On a roof with a slope greater than 4 to 12 the live load limit is typically adjusted downward from 20 psf to 15 psf to allow for the relatively greater dead load on the steeper roof.
Live load roof deck chapter 16.
For roofs this exception only applies when the metal sheets have no roof covering.
The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures.
1603 1 3 roof snow load data.
Where uniform roof live loads are reduced to less than 20 psf 0 96 kn m 2 in accordance with section 1607 12 2 1 and are applied to the design of structural members arranged so as to create continuity the reduced roof live load shall be applied to adjacent spans or to alternate spans whichever produces the most unfavorable load effect.
1603 1 3 roof snow load.
Ibc 2012 defines live load l as roof live load greater than 20 psf and floor live load.
For secondary wall members supporting formed metal siding the design wind load deflection shall not exceed l 90.
Earthquake and wind load effects are an exception to this.
In areas where the ground snow load pg exceeds 10 pounds per square foot psf 0 479 kn m2 the following additional information shall also be provided regardless of whether snow loads govern the design of the roof.
So with the roof dance floor example per ibc the live load would not be roof live load but live load assuming the live load magnitude exceeded 20 psf.
Roof live load l r is defined as roof live load of 20 psf or less.
Factored loads are determined by multiplying nominal loads that is loads specified in chapter 16 of the ibc by a load factor which is typically greater than or less than 1 0.
Live load reduction of the uniformly distributed floor live loads if used in the design shall be indicated.
Ibc provides a different definition for live load and roof live load in chapter 16 compared to that given in asce 7 chapter 4.
In areas where the ground snow load pg exceeds 10 pounds per square foot psf 0 479 kn m2 the following additional information shall also be provided regardless of whether snow loads govern the design of the roof.
The ground snow load pg shall be indicated.
A smaller area is liable to have a higher live load than the regular residential floor live 40 psf.
The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process.
1603 1 2 roof live load.
A load factor of 1 0 is used to determine the maximum effects.
The ground snow load pg shall be indicated.
The roof live load used in the design shall be indicated for roof areas 1607 11.
Roof snow load data.
The ground snow load p g shall be indicated.
The roof and snow live loads used in the design shall be indicated for roof areas sections 1607 12 and 1608.