Roof Pitch Vs Snow Load

If you live in the us our snow load calculator compares the total weight on your roof with the permissible load calculated according to the standards issued by the american society of civil engineers regarding the minimum design loads for buildings and other structures asce7 16.

Roof pitch vs snow load.

That sounds simple enough right. The minimum roof pitch for shedding snow is around 30 or a 6 12 or 7 12 slope although this is not a definite as the material of your roof the direction of the snow and wind are some factors that can affect whether or not snow will slide as roofs of as little as 10 have been reported to shed snow. Even in these arid regions so called flat roofs are still installed with a slight pitch to keep water from pooling on top of the structure. The bottom line is that the irc requires you to design the roof structure to the greater roof load and in my region that s the ground snow load.

In areas where you might get 2 or 3 ft. Of snow you should upgrade to the 50 lb. Typically snow in the western u s. Of snow on the roof a 90 lb.

Is drier and lighter than the moisture laden snow experienced in the eastern part of the country. The sloped roof snow load p s shall be obtained by multiplying the flat roof snow load p f by the roof slope factor c s. One last word on roof pitch is safety. Later that week the race was on as 6 inches of new snow was added to the roof with over a quarter of an inch of freezing rain.

Flat roofs are common with industrial buildings boasting wide roof spans and are also popular in dry climates for houses where there is no need for the roof to help disperse rain and snow. Putting the dangers of falling through out of my mind i continued to shovel the snow easing the creaking roof s snow load. In my region on cape cod we have a ground snow load design of 25 psf which is a greater design load than the live load 12 psf to 20 psf over an entire roof system. The truss could be designed based on the assumption that the 25 psf roof snow load is a factored ground snow load in which case a ground snow load is back calculated using asce 7 based on the specified roof snow load pg 25 psf therein lies the problem with specifying only a roof snow load.

If you get a metal roof in particular and it has a pitch of 5 12 or above that s not going to feel as safe as a lower pitched roof if you re one of those people who like to climb up on your roof and clear branches or do some minor patching around exhaust. The density of the snow makes a significant difference in the weight of the snow. P s c s p f the thermal factor c t from table e 3 determines if a roof is cold or warm slippery surface values shall be used only where the roof s surface is unobstructed and sufficient space is. Roof snow loads indicate the amount of additional force pressing down on a building when snow and ice pile up on the roof during winter storms.