Archive for December, 2014

Buffalo Roof Collapses

Written by Jerry Vandewater on . Posted in Uncategorized

In reading the news this morning, the paper said that a number of roofs had collapsed under the weight of the snow left by the horrendous storm that dropped a year’s worth of snow in a single day. Other articles spoke to the need for roofers to shovel the snow off of the roofs before more collapses occurred.

While there is no doubt that these collapses occurred, the “techie” in me always wants to know the details. Were these roofs that collapsed residential or commercial? Were they old structures or newer construction? Having spent years analyzing roof structures to determine the viability of installing tile roofs, my mind always wants to know the details. All too often reports like these create perceptions and fears that are based on situational hysteria and generalities. Ebola in America anyone?

There is no doubt that six feet of snow puts a lot of additional stress on a roof (fresh snow weighs approximately 4.5 pounds per cubic foot but can increase to as much as 25 pounds as it “ripens”) but, believe it or not, current building codes are required to anticipate events like this and a properly constructed roof structure should be able to handle even these seemingly outrageous amounts of snow. The problems arise when the structures were not built according to these codes or were built before the code adequately addressed such conditions. The Uniform Building Codes were not around in the early parts of the twentieth century and I suspects that a sizeable percentage of the buildings in the Buffalo area may have predated comprehensive codes and inspection.

Beyond my curiosity about the particulars of the Buffalo failures lies my belief that roofers in this country should be just as knowledgeable about the capabilities of the roof structure as they should be about the best way to cover it up and keep the water out. In an informal survey that I conducted earlier this year on that subject, it was clear that there were a lot of opinions regarding roof strength but a woeful dearth of knowledge regarding the criteria used to determine roof strength.

There seems to be a general understanding that roof strength is in the realm of engineers but few, if any seemed to realize that the engineering and construction criteria has already been figured out and published and it only takes a little research to learn how to determine the capacity of any roof system. It’s amazing to me that so many roofers still rely on the “bounce” test to determine the strength of the roof. Jumping up and down in the center of the roof may give you a quick indication of strength but it is a far cry from performing the type of analysis that I would expect from a contractor that I am considering to do my reroof.

Knowledge of Section 2308/Conventional Lightweight Construction of the International Building Code and familiarity with published span charts should be a standard requirement for anyone qualifying for a roofing license since the longevity of the roofing system very often relies on the integrity if the roof it is attached to. The fact is that it is not that difficult or expensive to reinforce a roof system and this should be something that roofers would be well advised to add to their repertoire.

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