plane which might be called a setback plane, and no portion 



