Minimum Roof Pitch For Snow Loads

Flat roof snow loads p f the snow load that is applied to our structure is not the ground snow load but in most cases the flat roof snow load.

Minimum roof pitch for snow loads.

90 mph for both 2003 irc and 2003 ibc. The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems. This can be accomplished by measuring the number of inches the roof rises vertically for every 12 inches it extends horizontally. So you would need to pick the right option as most regular standing seam metal roofs will require a roof pitch of 2 12 or even 3 12 at a minimum.

There are some standing seam metal roofing options available from atas and other manufacturers that can be installed on a roof with pitch of 1 12. The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code. The standing seam metal roof on this ice hockey rink leaked like a sieve a few weeks after the first snow arrived. If the snow weighs 10 pounds per cubic foot and there are 1 5 feet on the roof each square foot of the roof is getting 15 pounds of pressure.

In general determining the pitch of an existing roof is a simple calculation. For example a roof with a 6 inch 12 pitch is one where it rises 6 inches vertically for every 12 inches of the horizontal run. If your roof is 1 000 square feet the total snow load is 15 000 pounds of snow. Importance of a roof pitch.

To figure out the load on your roof take the depth of snow in feet and multiply it by the weight of a cubic foot of snow. A minimum slope of 1 inch per foot is recommended in snow country. The minimum roof pitch is also subject to the standards set forth by the various building codes used in the respective regions. Per 2003 irc and 2003 ibc.

The 1 4 inch per foot slope was not adequate. 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. You could also opt for a pvc flat roofing membrane. In our case let s assume that our structure has a flat roof roof slope 5.