Cold weather loads snow typically applied to exposed roofs or decks ground snow load commonly 10 psf usually roof live load governs unless snow drifts are considered frost heave condition where soil under footing freezes and exerts upward movement on the foundation bottom of footings must be below frost depth to avoid this.
Residential roof live load.
As a result the live load dead load and distribution of forces are different.
The roof live load used in the design shall be indicated 780 cmr 1607 11.
Where uniform roof live loads are reduced to less than 20 psf 0 96 kn m2 in accordance with section 1607 12 2 1 and are applied to the design of structural members arranged so as to create continulty the reduced roof live load shall be applied to adjacent spans or to alternate spans whichever produces.
Ground snow load might seem somewhat confusing until you read the basic premise that is identified in irc section r301 6 which states.
Applied shall be indicated.
Since it is possible to use the attic for storage the live load of the attic floor is set at 20 psf according to code.
Design loads for residential buildings 3 1 general.
The roof shall be designed for the live load indicated in table r301 6 or the snow load indicated.
0 9d 1 0e effect or 0 9 when resisting the load when permanent.
Minimum design loads for buildings and other structures location uniform load psf kn m2 apartments see residential access floor systems office use.
The live load on a roof is the weight of any temporary objects on the roof.
This issue of live load vs.
Minimum uniformly distributed live loads adapted from sei asce 7 10.
Victor staley a building official in the town of brewster mass responds.
1607 12 1 distribution of roof loads.
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 0w a load factor of 1 6 when adding to load 7.
Where snow isn t a problem the live load can come from people working on the roof and any equipment they take on to the.
1603 1 3 roof snow load.
Unlike the trussed roof live load and dead load of the rafters and ceiling joists must be accounted for as separate systems.
The ground snow load p gf and the flat roof snow load p and if applicable the sloped roof snow load p s shall.
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