Firehouse

JAN 2017

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Sloping Peaked Roof Construction Reviewing design and construction elements that can impact crews operating interior or atop a peaked roof "I t was like a hangman's t r a p d o o r s u d d e n ly opened." This is how a Yonkers, NY, firefighter described a peaked roof collapse that killed Lt. Harry Korwatch in 1984. Peaked roofs in outer boroughs, suburbs and rural areas are the new roof fire environment. And as fire shifts to the outer parts of the city, firefighters are finding these roofs more dangerous and difficult to work on than on flat roofs—and they certainly pose some unique challenges: • Just to get up on top of a peaked roof, you need two ladders—one to climb to roof level and another to hook onto the ridge and climb up the slope. • A slanted roof surface can make it difficult to maintain balance while performing firefighting functions. • There is no parapet around the edge of a peaked roof, so if you slip, you slide off the roof. • Sloping roofs are designed to shed water and snow, so the load-bearing capacity is reduced. Rookies and veterans who know about flat roofs must learn of the construction and the hazards of peaked roofs. Peaked roof design There are five common sloping peaked roofs found in suburbs and rural areas: • A shed roof has sides sloping up from two bearing walls of different heights. • A gable roof has sides sloping up from two bearing walls. • A hip roof has sides sloping up from four bearing walls. • A gambrel roof has two slopes on each of two sides, with the lower slope steeper than the upper. • A mansard roof has two slopes on each of four sides, with the lower slope steeper than the upper. Each one of these roofs has construc - tion features that firefighters must know in order to operate safely and effectively. For example, a shed roof can have skylights flush with the roof deck, meaning firefighters can crash through them. A gable roof has windows on one or both gable ends that can be used to vent an attic. A hip roof has the lowest roof slope of the four, and this low angle increases the risk of rafter collapse. Collar beams must be used tie roof rafters together, which make them particularly susceptible to collapse. The lower slope of a gambrel roof is far too steep to walk up on, and a stan- dard roof ladder can't be used to assist in climbing this steep slope. And if a mansard roof collapses, it can potentially push out the par- apet supporting the lower slopes around the perimeter. Let's now consider some other sloping peak roof construc- tion features. Attic An attic is like a cockloft except it has storage and sometimes people living in this space. It is essentially a ceilng space intended to insulate the house from the hot and cold roof temperatures. One dif- ference between peaked and flat roofs is how the attic space is configured. An important objective when fighting fire in a dwelling is to keep the fire from extending into the attic space because if flames extend here, it usually means that the entire building will be destroyed and your firefighing efforts have failed. By Vincent Dunn SAFETY & SURVIVAL VINCENT DUNN, a Firehouse ® contributing editor, is a 42-year veteran of the FDNY and a deputy chief (ret.), serving as a division commander for midtown Manhattan. A nationally renowned lecturer, he is the author of the best selling text and DVDs Collapse of Burning Buildings and textbooks Safety and Survival on the Fireground, Command and Control of Fires and Emergencies and his new book Strategy of Firefighting – How to Extinguish Fires. Dunn has a master's degree in urban studies, a bachelor's degree in sociology and an associate's degree in fire administration from Queens College, City University of New York. vincentdunn@earthlink.net Connect with Vin vincent.dunn.10 All peaked roofs have construction features that firefighters must know in order to operate safely and effectively. Photo by Bill Tompkins 20 l Firehouse l January 2017

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