Excerpts from the dailyherald.com:

Prospect Heights Fire Chief Drew Smith recalls that the apartment fire Monday night which displaced about 100 residents in Mount Prospect featured an almost identical layout to a 2018 fire in Prospect Heights. That fire, at the River Trails Condominium complex, destroyed 24 units and damaged 72 others, leaving dozens of residents without homes.

What linked those fires, and several other large apartment blazes in the suburbs since 2018, were the mansard-style roofs, which were popular with builders in the 1960s and ’70s because they allow for additional living space on a building’s top floor. But they present a challenge to firefighters by shielding flames from water as a fire spreads.

“Unfortunately, the reality is that until the fire burns through the roof, the water can’t get on the fire. By that time, it’s just too late,” Smith said.

Similar fires ravaged the Windhaven condominiums in Palatine in 2023, leaving 22 units uninhabitable; the Puente Del Pueblo apartments in West Chicago, also last year, displacing about 100 residents; and the Bristol Court condominium complex in Park Ridge in 2022, injuring five residents and leaving an entire 36-unit building uninhabitable.

Last week’s fire at the Orion Parkview Apartments in Mount Prospect started in the cockloft of the 36-unit building. The intense heat prevented firefighters from battling the blaze offensively from the structure’s interior, forcing them instead to transition to a defensive attack from the outside.

Unlike the common areas beneath it, the attic did not have sprinklers, and the mansard roof prevented water from reaching the flames as they spread.

Named after 17th century French architect Francois Mansart, the mansard roof first was popularized in the design of French homes. It is characterized by its distinctive sloping roofs, which are clad with various types of roofing shingles and pierced by recessed window openings. They fell out of style among U.S. builders after the 1970s, but many buildings with mansard roofs remain in the suburbs.

Smith wrote a report on a 2006 fire at River Trails, the same complex damaged in 2018, for Fire Engineering. It describes how fire and smoke can spread within the roof.

“During overhaul and the investigation, you could look into the mansard from the third floor inside corner apartment and see it run the length of the building without a fire stop”, he wrote.

The best solution is sprinklers, but it’s difficult and costly to install them in attics after construction is complete.

Tags: 17th century French architect Francois Mansart, chicagoareafire.com, fire at the Orion Parkview Apartments, fire at the River Trails Condominium complex, Mansard Roof Design vulnerabilities, Prospect Heights Fire Chief Drew Smith