Case Studies

Compliant Rooftop Deck in Chicago: Fortress® Framing Case Study Case Study

A Rooftop Deck on Top of Chicago’s Updated Building Code

Fortress® Framing Case Study

Project Details

Chicago resident Marie Delgavio owns an industrial-style loft in the heart of the city’s West Loop neighborhood. What sets her residence apart from others on the block is its private rooftop, which is a “highly sought-after home amenity for city dwellers like me,” Delgavio said.

While incredible even in its bare form, Delgavio saw her rooftop as an opportunity to design a functional and inviting outdoor living space where she could relax, entertain, cook and tend to her container garden. “Living space is limited in condominiums and homes in the city, so it’s important to take advantage of any usable outdoor space,” she added.

A closer look at Chicago’s Building Code Modernization Ordinance

To bring her sky-high vision to life, Delgavio commissioned a new 1,000-square-foot rooftop deck. From the get-go, Delgavio knew that Chicago’s Building Code Modernization Ordinance, which the city passed in 2019, would dictate the deck design and construction process. The landmark ordinance marked the adoption of the 2018 International Building Code (IBC) and International Existing Building Code (IEBC), aligning Chicago’s construction requirements with up-to-date model codes and standards used in other major U.S. cities. The first comprehensive change to the city’s building code in 70 years, the updates provide a critical framework to keep buildings as safe as possible while encouraging innovative design and construction practices.

Prioritizing fire-resistive building materials and methods

The modernization of Chicago’s construction codes focused on several significant areas, including fire and life safety, building materials and the rehabilitation of existing buildings. Most pertinent to Delgavio’s rooftop deck renovation were the code revisions requiring fire-resistive building materials and methods. According to Chapter 15-8, Section 510 of Chicago Building Code, all roof structures hereafter placed above the roof of any building exceeding 55 feet in height shall be constructed of noncombustible materials and shall be supported by construction of noncombustible materials, except the walking surface of a rooftop deck may be of combustible materials meeting the requirements for Class A roof coverings if constructed above a roof of noncombustible material and supported by construction of noncombustible material.” The requirements outlined in this portion of the city’s building code are challenging to meet, but they also put opportunity with the building industry to adopt sustainable building materials and forward-thinking construction practices.

Before the city council passed Chicago’s Building Code Modernization Ordinance, Delgavio may have gotten away with building a traditional wood frame deck on her roof. But an old-school wood frame deck holds a huge combustion risk. History has shown us repeatedly that lumber is not a safe choice in a dense urban environment, where a fire can spread to nearby structures quickly.

Steel framing is the code-compliant, lasting alternative to lumber

Needing a code-compliant, lasting alternative to lumber, Delgavio turned to Evolution steel deck framing from Fortress Building Products. A fire-smart system, Fortress® Evolution received a Class A fire rating through Intertek, an independent assurance, inspection, product testing and certification company. A marker that indicates superior fire performance, a Class A designation is the best fire rating a building material or product can receive. Materials that fall into the Class A category are very unlikely to contribute fuel to a fire, reducing the vulnerability of a structure and the people inside of it or near it.

Examining steel’s high-performance, low-maintenance qualities

A noncombustible option that meets 15-8-510 of Chicago Building Code, Evolution provides premium weatherability and low maintenance qualities. Leveraging the proven performance of steel, the framing system can sidestep common issues that plague wood frame decks, such as deterioration after long-term exposure to moisture and warping as a result of extreme changes in temperature. In application, the steel frame profiles will remain straight and true over time. This makes for an enduring, dimensionally stable deck framing solution that keeps the surface material flat and smooth underfoot. In this instance, the project team installed a ¼” underlayment material on top of the frame and then put down contemporary stone pavers.

Strong, stable and resistant to the damaging effects of weathering, Evolution’s steel profiles are also engineered to handle the weight of today’s most in-demand outdoor amenities. Relying on the strength of her steel frame deck, Delgavio elected to install an outdoor cooking area, complete with a grill and a sink to wash off fresh herbs picked from her planter boxes. Further preserving the structural integrity of the steel frame, a powder-coated finish provides enhanced corrosion resistance and UV protection. This enhanced durability means that the rooftop deck will retain its strength and beauty even after long-term exposure to Chicago’s notoriously harsh winters and direct sunlight in the summer.

Compatible steel stairs ensure a safe, complete rooftop deck

The project team took additional steps to ensure a safe, complete deck by incorporating the Evolution steel stair system into the rooftop project. This compatible system sidelines common safety concerns, like poor stringer-to-deck connections and inconsistent rises and runs. These challenges are rampant in traditional wood decks, as conventional stair construction requires cutting pieces of lumber by hand. On the other hand, engineered stair systems have fixed and adjustable stair brackets that can accommodate various rise and run options. Stringer and stair trays already include blocking every 10 inches on center for railing post attachment and stair tread attachment, and self-drilling screws ensure maximum strength and security at connections. This level of innovation ensures that Delgavio’s dreamy rooftop deck remains structurally sound from the ground (or roof) up.

Sleek steel profiles provide creative solution for custom pergola

Not only do steel profiles offer strength and longevity, but they’re also sleek and good-looking. The project team capitalized on these qualities, using Evolution’s noncombustible steel profiles to design a custom rooftop pergola. The modern contemporary steel pergola provides definition to Delgavio’s rooftop deck, transforming the space into an open-air living “room” tucked underneath the towering Chicago skyline. Like its deck framing counterpart, the steel pergola will sidestep any issues associated with moisture absorption, one of the most common reasons a standard wood pergola will deteriorate over time. 

Elevating the functionality and overall feel of the space, Edison-style string lights run along the perimeter of the pergola, and a heater hangs directly over the top of the outdoor kitchen and dining area. Because the uncovered steel rafters are hollow, there is a natural space to hide the unattractive electrical wires from the outdoor accessories. Delgavio finished setting the scene by arranging comfortable seating zones, and carefully tended garden containers provide pops of color and texture along the edge of the deck.

Ultimate peace of mind in the finished rooftop deck 

Delgavio’s dreamy rooftop project was completed in accordance with the city’s updated fire-resistive construction requirements in the spring of 2022. The deck feels intimate and comfortable, inviting family and friends to enjoy an open-air meal with a view during Chicago’s fair-weather months. When the space is not in use, Delgavio can rest easy knowing that the steel deck frame and custom steel pergola will retain their strength and appearance even after long-term exposure to Chicago’s notoriously harsh winters. “The benefits of using Fortress® products are immeasurable,” Delgavio reported from her rooftop.

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