Most unit prices consist of averaged prices across a class of project.
A typical example would a multi-family project.
A multi-family residential building from 3–5 stories will not change much per square foot either at 3 stories or 5 as far as estimates go. At 6 stories you will see a price jump as structural and fire requirements change at this point. The price will stay consistent until you breach 10 stories. This time it’s due to the change in equipment needed. 11 to 30 stories will again stay fairly consistent. At 31 stories you are dealing with a logistics nightmare. The deployment area is tiny and everything going in and out of this building needs to be timed so that the surrounding trees and buildings are not overwhelmed by your construction activities.
It should be noted that most projects over 15 stories require a precise estimate involving the final contractor as seemingly minor changes and variations can spiral costs out of range.
MKDesign 