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|Howard T. Ennis School
Georgetown, Delaware - All-Span, Inc.
Although Ultra-Span truss systems are most commonly used on new construction, this issue's featured project is an outstanding example of how Ultra-Span can be incorporated in a retrofit application.
The Howard T. Ennis School was like so many other educational facilities built during the 1960s. The two story brick structure was designed with a flat hot tar and gravel roof system. As with most such roofs of this vintage, water leakage and seepage had become a major problem, creating a costly, repetitive maintenance nightmare. In addition, the school district wanted to install new rooftop mechanical units for each classroom that could be hidden from view.
The obvious solution to these retrofit challenges was a sloped roof with a built in mechanical space. Although the traditional approach would have been to utilize a structural “post and purlin” system, architect Becker Morgan wanted to ensure sufficient area for the new air handling units, as well as minimize the number of penetrations in the existing roof membrane.
Ultra-Span partner All-Span, Inc. was brought in to help design an optimal re-roof system to provide an attractive, low maintenance sloped roof while minimizing installation time and classroom disruptions.
As usual, Dave Miller, J.J. Carter, Herb Troyer and the All-Span team were more than up to the challenge! To minimize the number of trusses (and the installation time required), All-Span designed two mono trusses spaced 6 feet on center to cover the 82’ x 305’ main school building. A short “pony wall” was built up along the exterior bearing walls and a row of stub posts spaced 6’ o.c. were installed along the center of the existing roof. With only one center bearing, the number of roof penetrations was reduced from several hundred for a traditional “post and purlin” system to only 50 or so for the Ultra-Span solution.
Adequate installation and maintenance access for the new rooftop units was easily accomplished by designing and building a large mechanical “room” into the trusses covering those areas where the units would be located. With the assistance of the precise layout, connection, and engineered bracing diagrams (an Ultra-Span system exclusive!) provided by All-Span, truss installer K. B. Cold iron was able to retrofit the Ennis School in just two weeks! And, by working evenings and weekends, no class time was lost (great news for the parents and educators, bad news for the kids!)
The Howard T. Ennis re-roof is a perfect example of how our Ultra-Span fabricators can help compress construction cycles and reduce total cost through the speed and efficiency of pre-engineered, factory-built components.