Yesterday we talked about Dead Weight, lateral weight, and Shear Walls. Unfortunately many people neglect to account for Lateral Weight when framing. Obviously that can cause walls and buildings to fail.
- Snow Load - When we are talking about weight, whether it is dead weight or lateral weight the real enemy in all of this is only ONE THING, and that’s snow. The basic weight of a roof or workers walking around on the roof is insignificant.
- The weight of snow up on the roof varies greatly from light fluffy snow weighting roughly 5¼ pounds per square foot all the way up to 12½ pounds per square foot for one foot of snow. Let’s pretend that we are talking about a 48’ Ranch House; that will have about 765 square feet on one half of the roof or an estimated weight of 9,500± pounds of snow. EGAD, that is almost FIVE TONS of snow up on one half of the roof. The other half will have another 5 tons of snow.
- Shear Walls are critical when framing a house? With that enormous amount of weight up on the roof it is critical that everything be built well but only after it is thoroughly calculated.
- The Dead Weight is carried by the vertical walls. The Dead Weight doesn’t cause a problem unless things are out of plumb and square; when that happens there is going to be some Lateral Weight that needs to be accounted for. Shear Walls work to eliminate the effect of Lateral Weight.
- The huge amount of weight on the roof is an essential part of framing. Knowing where the Studs and Shear Walls are assembled is very important.
Also, it only makes common sense that these snow loads vary greatly from one area to another. As we all know here in Vermont the amount of snow fall is much greater up in The Higher Elevations. Often the forecast will be for light showers here in The Champlain Valley and up in The Higher Elevations several inches of snow can fall. Your new home needs to be built to accommodate the snow load at your location. Obviously down south much of this is not a significant factor. But then………, they don’t live in Vermont.
Have a good weekend!