CTBUH Research Paper ctbuh.org/papers Title: Was the Home Insurance Building The “First Skyscraper”? Authors: Mir M. Ali, Professor Emeritus, University of Illinois at Urbana-Champaign Gerald Larson, Professor Emeritus of Architecture, University of Cincinnati Subjects: Architectural/Design History, Theory & Criticism Keywords: Construction Historic Context Structure Publication Date: 2019 Original Publication: CTBUH Journal 2019 Issue IV Paper Type: 1. Book chapter/Part chapter 2. Journal paper 3. Conference proceeding 4. Unpublished conference paper 5. Magazine article 6. Unpublished © Council on Tall Buildings and Urban Habitat / Mir M. Ali; Gerald Larson Debating Tall Was the Home Insurance Building The “First Skyscraper”? Chicago’s Home Insurance Building, the 12-story office building designed by William Le Baron Jenney, completed in 1885 and demolished in 1931, has frequently been referred to as the “first skyscraper.” However, it is not a settled academic matter. The following is a concise distillation of the central arguments behind an upcoming set of papers in a special proceedings book, and a key discussion in the first session of the “First Skyscrapers | Skyscraper Firsts” Symposium, being held on the fourth day of the 2019 CTBUH 10th World Congress. YES turning the exterior into a “curtain wall” article that identified three skyscrapers Mir M. Ali system, heralding the use of well- that were taller, and which were Professor Emeritus, School of Architecture, developed curtain wall construction in completed before his commission. University of Illinois at Urbana-Champaign future skyscrapers. This building’s pioneering structural system led to what However, if we accept the definition The Home Insurance Building in Chicago is known as the “Chicago Skeleton.” requiring the use of iron skeleton framing, qualifies as the first skyscraper, due to the Home Insurance Building still does not being an innovative structure When the building was completed at the qualify as a skyscraper, because, while its emphasizing lightness, ample daylighting corner of LaSalle and Adams Streets, for interior structure consisted of iron and curtain walls. In traditional the first time, a metal skeleton, instead of skeleton framing, its exterior structural construction, masonry walls carrying the masonry, formed the primary supporting system was a polyglot of masonry bearing weight from upper floors needed to be structural system for a commercial walls and iron-reinforced masonry piers thick and heavy, and reached a practical building. It stood out from other buildings and lintels. Its two party walls, and even height limit because of their low carrying of that era as the first skyscraper, because the first two stories of the street capacity. These walls didn’t allow large it possessed all the fundamental features elevations, were also load-bearing window openings in the exterior, thereby of a skyscraper. masonry. Only the piers in floors 3-10 of blocking abundant natural light. With the street elevations contained iron masonry exterior walls and without the sections, while the spandrels in these skeletal construction, it was practically NO stories consisted of masonry walls sitting impossible for any building to evolve to a Gerald Larson on shallow, segmental iron pans. Further skyscraper of great height, even though Professor Emeritus of Architecture, evidence, stemming from Jenney’s own elevators could reach such heights. University of Cincinnati details, reveals that he had no intention of Skeletal construction singularly paved the creating a “skeleton frame” in the two way for future skyscraper construction. Winston Weisman’s 1953 proposition was street fronts. that the Equitable Building in New York of For the Home Insurance Building, 1867 was the first skyscraper. This was originally built in 1885 with 10 stories, and because it was the first building designed to which two stories were added in 1890, to exploit the elevator by making its floor William Le Baron Jenney created an heights taller than convention, because iron-framed, lighter structure for much of stairs were no longer needed. This resulted the building, carrying the building’s loads. in a building that towered above its In his design, cast-iron box lintels/beams neighbors, due to this extra height. If one Mir Ali & Gerald Larson above the wide window openings, cannot accept a seven-story skyscraper as will appear in First Skyscrapers, Part I, precursor of the latter-day “Chicago a “first”, but arbitrarily requires a minimum at the “First Skyscrapers | Skyscraper Firsts” Symposium on Thursday, Window,” framing into columns that were of 10 floors, there were many such 31 October. encased in small masonry piers for buildings constructed in New York and fireproofing and protection against the Chicago prior to Jenney’s commission to climate, rendered the exterior walls design the Home Insurance Building in non-load bearing. These perimeter lintels/ 1884. In Chicago, this type of building was beams carried each story floor by floor, referred to as a “skyscraper” in an 1884 .