The ibc becomes the governing code for the truss design and associated load paths if the structure falls outside of these limits see irc r301 1 3.
Irc roof live load.
Maximum ground snow load of 70 psf 3352 pa with roof snow load computed as 0 7p g.
Live loads roof live loads snow loads rain loads wind loads and earthquake loads are all examples of variable loads.
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.
2018 irc chapter 3 2020 colorado code consulting llc 2 r301 1 application buildings and structures and all parts thereof shall be constructed to safely support all loads including dead loads live loads roof loads flood loads snow loads wind loads and seismic loads as prescribed by this code.
Live loads for assembly spaces other than those described in this table shall be determined from the occupant load requirements as established by section 1004 of this code using the formula 1 000 net floor area per occupant but shall not be less than 50 psf nor more than 100 psf.
Live loads irc table r301 5 minimum uniformly distributed live loads 2018 irc essentials use live load psf uninhabitable attics without storage 10 uninhabitable attics with limited storage 20 habitable attics and attics served with fixed stairs 30 balconies exterior and decks 40 fire escapes 40 rooms other than sleeping rooms 40 sleeping rooms 30.
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.
To correctly apply the values of the tables and the prescriptive methods of construction build ers must know the structural design criteria in the planning chapter of the code.
Except for uni form live loads at roofs all other minimum uniformly distrib uted live loads lo in table 1607 1 are permitted to be reduced in accordance with section 1607 10 1 or 1607 10 2.
In my region on cape cod we have a ground snow load design of 25 psf which is a greater design load than the live load 12 psf to 20 psf over an entire roof system.
Further in most areas of the united states design winds are produced by either hurricanes or thunderstorms.
1607 10 1 basic uniform live load reduction.
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.
Note the roof is designed for the roof live load not more than 20 psf or the snow load whichever is greater.
2020 colorado code consulting llc 5.
