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.
Water roof live load.
Very slightly over time.
The might of the dead load or lack thereof often defines how much live load it can handle.
Used but they typically defined the load cases or combination stress or strength limits and deflection limits.
Load case a is for a horizontal roof.
Roof assemblies are engineered to withstand serious structural failure due to overloading that is an excessive live load due to the build up of rain water or snow ice as predicted from the geographical climate zone.
These loads are not considered to be per manent because of their inherent degree of variability with respect to time see the definition of loads in ibc 202.
In other words on a steep roof less material would be stacked in a concentrated area at one time to avoid having it slide off.
Roof live loads largest roof loads typically caused by repair and maintenance pitch rise span lr 20 r1r2 12 lr 20 lr horizontal projection roof live load 16 r 1 r 2 live load reduction factors r 1 accounts for size of tributary area of roof column a t r 2 effect of the roof rise.
And from overbearing for example when the pressure differential from excessive winds exceed the resistance of the roof.
Live loads roof live loads snow loads rain loads wind loads and earthquake loads are all examples of variable loads.
Because live loads depend on structural strength knowledge of the exact planned use of the building is critical.
The load cases b to d are for sloping roofs.
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.
Asce guidelines prescribe live loads according to categories of intended occupancy and use per building type.
2attic loads may be included in the floor live load but a 10 psf attic load is typically used only to size ceiling joists adequately for access purposes.
The live load on a roof is the weight of any temporary objects on the roof.
D dead load l live load l r live roof load w wind load s snow load e earthquake load r rainwater load or ice water load.
However if the attic is intended for storage the attic live load or some portion should also be considered for the design of.
