John Hancock Tower (1976)

One of Boston's most notable modern skyscrapers

The CEO of the John Hancock Mutual Insurance Company, Robert Slater, was an aggressive man, who had great expectations for his company. To express the success of the company, he wanted to construct a large headquarters after their rival, the Prudential Insurance Company, built the Prudential Tower in the 60’s. I.M. Pei & Partners was commissioned for the design after getting recommended by Boston Redevelopment Authority’s Edward Logue. The location of the site was to be just off of Copley Square.

Originally in 1966, the first design proposal was for the tower to be a masonry cylinder that was sliced to create a courtyard on Clarendon Street, which was one of three proposed buildings. After the Hancock company underwent internal changes, the design process was delayed for an entire year. When the company came back they brought along new requirements for the proposed headquarters. The new proposal was to be 2 million sqft in one building, compared to the 1.5 million sqft of the previous proposal.

Pei considered dropping this project all together due to the amount of projects the firm was working on. Instead, he decided to hand the project over to his partner, Henry Cobb. Cobb was selected because he previously designed the largest building Pei’s firm worked on before and was a native Bostonian. Cobb accepted this challenge and Pei know that it was in good hands because of Cobb’s deep appreciation for the city of Boston.

Cobb started from scratch, on September 15th, 1967. Realizing that Copley Square was and important public space that included many significant buildings such as Trinity Church, Copley Plaza Hotel, and the Boston Public Library. To respect the surrounding area, Cobb wanted to create a tower that seemed to have the least presence on Copley Square. The design was to be a 790’ high tower with 60 floors. The slim face of the rhomboid shape directed toward Copley Square. To make the face appear more slender, Cobb subtracted triangular notches that ran from the bottom to the top of the façade. The material choice for the facades was to be a reflective double layered mirror glass skin. The reasoning behind this choice was to allow the tower to reflect the surrounding buildings and to have the tower seem as if it just disappears into the sky.

Construction began in 1968, with many issues soon following. The first problem that arose was with the digging of the foundation, this affected the surrounding buildings. It damaged the other foundations and in the case of the older buildings some of the wood pilings they were sitting on shifted. Trinity Church was one of these buildings that was damaged. The next and most notorious failure that occurred was with the glass façade. Starting in 1971, sporadic breakage occurred in the windows, some cases were explained and others weren’t. Then in 1973, when a wind storm with 75 mph gusts hit Boston many sheets of glass fell from the facades. To temporarily fix this problem the openings were replaced with painted black plywood sheets. The tower received the nickname of the “Plywood Palace”, due to 1/3 of the façade being plywood sheets. Cobb decided that the whole building was to be re-glazed with a higher rated glass. 85% of the glass was replaced by May of 1975. The other concern of the building was the building’s excessive sway. To support the structure, they braced the inner core.

The tower finally opened in 1976, 4 years behind schedule, $160 million including legal fees, which was twice as much as the estimated cost. The project encountered many criticisms along the way, but as soon as cover photos for magazines and postcards were being taken people began to recognize the John Hancock Tower to be a great modern skyscraper and an iconic building for the city of Boston.



200 Clarendon Street, Boston, MA