Residential Roof Snow Loads

The roof shall be designed for the live load indicated in table r301 6 or the snow load indicated.

Residential roof snow loads. Overestimation of snow loads can unnecessarily increase the cost of construction. 7 4 1 7 4 4 and asce figure 7 2 below. 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. Minimum uniformly distributed live loads adapted from sei asce 7 10.

The roof or the entire structure can fail if the snow load exceeds the weight the building was designed to shoulder. Victor staley a building official in the town of brewster mass responds. Chapter 16 structural design. If your roof is 1 000 square feet the total snow load is 15 000 pounds of snow.

Axial forces from snow loads and roof live loads should usually not be considered simultaneously with an extreme wind load because they are mutually exclusive on residential sloped roofs. 0 9d 1 0e effect or 0 9 when resisting the load when permanent. 0 9d 1 0w a load factor of 1 6 when adding to load 7. Calculate unbalanced snow load for hip and gable roofs as shown in asce figure 7 5 below.

Minimum design loads for buildings and other structures location uniform load psf kn m2 apartments see residential access floor systems office use. Ground snow load might seem somewhat confusing until you read the basic premise that is identified in irc section r301 6 which states. 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. This issue of live load vs.

Snow loads are influenced by elevation general weather and moisture patterns slope direction exposure roof or trail bridge configuration and wind direction and severity. Residential roof with asphalt wood shingles or shakes would use fig. Where snow isn t a problem the live load can come from people working on the roof and any equipment they. Snow load is the downward force on a building s roof by the weight of accumulated snow and ice.

The live load on a roof is the weight of any temporary objects on the roof. Also extremely relevant to roofs with sections on rain loads snow loads and wind loads. Simple design check representative of worst case combined axial and transverse loading. On the upcodes website.

7 2b with a c s 1 0 p f flat roof snow load in psf. 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. P s sloped roof snow load in psf c s roof slope factor as determined by asce sec.