Residential Roof Live Load

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.

Residential roof live load. 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. Ground snow load might seem somewhat confusing until you read the basic premise that is identified in irc section r301 6 which states. 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. The roof shall be designed for the live load indicated in table r301 6 or the snow load indicated.

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. The roof live load used in the design shall be indicated 780 cmr 1607 11. 0 9d 1 0e effect or 0 9 when resisting the load when permanent. As a result the live load dead load and distribution of forces are different.

Further in most areas of the united states design winds are produced by either hurricanes or. 1607 12 1 distribution of roof loads. 1603 1 2 roof live load. The ground snow load p gf and the flat roof snow load p and if applicable the sloped roof snow load p s shall.

Also whether live load reduction has been applied. Minimum uniformly distributed live loads adapted from sei asce 7 10. Design loads for residential buildings 3 1 general. Minimum design loads for buildings and other structures location uniform load psf kn m2 apartments see residential access floor systems office use.

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. 0 9d 1 0w a load factor of 1 6 when adding to load 7. Unlike the trussed roof live load and dead load of the rafters and ceiling joists must be accounted for as separate systems. This issue of live load vs.

1603 1 3 roof snow load.