Windy City Rooftops: New Chicago Building Code Overhauls What’s Overhead

Architects, building owners and developers in Chicago are all going to start looking up this summer — toward the roof, that is.

Some of the most drastic changes in the new building codes the Chicago City Council approved in April of last year involve the design and construction of roofs. As pieces of the new building code come into force this summer, builders, owners and developers will have to carefully evaluate their plans to make sure they are staying within regulations without sacrificing cost and efficiency. 

“We’re in a bit of a gray zone through the spring — companies are free to use the new or the old building code,” said Jason Wilen, a senior associate at Klein & Hoffman, a Chicago-based architectural and structural engineering firm. “But what code gets applied to your building depends on exactly when you applied for a permit and when each part of the code goes into effect.”

Chicago building professionals will need a team on their side to help them prioritize and review their construction plans based on the code updates.

Wilen, who serves as one of Klein & Hoffman’s roofing experts, said some of the changes may take Chicago contractors by surprise, because they represent a 70-year leap in building standards — the city’s building code was last overhauled in 1949. The new code brings Chicago more into line with the latest edition of the International Building Code, transforming a homegrown code into one based on the most commonly adopted model codes used in the U.S.

The overhaul is also made more challenging by the fact that the new code’s 12 volumes each take effect on different dates. While the section governing energy conservation became mandatory in January, the “Building” and “Rehabilitation” portions of the code will not come into force until August. While most of the roofing regulations are contained in the “Building" code section, Wilen said certain code updates are contained within the energy section, meaning that builders cannot just ignore roofing updates until August, and must plan ahead now.

What’s Changing

There are six primary areas of increased stringency for roofs contained within the 2019 code updates, according to Wilen. 

The most important for Chicago builders is wind uplift pressure resistance — how to attach roof systems to keep them from rising up and flying away in high winds. The new wind uplift requirements have been lifted straight from the 2018 International Building Code, Wilen said, which includes “proximity to a body of water” as a significant risk factor. Because of Lake Michigan, Chicago is now subject to some of the most stringent wind uplift requirements outside of hurricane zones.  

“We all know how brutally the winds blow during the winters here,” Wilen said. “The code also becomes more stringent the higher you build. Downtown Chicago is a double whammy, next to Lake Michigan and with some of the tallest buildings in the country.”

Next most important for Chicagoans to consider are metal roof edges and copings that line roofs across Chicago. Here, too, tall buildings and proximity to water mean Chicagoans will face especially stringent requirements. On low-slope roofs, which Wilen said are ubiquitous in Chicago, the accepted designs have now changed, so contractors who have been installing roofs in the same way for decades now have a new rulebook.

The code also has strict new requirements for ballasted roofs, which are often used for their low cost of installation, since they require a membrane to be weighed down with rocks or other weighty materials, rather than fastened in place. While Wilen doesn't anticipate that owners will be required to remove their ballasted roofs, he expects owners may not be able to replace them with the same techniques when it comes time for reroofing.

The other three areas of updates are more stringent requirements for plant-covered “green roofs,” new regulations governing repairs and specific standards for various roofing materials, like single-ply roofing, modified bitumen and ethylene propylene diene monomer rubber.

Who Needs To Worry About It

The updates to the building code will be most important to contractors and other builders in Chicago. The code updates could significantly alter proposed budgets for new projects, Wilen said, so builders should be familiar with the 2019 code before bidding on new work.

Anyone who owns a building in Chicago, especially large landlords and developers with portfolios of buildings, should pay attention to the new roofing codes, Wilen said, as should property management companies and other real estate companies that deal in the built environment.

The good news is that most Chicago building professionals already have the new codes on their radar and are making the appropriate preparations, Wilen said. Some were prepared even before the new code — many of the roof designs that Klein & Hoffman has provided over the last five years would stand up to the new code without any changes.

Wilen said he hopes the code updates will help propel Chicago buildings into the future.

“It was such a major undertaking to overhaul this document,” Wilen said. “With so many stakeholders in the code, it took five years of effort to push it over the finish line. But now, Chicago is getting on board with the rest of the country.”

This feature was produced in collaboration between the Bisnow Branded Content Studio and Klein & Hoffman. Bisnow news staff was not involved in the production of this content.