This section is from the book "Practical Real Estate Methods For Broker, Operator & Owner", by Thirty Experts. Also available from Amazon: Practical Real Estate Methods for Broker, Operator, Owner.
Now taking up the first of these items I would call attention to the fact that one of the most difficult problems of condemnation proceedings is that of consequential damage. Consequential damage arises, say, in a plot of ten lots in one ownership, five on each street, when for some purpose eight of these lots have been taken, leaving two lots, one on each street. Manifestly the value of these two lots remaining is not nearly so great in proportion as the value when in a plot, as they are not so susceptible of improvement. The same case, of course, would apply to property that is improved where a part of a building is taken; the remaining part of the building often is not as valuable in proportion as it was before part of it was destroyed.
One of the most interesting cases along this line that I have had confront me was that of several inside lots where a proceeding for widening of an avenue necessitated taking some of the lots, a portion of the inside lots thus becoming a corner. The question then arose as to the measure of damage sustained by reason of taking this property. The owner's experts claimed that he was entitled to the full value of the property taken, while, on. the other hand, I first fixed the value of the property at the time of the commencement of the condemnation proceedings. I had maps drawn showing that while the condemnation proceeding would take part of the inside property, it would leave the owner with a prominent corner, thus obtaining by condemnation what he could not obtain by purchase, as he had been unable to buy the corner plot. In addition, he gained a very wide avenue front for his property, and where the neighborhood had been inactive the improvement greatly enhanced the property for business. In view of this change of situation, I valued the remainder of the property at a great deal more in proportion than I had the original property. I then deducted the value of the remainder of the property from the original value of the entire property, the difference, in my opinion, being the measure of damage sustained by the owner. This theory is supported somewhat by the Charter of the City of New York (Section 822), which provides for this method of fixing damages in acquiring water-front property, and why it should not apply to other properties I cannot see.