EQ D E S I G N
DESIGNING for EXTREMES Plan now for next winter’s SNOW AND ICE. BY JOHN BLACKBURN
C
oming off the heels of a truly epic storm for the Washington, D.C., area (and most of the East Coast), I thought I’d take a moment to address how design techniques can help barns weather extremes. In the United States, the upper Northeast through to the Midwest are prone to experiencing weather extremes in the form of snow and ice. While we cannot entirely weatherproof a barn, we can make it more resilient to some of the more damaging effects of weather. The roof of a barn needs to be able to withstand the weight of snow or effectively shed it; prevent or reduce the formation of ice dams; redirect roof avalanches from sliding into high traffic or poor drainage areas; and reduce associated noise that could frighten the horses.
Water can build up under shingles Interior heat melts snow
Warm air rises from inside Cold air refreezes water and forms ice dam
SNOW AND ICE
Well-designed natural ventilation can help prevent ice dams that can damage roofs and buildings.
ROO F D E S I G N A N D MAT E RI A L S
In addition to contributing to the Bernoulli principle (which pulls air up and through the barn), that I incorporate for natural ventilation, steeply pitched roofs also contribute to effective, gradual snow shedding and the redistribution of snow load. Ideally the pitch should be between 4/12 and 6/12 to get the optimal shedding effect, although we generally try to keep pitches at 7/12 or more to take full advantage of the chimney effect and Bernoulli principle for natural ventilation.
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Roofing material will also factor into how the snow will be shed. Metal roofs are excellent because they are smooth and slick. They will also stay colder longer, reducing the likelihood that snow will melt and form ice dams (more on this below). Snow will shed from a metal roof even if the pitch is lower. Shingled roofs, however, will slow down the shedding process by holding on to the snow and allowing it to stay in place and accumulate. Consider a steeper pitch if you prefer a shingled roof, as it will facilitate the shedding process over the rougher material.
Architect John Blackburn grew up with horses in eastern Tennessee. His architectural firm, Blackburn Architects, was established in Washington, D.C., in 1983 and has become one of America’s best-known firms specializing in equestrian projects. John’s book, Healthy Stables by Design, has become a standard in the field of horse-stable design. (See page 94)
Now, you might be saying to yourself, “Well, the snow is off the roof, but it’s all over the place. Now what?” Including strategic roof overhangs will complement the steeper pitch by helping to distribute shedding snow away from exterior walls and out of traffic and poor drainage areas. Be wary though—snow sliding off roofs can be noisy and frightening to horses, not to mention dangerous if it falls on you. Snow guards on the roof can help reduce the noise associated with shedding snow and keep huge sheets of it from falling on (and potentially harming) two- and four-legged passersby. Gabled dormers over entryways can also be useful. They help to direct snow off to the sides. Ice dams are another unfortunate side effect of snow-laden roofs. An ice Continued on page 100