This weekend architects, engineers, and other building buffs from around the region will gather at the School of the Art Institute's new Leroy Neiman Center to examine the past and future of a true Chicago architectural staple -- the skyscraper. With "Skyscraper History: Looking Back While Looking Up" as this year's theme for their annual symposium, The Association for Preservation Technology's Western Great Lakes Chapter (or APTWGLC if you really want a mouthful) will tackle topics from local advances in skyscraper preservation technology to the age old question – which city can really lay claim to the title "Birthplace of the Skyscraper"? (Our vote should be pretty obvious?) We caught up with APTWGLC's president Rachel Will, and one of the symposium's presenters, Thomas Leslie, an architecture professor at Iowa State University and author of Chicago Skyscrapers, 1871-1934, just published by University of Illinois Press, to find out what we can expect from Saturday's event.
Curbed: How and why did the APTWGLC choose skyscrapers as the subject of this year's symposium?
Rachel Will: Each year the symposium has focused on a different theme that relates to preservation. Past symposiums have included presentations on historic materials, as well as the integration of preservation of sustainability. This year we decided to partner with the Construction History Society of America. We focused on the symposium on the skyscraper, because being an organization that is primarily composed of architects, engineers, contractors and academics this was topic that sparked a great deal of interest with many of the groups?not to mention being located in Chicago we have great skyscraper building stock as inspiration.
The multifaceted symposium includes the debate focusing on which city can claim to be the birthplace of the skyscraper, but also presentations reviewing the history and evolution of the skyscraper and some of the preservation challenges and successes that are unique to this building typology, there will also be segment that focuses on what is being done today in the world of skyscraper construction.
Curbed: What kind of preservation work is going on currently on Chicago skyscrapers?
Rachel Will: Most of the work on Chicago skyscrapers that is of interest to APTWGLC is often related to the preservation of the exterior facades. A few notable recent preservation projects include:
·Randolph Tower Apartments: The entire building interior was gutted and rehabbed into apartments and the exterior terra cotta facades received a full-scale restoration.
·Chicago Athletic Association Building and Annex: Repair work is just beginning which will include exterior facade repairs and a total interior renovation.
·Lumber Exchange Building (11 South LaSalle): This project included exterior facade repairs of the brick and terra cotta façade of the base building and tower that commenced in 2006. The remainder of the repairs are scheduled to be completed in 2013/2014.
·School of the Art Institute (112 South Michigan) Façade repairs to the precast clad addition (patching and coating of the precast concrete panels), repairs to the limestone cladding and cast iron window frames.
The majority of the preservation work for Chicago skyscrapers includes maintenance type of repairs to the exterior facades rather than large scale restorations. Some recent examples ongoing maintenance repair programs include 120 South LaSalle Street Building, Railway Exchange (Santa Fe/Motorola Building), Inland Steel Building, Chase Tower, Aon Building, and many others.
Curbed: The main event at Saturday's symposium is the debate over which city can claim the title "Home of the Skyscraper" – what's the argument for Chicago? We've got this in the bag, right?
Thomas Leslie: New York may have built taller buildings, but Chicago built better ones—or at least ones that better foreshadowed the way we build skyscrapers today. While William Le Baron Jenney's Home Insurance Building (1884) is still claimed by many as the "first" skyscraper, it was a fairly traditional masonry structure. A later generation of Chicago buildings, though, made technical improvements that were critical to developing the 20th century skyscraper, and it's these that, I think, make Chicago's case.
Tall buildings here had to be innovative in a couple of ways. Chicago's developers were more speculative than New York's, and their profit margins were tighter. This encouraged more rigorous planning and more experimental engineering. But it also pressured the city to allow skyscrapers that were lighter, more skeletal, and—for a time—taller. Foundations in Chicago were also more difficult than in New York. The waterlogged clay under the Loop is notoriously weak, and Chicago engineers had to isolate individual column loads and float them on large lily-pad-like foundations. This encouraged more skeletal frames and lighter construction, both of which are hallmarks of modern skyscraper engineering.
Things changed around 1895. Caissons, or large underground columns, allowed skyscrapers to rest on deep bedrock, eliminating one important difference between the two cities. And the brick industry in Chicago used its political power to change the city's building code, which began to favor masonry over lighter terra cotta. Perhaps most importantly, the 1893 code included the strictest height limit in Chicago yet at 130 feet. While this was eventually eased, it let New York surge ahead in the race for height.
All of this meant that Chicago's most progressive construction occurred the early to mid-1890s. In Saturday's debate I'll make the argument that there's a particular Chicago building from that era that was a revolutionary structure not for its height, but instead for its combination of lightweight structure and skin. It was the first to use virtually no masonry at all; Inland Architect called it the first "building without walls," which to my mind makes it the first recognizably modern skyscraper.
The Chicago/New York argument goes on even today now that One World Trade has been topped out. Chicago wins that one, too, by the way—hands down—but that's a discussion that will wait for the post-debate social hour on Saturday.
·Skyscraper History: Looking Back While Looking Up [ATPWGLC]
The symposium will run Saturday from 1 p.m. to 7 p.m.